document_title: Flush toilet

question_text: where does the water from the toilet come from

question_tokens: where does the water from the toilet come from

text: Flush toilet

text: Operation[edit]

text: The focus of this article is a flush toilet that uses a mechanical flush from a water cistern that is above the toilet.

text: Mechanical flush from a cistern[edit]

text: A typical flush toilet is a vitreous, ceramic bowl containing water, plus plumbing to rapidly fill it with more water. The water in the toilet bowl is connected to a hollow drain pipe shaped like an upside-down U connecting the drain. One side of the U channel is arranged as a hollow siphon tube longer than the water in the bowl is high. The siphon tube connects to the drain. The top of the upside-down U-shaped drain pipe limits the height of the water in the bowl before it flows down the drain. If water is poured slowly into the bowl it simply flows over the rim of the upside-down U and pours slowly down the drain—thus the toilet does not flush. The standing water in the bowl acts as a barrier to sewer gas coming out of the sewer through the drain, and also as a receptacle for waste. Sewer gas is vented through a separate vent pipe attached to the sewer line.

text: When a user flushes a toilet, a "toilet flapper valve" (not to be confused with a type of check valve) opens and allows water from a reservoir tank to quickly enter the toilet bowl. This rapid influx from the tank causes the swirling water in the bowl to rapidly rise and fill the U-shaped inverted siphon tube mounted in the back of the toilet. This full siphon tube starts the toilet's siphonic action. The siphon action quickly (4–7 seconds) “pulls” nearly all of the water and waste in the bowl and the on-rushing tank water down the drain—it flushes. When most of the water has drained out of the bowl, the continuous column of water up and over the bottom of the upside-down U-shaped drain pipe (the siphon) is broken when air enters the siphon tube. The toilet then gives its characteristic gurgle as the siphonic action ceases and no more water flows out of the toilet. After flushing, the flapper valve in the water tank closes; water lines and valves connected to the water supply refill the toilet tank and bowl. Then the toilet is again ready for use.

text: At the top of the toilet bowl is a rim with many angled drain holes that are fed from the tank, which fill, rinse, and induce swirling in the bowl when it is flushed. Mounted above the toilet is a large holding tank with approximately 1.2 to 1.6 U.S. gallons (4.5 to 6.1 L) of water in modern designs. This tank is built with a large drain 2.0 to 3.0 inches (5.08 to 7.62 cm) diameter hole at its bottom covered by a flapper valve that allows the water to rapidly leave the holding tank. The plumbing is built to allow entry of the tank’s water into the toilet in a very short period. This water pours through the holes in the rim and a siphon jet hole about 1.0 inch (2.54 cm) diameter in the bottom of the toilet. Some designs use a large hole in the front of the rim to allow faster filling of the bowl.

text: Manual flush (pour flush)[edit]

text: Another variant of the flush toilet is the pour-flush toilet.[5] This type of flush toilet has no cistern, but is flushed manually with a few litres of a small bucket. The flushing can use as little as 2–3 litres.[5] This type of toilet is common in many Asian countries. The toilet can be connected to one or two pits, in which case it is called a "pour flush pit latrine" or a "twin pit pour flush pit latrine". It can also be connected to a septic tank.

text: Manufacture[edit]

text: A toilet's body is typically made from vitreous china, which starts out as an aqueous suspension of various minerals called a slip. It takes about 20 kilograms (44 lb) of slip to make a toilet.[citation needed]

text: This slip is poured into the space between plaster of Paris molds. The toilet bowl, rim, tank and tank lid require separate molds. The molds are assembled and set up for filling and the slip-filled molds sit for about an hour after filling. This allows the plaster molds to absorb moisture from the slip, which makes it semisolid next to the mold surfaces but lets it remain liquid further from the surface of the molds. Then, the workers remove plugs to allow any excess liquid slip to drain from the cavities of the mold (this excess slip is recycled for later use). The drained-out slip leaves hollow voids inside the fixture, using less material to keep it both lighter and easier to fire in a kiln. This molding process allows the formation of intricate internal waste lines in the fixture; the drain's hollow cavities are poured out as slip.

text: At this point, the toilet parts without their molds look like and are about as strong as soft clay. After about one hour the top core mold (interior of toilet) is removed. The rim mold bottom (which includes a place to mount the holding tank) is removed, and it then has appropriate slanted holes for the rinsing jets cut, and the mounting holes for tank and seat are punched into the rim piece. Valve holes for rapid water entry into the toilet are cut into the rim pieces. The exposed top of the bowl piece is then covered with a thick slip and the still-uncured rim is attached on top of the bowl so that the bowl and hollow rim are now a single piece. The bowl plus rim is then inverted, and the toilet bowl is set upside down on the top rim mold to hold the pieces together as they dry. Later, all the rest of the mold pieces are removed. As the clay body dries further it hardens more and continues to shrink. After a few hours, the casting is self-supporting, and is called greenware.

text: After the molds are removed, workers use hand tools and sponges to smooth the edges and surface of the greenware, and to remove the mold joints or roughness: this process is called "fettling". For large scale production pieces, these steps may be automated. The parts are then left outside or put in a warm room to dry, before going through a dryer at about 93 °C (199 °F), for about 20–36 hours.[6]

text: After the surfaces are smoothed, the bowls and tanks are sprayed with glaze of various kinds to get different colors. This glaze is designed to shrink and contract at the same rate as the greenware while undergoing firing. After being sprayed with glaze, the toilet bowls, tanks, and lids are placed in stacks on a conveyor belt or "car" that slowly goes through a large kiln to be fired. The belt slowly moves the glaze-covered greenware into a tunnel kiln, which has different temperature zones inside it starting at about 200 °C (392 °F) at the front, increasing towards the middle to over 1,200 °C (2,190 °F) degrees and exiting around out 90 °C (194 °F). During the firing in the kiln, the greenware and glaze are vitrified as one solid finished unit. Transiting the kiln takes glaze-covered greenware around 23–40 hours.

text: After the pieces are removed from the kiln and fully cooled, they are inspected for cracks or other defects. Then, the flushing mechanism may be installed on a one-piece toilet. On a two-piece toilet with a separate tank, the flushing mechanism may only be placed into the tank, with final assembly at installation.

text: A two-piece attaching seat and toilet bowl lid are typically mounted over the bowl to allow covering the toilet when it is not in use and to provide seating comfort. The seat may be installed at the factory, or the parts may be sold separately and assembled by a plumbing distributor or the installer.[6]

text: Water usage[edit]

text: The amount of water used by conventional flush toilets usually make up a significant portion of personal daily water usage: for example, it could be as much as 50 liters (13 U.S. gal) per person per day if a person flushes his or her toilet five times per day with 10 liters per flush.

text: Modern low-flush toilet designs allow the use of much less water per flush —4.5 to 6 liters (1.2 to 1.6 U.S. gal) per flush.[citation needed]

text: Some users do not flush their toilets after urination, in order to save water.[7]

text: Dual flush toilets allow the user to select between a flush for urine or feces, saving a significant amount of water over conventional units. The flush handle on some of these toilets is pushed up for one kind of flush and down for the other.[8] In other designs, a segmented flush pushbutton is used; pressing the smaller section releases less water.

text: Flush toilets may, if plumbed for it, use greywater (water previously used for washing dishes, laundry and bathing) for flushing rather than potable water (drinking water). Heads (on ships) are typically flushed with seawater.

text: Flushing mechanism[edit]

text: The flushing mechanism provides a large flow of water into the bowl (which is described later in this article). The mechanism usually incorporates one or more parts of the following designs:

text: Tank fill valve[edit]

text: Tank fill valves are found in all tank-style toilets. The valves are of two main designs: the side-float design and the concentric-float design. The side-float design has existed for over a hundred years. The concentric design has only existed since 1957, but is gradually becoming more popular than the side-float design.

text: The side-float design uses a float on the end of a lever to control the fill valve. The float is usually shaped like a ball, so the mechanism is called a ball-valve or a ballcock. Cock is a term for valve; see, for example, stopcock. The float was originally made from copper sheet, but it is now usually plastic. The float is located to one side of the main valve tower at the end of a rod or arm. As the side-float rises, so does the side-float-arm. The arm connects to the fill valve that blocks the water flow into the toilet tank, and thus maintains a constant level in the tank.

text: The newer concentric-float fill valve consists of a tower which is encircled by a plastic float assembly. Operation is otherwise the same as a side-float fill valve, even though the float position is somewhat different. By virtue of its more compact layout, interference between the float and other obstacles (tank insulation, flush valve, and so on) is greatly reduced, thus increasing reliability. The concentric-float fill valve is also designed to signal to users automatically when there is a leak in the tank, by making much more noise when a leak is present than the older style side-float fill valve, which tends to be nearly silent when a slow leak is present.

text: Tank style with flapper-flush valve[edit]

text: In a tank-based system, the storage tank (or cistern) collects between 6 and 17 litres (1.3 and 3.7 imp gal; 1.6 and 4.5 US gal) of water over a period of time. This system is suitable for locations plumbed with 1⁄2 inch (13 mm) or 3⁄8 inch (9.5 mm) water pipes. These small diameter pipes cannot supply water quickly enough to flush the toilet; the tank is needed to supply a large volume of water in a short time. The storage tank is kept full by a tank fill-valve. The storage tank is usually mounted directly upon the bowl, although some tanks are mounted on the wall a few feet above the bowl in an attempt to increase the flush water pressure as it enters the bowl. Tanks near the ceiling are flushed by means of a dangling pull chain, often with a large ornate handle, connected to a flush lever on the cistern itself. "Pulling the chain" remains a British euphemism for flushing the toilet, although this type of tank or cistern is becoming rare. A similar German expression is Wasser ziehen ("to pull water").

text: In tanks using a flapper-flush valve, the outlet at the bottom of the tank is covered by a buoyant (plastic or rubber) cover, or flapper, which is held in place against a fitting (the flush valve seat) by water pressure. To flush the toilet, the user pushes a lever, which lifts the flush valve from the valve seat. The valve then floats clear of the seat, allowing the tank to empty quickly into the bowl. As the water level drops, the floating flush valve descends back to the bottom of the tank and covers the outlet pipe again. This system is common in homes in the US and in continental Europe. Recently this flush system has also become available in the UK due to a change in regulations.

text: Tank style with siphon-flush valve[edit]

text: This system, invented by Albert Giblin and common in the UK, uses a storage tank similar to that used in the flapper-flush-valve system above.[9] This flush valve system is sometimes referred to as a valveless system, since no traditional type of valve is required. Some would argue, however, that any system of regulating the flow of a fluid is still technically a valve. In the siphon-flush-valve system, the user pushes a lever or button, forcing the water up into the tank siphon passageway which then empties the water in the tank into the bowl. The advantage of a siphon over the flush valve is that it has no sealing washers that can wear out and cause leaks, so it is favoured in places where there is a need to conserve water.

text: Until recently, the use of siphon-type cisterns was mandatory in the UK to avoid the potential waste of water by millions of leaking toilets with flapper valves but due to EU harmonisation the regulations have changed. These valves can sometimes be more difficult to operate than a "flapper"-based flush valve because the lever requires more torque than a flapper-flush-valve system. This additional torque required at the tank lever is due to the fact that a user must forcefully lift a certain amount of water up into the siphon passageway in order to initiate the siphon action in the tank.

text: Older installations, known as "high suite combinations", used a high-level cistern (tank), fitted above head height, that was operated by pulling a chain hanging down from a lever attached to the cistern. When more modern close-coupled cistern and bowl combinations were first introduced, these were first referred to as "low suite combinations". Modern versions have a neater-looking low-level cistern with a lever that the user can reach directly, or a close-coupled cistern that is even lower down and integrated with the bowl. In recent decades the close coupled tank/bowl combination has become the most popular residential system, as it has been found by ceramic engineers that improved waterway design is a more effective way to enhance the bowl's flushing action than high tank mounting.

text: Dual flush toilets[edit]

text: Dual flush versions of this design are now widely available. They have one level of water for liquid waste and a higher level for solid waste. In countries such as Australia, Israel, Singapore or Germany which either have limitations on water consumption or where people are keen to save water, dual flush toilets are now common in both homes and public washrooms.

text: Tank style with high-pressure or pressure-assist valve[edit]

text: This system uses water main pressure to pre-pressurize a plastic tank located inside what otherwise appears to be the more typical ceramic flush tank. A flush cycle begins each time a user flushes the bowl. After a user flushes and the water in the pre-pressurized tank has finished emptying into the bowl, the outlet valve in the plastic tank shuts. Then the high pressure water from the main refills the plastic tank. Inside the tank is an air-filled balloon-like rubber diaphragm. As the higher-pressure mains water enters the tank, the rubber diaphragm is also pressurized and shrinks accordingly.

text: During flushing, the compressed air inside the diaphragm pushes the water into the bowl at a flow rate which is significantly higher than a tank style gravity-flow toilet. This system requires less water than a gravity-flow toilet- or alternatively can be more effective for a similar amount of water. Pressure-assist toilets are sometimes found in both private (single, multiple, and lodging) bathrooms as well as light commercial installations (such as offices). They seldom clog, but the pressurized tanks require replacement about once every 10 years. They also tend to be noisier - a possible concern for residential settings. Pressure-assist toilets from several companies use 1.4 US gallons (5.3 l) to 1.0 US gallon (3.8 l) per flush.

text: New toilets that use similar pressure-assist technology along with a bowl and trapway designed to enhance the siphon effect use only 0.8 US gallons (3.0 l) per flush, or 0.5 US gallons (1.9 l) / 0.95 US gallons (3.6 l) for dual flush models.[10] This design is also much quieter than other pressure-assist or flushometer toilets.

text: Tankless style with high-pressure (flushometer) valve[edit]

text: In 1906, William Sloan first made his "flushometer" style toilet flush valve, incorporating his patented design,[11] available to the public. The design proved to be very popular and efficient, and remains so to this day. Flushometer toilet flush valves are still often installed in commercial restrooms, and are frequently used for both toilets and urinals. Since they have no tank, they have zero recharge time, and can be used immediately by the next user of the toilet. They can be easily identified by their distinctive chrome pipe-work, and by the absence of a toilet tank or cistern, wherever they are employed.

text: Some flushometer models require the user to either depress a lever or press a button, which in turn opens a flush valve allowing mains-pressure water to flow directly into the toilet bowl or urinal. Other flushometer models are electronically triggered, using an infrared sensor to initiate the flushing process. Typically, on electronically triggered models, an override button is provided in case the user wishes to manually trigger flushing earlier. Some electronically triggered models also incorporate a true mechanical manual override which can be used in the event of the failure of the electronic system. In retrofit installations, a self-contained battery-powered or hard-wired unit can be added to an existing manual flushometer to flush automatically when a user departs.

text: Once a flushometer valve has been flushed, and after a preset interval, the flushometer mechanism closes the valve and stops the flow. The flushometer system requires no storage tank, but requires a high volume of water in a very short time. Thus a 3⁄4 inch (22 mm) pipe at minimum, or preferably a 1-inch (29 mm) pipe, must be used, but as the high volume is used only for a short duration, very little water is used for the amount of flushing efficacy delivered. Water main pressures must be above 30 pounds per square inch (2.1 bar). While the higher water pressure employed by a flushometer valve does scour the bowl more efficiently than a gravity-driven system, and while fewer blockages typically occur as a result of this higher water pressure, flushometer systems still require approximately the same amount of water as a gravity system to operate (1.6 gpf).

text: Flushing with non-potable water sources[edit]

text: Raw water flushing, including seawater flushing, is a method of water conservation, where raw water, such as seawater, is used for flush toilets. Such systems are used in places such as the majority of cities and towns in Hong Kong (see water supply and sanitation in Hong Kong),[12] Gibraltar, and Avalon, California, United States.[citation needed]

text: Bowl design[edit]

text: This section does not cite any sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (October 2015) (Learn how and when to remove this template message)

text: The "bowl", "loo", or "pan" of a toilet is the receptacle that receives bodily waste. A toilet bowl is most often made of a ceramic, but can sometimes be made of stainless steel or composite plastics. Toilet bowls are mounted in any one of three basic manners: above-floor mounted (pedestal), wall mounted (cantilever), or in-floor mounted (squat toilet).

text: Within the bowl, there are three main waterway design systems: the siphoning trapped system (found primarily in North American residential installations, and in North American light commercial installations), the non-siphoning trapped system (found in most other installations both inside and outside of North America), and the valve-closet system (found in many specialty applications, such as in trains, planes, buses, and other such installations around the world). Older style toilets called "washout" toilets are now only found in a few locations.

text: Siphoning toilet[edit]

text: The siphoning toilet is perhaps the most popular design in North America for residential and light commercial toilet installations. Some other terms for these types of toilets are "siphon jet", "siphon wash", and in North America, "wash down". All siphoning toilets incorporate an "S" shaped waterway. The waterways in these toilets are designed with slightly smaller diameters than a non-siphoning toilet, so that the waterway will naturally fill up with water, each time it is flushed, thus creating the siphon action. To flush the toilet the user activates a flushing mechanism (see above), which pours a large quantity of water quickly into the bowl. This creates a flow large enough to purge the bowl's waterway of all air, thus causing the bowl to empty rapidly due to the siphon action that has been created. This flow stops as soon as the water level in the bowl drops below the first bend of the siphon, allowing air to enter the S-pipe to break the column of liquid and to halt the siphonic action.

text: A "true siphoning toilet" can be easily identified by the noise it makes. If it can be heard to suck air down the drain at the end of a flush, then it is a true siphoning toilet. If not, then it is either a double trap siphonic or a non-siphoning toilet.

text: Double trap siphonic toilet[edit]

text: The double trap siphonic toilet is a less common type that is exceptionally quiet when flushed. There is a device known as an aspirator which uses the flow of water on a flush to suck air from the cavity between the two traps, reducing the air pressure there to create the siphon which sucks water and waste from the toilet bowl. Towards the end of the flush the aspirator ceases being covered in water, thus allowing air into the cavity between traps to break the siphon without the noise while the final flush water fills the pan.[13][14]

text: Valve closet[edit]

text: The valve closet has a valve or flap at the exit of the bowl with a watertight seal to retain a pool of water in the pan. When the toilet is flushed, the valve is opened and the water in the pan flows rapidly out of the bowl into the drains, carrying the waste with it.

text: The earliest type of toilet, the valve closet is now rarely used for water-flush toilet systems. More complicated in design than other toilets, this design has lower reliability and is more difficult to maintain or repair. The most common use for valve closets is now in portable closets for caravans, camping, trains, and aircraft, where the flushing fluid is recycled. This design is also used in train carriages for use in areas where the waste is allowed to be simply dumped between the tracks (the flushing of such toilets is generally prohibited when the train is in a station).

text: Washout toilet[edit]

text: Washout toilets have a flat platform with a shallow pool of water. They are flushed by a jet of water from the back that drives excreta into the trap below. From there, the water flow removes it into the sewage system. An advantage of the design is that users will not get splashed from below. Washout toilets have a shallow pool of water into which waste is deposited, with a trapped drain just behind this pool. Waste is cleared out from this pool of water by being swept over into the trap (usually either a P-trap or an S-trap) and then beyond into a sewer by water from the flush. Washout pans were amongst the first types of ceramic toilets invented and since the early 1970s are now only found in a decreasing number of localities in continental Europe.[citation needed] A washout toilet is a kind of flush toilet which was once predominantly used in Germany, Austria and France. It was patented in Britain by George Jennings in 1852 and remained the standard toilet type in Britain throughout the 19th century.[15]

text: Shelf style (Flachspüler)[edit]

text: In the shelf style or Flachspüler ("shallow flush") toilet, the bowl is designed with a receiver shelf to hold the fecal matter out of the water prior to flushing (i.e. the feces do not fall directly into standing water). The design prevents the occurrence of any splash-up which commonly happens when fecal matter plunges into the standing water of other toilet designs (although substantial deposits may cause splash-up problems of their own). Examples of this type of toilet can be found in Australia, Austria, the Czech Republic, Germany, Hungary, the Netherlands, and some regions of Poland, although it is becoming less common.

text: One disadvantage of this design is that it may require the more intense use of a toilet brush to remove bits of feces that may have left marks on the shelf[citation needed]. Additionally, this design presents the disadvantage of creating a strong lingering odor since the feces are not submerged in water immediately after excretion. Similar designs are found in some early toilets in the US, one particular brand being labeled the "Grand Niagara", as the flushing of the shelf created a waterfall effect into the drain chamber.[citation needed]

text: Simple flush toilets in old railcars[edit]

text: This type of toilet is used on most older style Russian trains, made in Eastern Germany (Ammendorf factory, design dated probably to the 1950s), employing a pan-like shutter valve discharging waste directly onto the trackbed below. Usage of this toilet is permitted only while the train is moving, and outside of major cities. These designs are being phased out, together with the old trains, and are being replaced with modern vacuum systems.

text: The British singer Ian Wallace composed and performed the humorous song "Never Do It at the Station", which mentioned the old-fashioned trackbed dumping toilets which were still in use during the mid-20th century in Britain. The song first advised frugal travelers to save money by avoiding pay toilets in train stations, but also reminded polite passengers not to use the onboard "loo" while the train was stopped at a station.[16]

text: Squat toilets[edit]

text: In many parts of Asia, people traditionally use the toilet in a squatting position. This applies to defecation and urination by males and females. Therefore, homes and public washrooms have squat toilets, with the toilet bowl installed in the floor. This has the advantages of not needing an additional toilet seat and also being more convenient for cultures where people use water to wash their genitals instead of toilet paper. However, Western-style toilets that are mounted at sitting height and have a plastic seat have become popular as well. Many public washrooms have both squatting and sitting toilets.

text: In western countries, instructions have been put up in some public toilets on the correct use of a sitting-style toilet. This is to avoid breaking the toilet or seat if someone attempts to squat on the edges.[17][18][19][20]

text: In India, the "Anglo-Indian" design allows the same toilet to be used in the sitting or the squatting position.

text: Low-flow and high-efficiency flush toilets[edit]

text: Since 1994, there is a significant move towards using less water for flushing flush toilets. This has resulted in the emergence of low flush toilet designs and local or national standards on water consumption for flushing. In addition, some people modify their existing high flush toilet to use less water by placing a brick or water bottle into the toilet's water tank.[21] Other modifications are often done on the water system itself (such as by using greywater), or a system that pollutes the water less; hence more efficient use of the water is accomplished.

text: Urine diversion flush toilets, which were developed in Sweden, save water by using less water, or even no water, for the urine flush compared to about six litres for the feces flush.

text: US standards for new toilets[edit]

text: Pre-1994 residential and pre-1997 commercial flush toilets in the United States typically used 3.4 US gallons (13 L) of water per flush (gpf or lpf). In 1992, the United States Congress passed the Energy Policy Act of 1992, which mandated that beginning in 1994 common flush toilets use only 1.6 US gallons (6.1 L).[22] In response to the Act, manufacturers produced low-flow toilets, which many consumers did not like because they often required more than one flush to remove solids. People unhappy with the reduced performance of the low-flow toilets resorted to driving across the border to Canada or Mexico, or buying salvaged toilets from older buildings.[23] Manufacturers responded to consumers' complaints by improving the toilets. The improved products are generally identified as high efficiency toilets or HETs. HETs possess an effective flush volume of 1.3 US gallons (4.9 L) or less.[24] HETs may be single-flush or dual-flush. A dual-flush toilet permits its user to choose between two amounts of water, depending on whether they generated solid or liquid waste.[25] Some HETs are pressure-assisted (or power-assisted or pump-assisted or vacuum-assisted).

text: The performance of a flush-toilet may be rated by a Maximum Performance (MaP) score. The low end of MaP scores is 250 (250 grams of simulated fecal matter). The high end of MaP scores is 1000. A toilet with a MaP score of 1000 should provide trouble-free service. It should remove all waste with a single flush; it should not plug; it should not harbor any odor; it should be easy to keep clean. The United States Environmental Protection Agency uses a MaP score of 350 as the minimum performance threshold for HETs.[24] 1.6 gpf toilets are also sometimes referred as ULF (Ultra Low Flow) toilets.

text: Methods used to make up for the inadequacies of low flow toilets include using thinner toilet paper,[26] plungers, and adding extra cups of water to the bowl manually.[27]

text: Maintenance and hygiene[edit]

text: Clogging[edit]

text: If clogging occurs, it is usually the result of an attempt to flush unsuitable items, or too much toilet paper.[28] Flushing of large amounts of hair should also be avoided. However, clogging can occur spontaneously due to limescale fouling of the drain pipe, or by overloading the stool capacity of the toilet. Stool capacity varies among toilet designs and is based on the size of the drainage pipe, the capacity of the water tank, the velocity of a flush, and the method by which the water attempts to vacate the bowl of its contents. The size and consistency of the stool is also a contributing, but hard-to-predict factor.

text: In some countries, clogging has become more frequent due to regulations that require the use of small-tanked low-flush toilets in attempt to conserve water.[citation needed] Sometimes, three to four flushes periodically during the use of a low-flush toilet may be required to prevent clogging, thus using more water than larger-tanked toilets. Designs which increase the velocity of flushed water or improve the travel path can improve low-flow reliability.

text: Partial clogging is particularly insidious, as it is usually not discovered immediately, but only later by an unsuspecting user trying to flush a loaded toilet. Overflowing of the water mixed with excrement may then occur, depending on the bowl volume, tank capacity and severity of clogging. For this reason, rooms with flush toilets may be designed as wet rooms, with a second drain on the floor, and a shower head capable of reaching the whole floor area. Common means to remedy clogging include use of a toilet plunger, drain cleaner or a plumber's snake.

text: Aerosols[edit]

text: Studies have shown aerosol droplets are produced by flushing the toilet, that enter the air of the room.[29] No proven cases of infection have been found, and the risk is unknown.[30][31] A Fecal-oral route was demonstrated for aerosol droplets that are produced by flushing the toilet. These aerosols are also called "toilet plume".

text: History[edit]

text: Ancient flush toilet systems[edit]

text: Toilets that used water were used in the Indus Valley Civilization. The cities of Harappa and Mohenjo-daro had a flush toilet in almost every house, attached to a sophisticated sewage system.[32] See also Sanitation of the Indus Valley Civilisation. They also appear in Knossos and Akrotiri of the ancient Minoan civilization from the 2nd millennium BC.[33][34]

text: Primitive forms of flush toilets have been found to exist since ancient Neolithic times. The oldest neolithic village in Britain, dating from circa 31st century BC, Skara Brae, Orkney, used a form of hydraulic technology for sanitation.[35] The village's design used a river and connecting drainage system to wash waste away.

text: Similar toilets were in use throughout the Roman Empire from the 1st through 5th centuries AD. A very well-preserved example are the latrines at Housesteads on Hadrian's Wall in Britain. Such toilets did not flush in the modern sense, but had a continuous stream of running water to wash away waste. With the fall of the Roman Empire, these toilet systems fell into disuse.

text: Development of the flush toilet[edit]

text: In 1596, Sir John Harington (1561–1612) published A New Discourse of a Stale Subject, Called the Metamorphosis of Ajax, describing a forerunner to the modern flush toilet installed at his house at Kelston in Somerset.[36] The design had a flush valve to let water out of the tank, and a wash-down design to empty the bowl. He installed one for his godmother Queen Elizabeth I at Richmond Palace.

text: With the onset of the Industrial Revolution and related advances in technology, the flush toilet began to emerge into its modern form. A crucial advance in plumbing was the S-trap, invented by the Scottish mechanic Alexander Cumming in 1775, and still in use today.[37] This device uses the standing water to seal the outlet of the bowl, preventing the escape of foul air from the sewer.[37] His design had a sliding valve in the bowl outlet above the trap. Two years later, Samuel Prosser applied for a British patent for a "plunger closet".

text: Prolific inventor Joseph Bramah began his professional career installing water closets (toilets) that were based on Alexander Cumming's patented design of 1775. He found that the current model being installed in London houses had a tendency to freeze in cold weather. In collaboration with a Mr Allen, he improved the design by replacing the usual slide valve with a hinged flap that sealed the bottom of the bowl.

text: He also developed a float valve system for the flush tank. Obtaining the patent for it in 1778, he began making toilets at a workshop in Denmark Street, St Giles.[38] The design was arguably the first practical flush toilet, and production continued well into the 19th century, used mainly on boats.

text: Industrial production[edit]

text: It was only in the mid-19th century, with growing levels of urbanisation and industrial prosperity, that the flush toilet became a widely used and marketed invention. This period coincided with the dramatic growth in the sewage system, especially in London, which made the flush toilet particularly attractive for health and sanitation reasons.

text: George Jennings established a business manufacturing water closets, salt-glaze drainage, sanitary pipes and sanitaryware at Parkstone Pottery in the 1840s, where he popularized the flush toilet to middle class. At The Great Exhibition at Hyde Park held from 1 May to 15 October 1851, George Jennings installed his Monkey Closets in the Retiring Rooms of The Crystal Palace. These were the first public pay toilets (free ones did not appear until later), and they caused great excitement. During the exhibition, 827,280 visitors paid one penny to use them; for the penny they got a clean seat, a towel, a comb, and a shoe shine. "To spend a penny" became a euphemism (now archaic) for going to the toilet.[39]

text: When the exhibition finished and moved to Sydenham, the toilets were to be closed down. However, Jennings persuaded the organisers to keep them open, and the toilet went on to earn over £1000 a year. He opened the first underground convenience at the Royal Exchange in 1854. He received a patent in 1852 for an improved construction of water-closet, in which the pan and trap were constructed in the same piece, and so formed that there was always a small quantity of water retained in the pan itself, in addition to that in the trap which forms the water-joint. He also improved the construction of valves, drain traps, forcing pumps and pump-barrels. By the end of the 1850s building codes suggested that most new middle-class homes in British cities were equipped with a water closet.

text: Another pioneering manufacturer was Thomas William Twyford, who invented the single piece, ceramic flush toilet.[40] The 1870s proved to be a defining period for the sanitary industry and the water closet; the debate between the simple water closet trap basin made entirely of earthenware and the very elaborate, complicated and expensive mechanical water closet would fall under public scrutiny and expert opinion.[40] In 1875, the "wash-out" trap water closet was first sold and was found as the public's preference for basin type water closets. By 1879, Twyford had devised his own type of the "wash out" trap water closet, he titled it the "National", and became the most popular wash-out water closet.[40]

text: By the 1880s, the free-standing water closet was sold and quickly gained popularity; the free-standing water closet was able to be cleaned more easily and was therefore a more hygienic water closet. Twyford's "Unitas" model was free standing and made completely of earthenware. Throughout the 1880s he submitted further patents for improvements to the flushing rim and the outlet. Finally in 1888, he applied for a patent protection for his "after flush" chamber; the device allowed for the basin to be refilled by a lower quantity of clean water in reserve after the water closet was flushed.[41] The modern pedestal "flush-down" toilet was demonstrated by Frederick Humpherson of the Beaufort Works, Chelsea, England in 1885.[42]

text: The leading companies of the period issued catalogues, established showrooms in department stores and marketed their products around the world. Twyford had showrooms for water closets in Berlin, Germany; Sydney, Australia; and Cape Town, South Africa. The Public Health Act 1875 set down stringent guidelines relating to sewers, drains, water supply and toilets and lent tacit government endorsement to the prominent water closet manufacturers of the day.

text: Contrary to popular legend, Sir Thomas Crapper did not invent the flush toilet. He was, however, in the forefront of the industry in the late 19th century, and held nine patents, three of them for water closet improvements such as the floating ballcock. His flush toilets were designed by inventor Albert Giblin, who received a British patent for the "Silent Valveless Water Waste Preventer", a siphon discharge system.[43] Crapper popularized the siphon system for emptying the tank, replacing the earlier floating valve system which was prone to leaks.[44][45][46]

text: Spread and further developments[edit]

text: Although flush toilets first appeared in Britain, they soon spread to the Continent. The first such examples may have been the three "waterclosets" installed in the new town house of banker Nicolay August Andresen on 6 Kirkegaten in Christiania, insured in January 1859. The toilets were probably imported from Britain, as they were referred to by the English term "waterclosets" in the insurance ledger. Another early watercloset on the European continent, dating from 1860, was imported from Britain to be installed in the rooms of Queen Victoria in Ehrenburg Palace (Coburg, Germany); she was the only one who was allowed to use it.

text: In America, the chain-pull indoor toilet was introduced in the homes of the wealthy and in hotels, soon after its invention in England in the 1880s. Flush toilets were introduced in the 1890s. William Elvis Sloan invented the Flushometer in 1906, which used pressurized water directly from the supply line for faster recycle time between flushes. The Flushometer is still in use today in public restrooms worldwide. The vortex-flushing toilet bowl, which creates a self-cleansing effect, was invented by Thomas MacAvity Stewart of Saint John, New Brunswick in 1907.[47] Philip Haas of Dayton, Ohio, made some significant developments, including the flush rim toilet with multiple jets of water from a ring and the water closet flushing and recycling mechanism similar to those in use today.

text: The company Caroma in Australia developed the Duoset cistern with two buttons and two flush volumes as a water-saving measure in 1980. Modern versions of the Duoset are now available worldwide, and save the average household 67% of their normal water usage.[48][49]

text: Etymology[edit]

text: This section needs expansion. You can help by adding to it. (June 2013)

text: Water closet[edit]

text: The term "water closet" ("WC") was an early term for an interior or exterior room with a flushing toilet in contrast with an earth closet usually outdoors and requiring periodic emptying as "night soil". Originally, the term "wash-down closet" was used.[50] The term "water closet" was coined in England around 1870. It did not reach the United States until the 1880s. Around this time, only luxury hotels and wealthy people had indoor private bathrooms. By 1890 in the US, there was increased public awareness of the theory of disease and of carelessly disposed human waste being contaminated and infectious.[49]

text: Originally, the term "bath-room" referred only to the room where the bathtub was located (usually a separate room not housing a toilet), but this connotation has changed in common North American usage. In the UK, the terms "bathroom" and "toilet" are used to indicate distinct functions, even though bathrooms in modern homes often include toilets. The term "water closet" was probably adopted because in the late 19th century, with the advent of indoor plumbing, a toilet displaced an early clothes closet, closets being renovated to easily accommodate the spatial needs of a commode.[citation needed] Early indoor toilets had in fact been known as garderobes because they actually were used to store clothes, as the smell of ammonia was found to deter fleas and moths.

text: The term "water closet" now often refers to a room that has both a toilet and other plumbing fixtures such as a sink or a bathtub. Plumbing manufacturers often use the term "water closet" to differentiate toilets from urinals. American plumbing codes refer to a toilet as a "Water Closet" or a "WC". Many European languages refer to a toilet as a "water" or "WC". The Royal Spanish Academy Dictionary accepts "váter" as a name for a toilet or bathroom, which is derived from the British term "water closet". In French, the expression aller aux waters ("to go to the waters") derives from "water closet". "w.-c." is used in the French language, pronounced /ve.se/. Likewise the Romanian word "veceu", pronounced /vetʃeu/, derives from a shortened version of the abbreviation. In German, the expression "Klo" (first syllable of "Kloset") is used alongside "WC"

text: In many Asian countries and China in particular, "WC" is used as a universal name for the toilet; many Chinese people will make a hand sign with the forefinger and thumb held in the shape of a "C" while the remaining 3 fingers of the same hand are extended to represent a "W", thus indicating where they are going or perhaps to explain where someone has gone.[citation needed]

text: Society and culture[edit]

text: Swirl direction myth[edit]

text: It is a commonly held misconception that when flushed, the water in a toilet bowl swirls one way if the toilet is north of the equator and the other way if south of the equator, due to the Coriolis effect – usually, counter clockwise in the northern hemisphere, and clockwise in the southern hemisphere. In reality, the direction that the water takes is much more determined by the direction that the bowl's rim jets are pointed, and it can be made to flush in either direction in either hemisphere by simply redirecting the rim jets during manufacture. On the scale of bathtubs and toilets, the Coriolis effect is too weak to be observed except under carefully controlled laboratory conditions.[51]


document_title: Public housing in Singapore

question_text: when was the first hdb flat built in singapore

root

text: Public housing in Singapore

text: History[edit]

text: Since the founding of modern Singapore, housing in the fledging colony has been concentrated in the city centre, where the early town plans has stipulated ethnic-based districts built on both sides of the Singapore River. Housing in the city was primarily in the form of shophouses where multiple families would live in confined spaces. Housing in the suburban areas were often in the form of either traditional Malay (and occasionally Chinese) villages (Kampongs) or large estates and mansions owned by the Europeans or richer locals.

tag: p

text: SIT under British colonial rule[edit]

text: By the 1920s, chronic housing conditions in downtown Singapore prompted the British colonial government to establish the Singapore Improvement Trust in 1927 to build affordable public housing for the common population of Singapore. The first forms of mass-built public housing thus appeared in Singapore. Still, the SIT managed to build only 23,000 housing units in its 32 years of existence, and was unable to resolve the worsening housing shortage problem.

text: Low construction rates and massive damage from World War II further exacerbated the housing shortage. In 1947, the British Housing Committee Report noted Singapore had "one of the world's worst slums – 'a disgrace to a civilised community'" and the average person per building density was 18.2 by 1947 and high-rise buildings were uncommon. In 1959, the problem of shortage still remained a serious problem. An HDB paper estimated that in 1966, 300,000 people lived in squatter settlements in the suburbs and 250,000 lived in squalid shophouses in the Central Area.[3]

text: HDB post independence[edit]

text: In 1959, in its election campaign, the People's Action Party (PAP) recognised that housing required urgent attention and pledged that it would provide low-cost housing for the poor if it was selected. When it won the elections and formed the newly elected government, it took immediate action to solve the housing shortage. The SIT was changed to the HDB.

text: In February 1960, the Housing and Development Board (HDB) was established to develop public housing and improve the quality of living environment for its residents. Led by Lim Kim San, its first priority during formation was to build as many low-cost housing units as possible, and the Five-Year Building Programme(from 1960 to 1965) was introduced. The housing that was initially built was mostly meant for rental by the low income group.

text: In 1964, the Home Ownership Scheme was also introduced to help citizens to buy instead of renting their flats. Four years later, the government decided to allow people to use their Central Provident Fund savings as downpayment. However, these efforts were not successful enough then in convincing the people living in the squatter settlements to move into these flats.

text: It was after 25 May 1961, the day of the Bukit Ho Swee fire, that HDB's efficiency and earnestness won the people over.

text: The HDB estimated that from 1959 to 1969, an average of 147,000 housing units—80,000 from the current deficit, 20,000 due to the redevelopment of the Central Area, and 47,000 due to population increase—would need to be constructed; an average of about 14,000 a year. However, the private sector only had the ability to provide 2500 per year, and at price levels out of reach of the low-income.[3] The HDB set out to resolve the deficit. Between 1960 and 1965, the HDB built 54,430 housing units. Due to land constraints, high-rise and high-density flats were chosen. By 1965, HDB was able to overcome the worst of the housing shortage by providing low-cost housing to the lower-income group within the planned period of five years.

text: Several reasons contributed to the success of the HDB. Firstly, the HDB received very strong support from the government, which allocated a large amount of funds to public housing. The HDB was also equipped with legal powers such as the power to resettle squatters. The hard work and dedication of Lim Kim San, the first chairman of the HDB, and other members of the board, also contributed to its success.

text: Other providers of public housing[edit]

text: Beside HDB, a small number of flats were built in 1964–1968 by Economic Development Board (EDB) and its successor Jurong Town Corporation (JTC) from 1968 to late 1970s, in Jurong and Sembawang industrial areas.

text: Middle income housing[edit]

text: From 1974 to 1982, the Housing and Urban Development Company (HUDC) built and marketed sandwich housing for middle-income people who did not qualify for HDB flats but could not afford a private property. HDB took over JTC and HUDC in 1982, becoming sole provider of public housing in Singapore, continued building HUDC flats up to 1986.

text: Executive Condominiums[edit]

text: In 1999, the HDB started building executive condominiums, also referred to as EC's. These are public housing units and estates aimed at Singaporeans who do not want a HDB flat but might find private property too expensive. The idea to construct such housing was first mooted in 1995 by then Prime Minister Goh Chok Tong who wanted to provide public housing that was more up-market than the executive flats.[4]

text: Physical organisation and design[edit]

text: Towns and estates[edit]

text: The first public housing built were in SIT Estates, usually located just outside the fringe of Central Singapore, such as Tiong Bahru in the Bukit Merah area. SIT estates also appeared in Queenstown such as the Princess Margaret Estate where construction began in July 1952. In SIT's early plans for the Estate, the new town planning concept was evident with their plans to build housing estates around a commercial centre.[5]

text: When the HDB took over in 1960, they fully adopted the new town planning concept on a large scale, building partial towns from scratch in locations all around Singapore. Queenstown thus became the SIT's model of its version of a New Town, and they developed this further in Toa Payoh which was the first town to be built entirely from the ground up by the HDB. Initially, gigantic developments, sometimes known as Minicities, were built in areas in the city centre, Changi Point, Lim Chu Kang, Farrer Park and Seletar, and in larger areas such as in Bukit Timah and Marine Parade.

text: These have since been halted in favour of concentrating public housing developments only in minor HDB towns. Over the years, the HDB began to reorganise the larger estates and amalgamate them into "HDB Towns", as has been done in Bukit Merah, Geylang and Kallang/Whampoa, while Bukit Timah and Marine Parade remained as estates. Simei, sometimes referred to as an estate and a new town, has since been amalgamated into Tampines. There are now officially 23 "HDB Towns" and three "Other Estates".

text: While most towns are compact and are contiguous, some towns, especially those incorporating existing developments and the reorganised estates may appear scattered. Two of the best examples of discontinuous new towns built over existing developments include Bishan and Serangoon. Hougang also has significant areas of non-public housing use. The reorganised "new towns" of Bukit Merah, Geylang and Kallang/Whampoa are similarly fractured in some places. On the other end of the scale, Jurong East, Jurong West, Tampines, Toa Payoh and Yishun have very little private housing and no landed properties, while towns like Ang Mo Kio, Choa Chu Kang, Clementi, and Woodlands have only small pockets of landed properties.

text: Based on the new town concept, each HDB town is designed to be self-sustainable. Helmed by a hierarchy of commercial developments, ranging from a town centre to precinct-level outlets, there is no need to venture out of town to meet the most common needs of residences. Employment can be found in industrial estates located within several towns. Educational, health care, and recreational needs are also taken care of with the provision of schools, hospitals, parks, sports complexes, and so on.

text: HDB towns are typically sub-divided into neighbourhoods, with most neighbourhoods served by a neighbourhood commercial centre. Depending on the size of the town, there can be as many as nine neighbourhoods, to as little as two. Except for the older towns, estates and consolidated towns, most towns use the first digit of their block numbers to indicate the neighbourhood in which the block is located in.

text: Each neighbourhood is in turn composed of multiple precincts, which are built on the concept of promoting communal exchanges and which are more secure. While older precincts may merely involve dividing rows of identical blocks in relatively close proximity without any other real interaction with each other, newer precincts are designed to physically envelop a common space, or centred around some kind of communal facility such as a multi-storey carpark. While precinct boundaries may be difficult to physically distinguish in older precincts, they are usually obvious in newer precincts through the physical layout of the block and their unique architectural design. Newer precincts (and upgraded older precincts) also often adopt fanciful names reminiscent of private developments to lend an air of class and belonging, although these names are often not used in reality since they are sometimes not displayed and are not part of official addresses.

text: Precincts[edit]

text: Public housing precincts in Singapore are clusters of public housing blocks arranged as a single unit. Comprising an average of 10 blocks per precinct, they are collectively grouped into up to nine neighbourhoods per new town.

text: History[edit]

text: The Housing and Development Board, the sole public housing planner, designer and builder in the city-state, adopted the precinct concept in 1978, based on its understanding that social interaction and community bonding can be optimised in a smaller planning unit compared to a full neighbourhood. In addition, precincts are expected to evoke a stronger sense of security, although they are not physically fenced, and do not restrict movements for residents or outsiders in any physical way.

text: Tampines thus became the first new town to be planned according to this model in 1980. This concept persisted in subsequent application of the model in other towns through to the present, although some modifications are noted, particularly in terms of precinct size and physical configuration. The increased usage of multi-storey carparks also allow flexibility in the provision of open spaces for each precinct, and the configuration of blocks to separate human and vehicular traffic.

text: While older new towns were not built according to the precinct concept, they were, nonetheless, often planned and built in batches otherwise similar to precincts. Major town redevelopment and upgrading plans such as the Main Upgrading Programme and the Interim Upgrading Programme in older estates such as in Queenstown, Toa Payoh, and Bukit Merah from the 1920s has involved the enhancement of the precinct concept, including the physical upgrading to collective groups of blocks, re-configuration of public spaces around them, and often includes the christening of names to these estates. In other cases, old groups of blocks are completely demolished and rebuilt under the Selective En bloc Redevelopment Scheme, accelerating the evolution of these towns towards the precinct concept.

text: Block design[edit]

text: Each public housing block is considered a vertical community, with common area built into the design to promote social interaction. Void decks, a term unique to Singapore, refers to the first level which are often left devoid of housing units, hence the word "void". These open, sheltered spaces are intentionally left empty to provide convenient spaces for communal activities such as weddings, funerals, parties, bazaars and even as polling stations. Selected blocks would feature a single stand-alone shop, often referred to as "Mamashops" to provide convenient doorstep service. Other common permanent facilities built in void decks may include Residential Committee facilities and offices, kindergartens, medical centres, Neighbourhood Police Posts, fire posts and so on.

text: Also common especially in older flats are the common corridors, some of which may run across the length of slab blocks. Considered public property, they have rules preventing home owners from occupying and restricting movement, with the exception of units at far ends of corridors who may purchase and incorporate parts of the corridor into their units from the HDB. While these corridors are welcome for being the default interaction areas for neighbours and their children, and the added sense of security due to their open-nature, issues of privacy can crop up, resulting in more contemporary blocks featuring far fewer units per corridor. Larger units such as 5-room flats are also commonly housed in "Point blocks", which feature only four units per floor.

text: The slanting roofs of several blocks in Potong Pasir were considered revolutionary and became instant landmarks for the estate till this day. Today, HDB blocks tend to amalgamate the point and slab block designs, featuring taller blocks but with slightly more units of about 6–8 units per floor. New blocks nowadays tend to be around 40-storeys high. As of 2010, The Pinnacle@Duxton, is the highest HDB flat in Singapore, with seven connected 50-storey towers, totalling to 1,848 units.

text: The façades of public housing blocks has also evolved over time. While the SIT blocks occasionally featured Art Deco designs, the first HDB blocks were typically brutalist. After the initial rush to mass-build flats in the 1960s however, varying façades began to appear in subsequent decades, initially only through subtle variations such as coloured tiles, but which became full-scaled multi-coloured paintwork complete with bright motifs from the 1990s. After several elaborate designs, some of which subsequently presented logistical headaches during maintenance, more subdued and contemporary designs began to emerge from the 2000s.

text: Ownership and rental[edit]

text: More than 80% of Singapore's population live in HDB flats. HDB Flats in Singapore are sold on a 99-year lease agreement. The remainder are rental flats reserved for those who are unable to afford to purchase the cheapest forms of public housing despite financial support.

text: Singapore maintains a quota system of ethnicities through the Ethnic Integration Policy.[6] By ensuring that each block of units are sold to families from ethnicities roughly comparable to the national average, it seeks to avoid physical racial segregation and formation of ethnic enclaves common in other multi-racial societies. In practise, while ethnic enclaves were avoided, some towns remained traditionally popular for specific ethnic groups. For instance, towns such as Bedok, Tampines and Woodlands have a slightly larger proportion of ethnic Malays above the national average.

text: Partly in response to public sentiment against the alleged formation of "PR enclaves", where some flats appeared dominated by PRs from a single nationality, the HDB introduced the Singapore Permanent Resident Quota which took effect on 5 March 2010. Other than Malaysian PRs which were excluded from the quota due to their "close cultural and historical similarities with Singaporeans", all other PRs were subject to a cap of 5% PR households per block.[7]

text: New flats[edit]

text: The primary acquisition avenue is through the purchase of new flats directly from the HDB. Over the years, various forms of sale programmes has been in place, with the current mode of sale known as the Build-To-Order (HDB) programme launched in 2001. This is run alongside the Sale of Balance Flats (SBF) exercise which handles the sale of balance flats from earlier BTO exercises, unsold SERS replacement flats and flats which were repossessed by the HDB. The sale of EC and DBSS flats are conducted separately by the respective private developers.

text: Under the current sales schemes, successful applicants for new BTO flats typically have to wait several years before moving in while the flats were built, since the commencement of construction can only occur when the BTO successfully attains 65~70% sales. Applicants who wish to move in immediately or earlier thus have to participate in the SBF exercise (although some flats may still be under construction) or go for Resale Flats.

text:
HDB Sale of Flats programmes

Programmes
Abbrev
Start
End
Remarks

Registration for flat
RFS
1980s
Feb 2002
Any surplus units from BTOs, balance BEs or
HDB buy-back schemes through balloting method

Walk-in Selection
WIS
Mar 2002
Feb 2008

Sale of Balance Flats
SBF
Apr 2007
–

Selective En bloc Redevelopment Scheme
SERS
Aug 2016
–
Buying a new flat as replacement for a flat in a block selected for redevelopment

Balloting Exercise
BE
Aug 1995
–
Only available for initial large surplus units of SERS

Build to Order
BTO
Apr 2001
–
Buying a new flat built by HDB with a waiting period of 4 years

Design, Build and Sell Scheme
DBSS
Oct 2006
–
Buying a new flat build by private developer and maintained by HDB as public housing

Executive Condominium
EC
Jan 1999
–
Buying a new condominium built by private developer and sold under eligibility conditions similar with public housing

tag: table

text: There are a number of eligibility conditions in order for a flat to be purchased. A buyer must be a Singaporean citizen, or P.R. and be 21 years of age and have a family. Singles below 35-years of age, and non-citizens are not allowed to purchase new HDB flats. Other requirements concern household status, time requirements, income and other special requirements.[8] The apartment flats are typically sold on a 99-year lease.

text:
Eligibility to Acquire New Flats

New HDB flat
New DBSS flat
New EC
New 2-Room Flexi Flat

Citizenship
Applicant: Citizen
Family nucleus: At least another citizen or PR
Applicant: Citizen
Joint Applicant (if any): Related must be a Citizen; Non-related must be Citizen or PR

Age
21 years old
21 years old (35 for joint singles)
55 years old (Joint Applicant, if any: Related=21 years old; Non-related=35 years old

Family nucleus
Any of the following combinations:
• Applicant+Spouse+Children (if any)
• Applicant+Parents+Siblings (if any)
• Widowed/divorced applicant+Children under legal custody
• Applicant+fiance/fiancee
• Orphaned applicant+unmarried siblings
Any of the following combinations:
• Applicant+Spouse+Children (if any)
• Applicant+Parents+Siblings (if any)
• Widowed/divorced applicant+Children under legal custody
• Applicant+fiance/fiancee
• Orphaned applicant+unmarried siblings
• Orphaned applicant+single unrelated orphan
• Single applicant+another single person
Either:
• Applicant+Spouse
• Unmarried, divorced or widowed applicant

Gross monthly household income ceiling
2-room (non-mature towns/estates): $2,500
2-room (mature towns/estates): $6,000
3-room (non-mature towns and estates): $6,000
3-room (mature towns and estates/Premium), 4-room and above (all estates): $12,000 ($18,000 for extended families)
$12,000 ($18,000 for extended families)
$14,000 with tiered subsidies
$12,000

text: With effect from 24 August 2015, the HDB revised upwards the monthly household income ceiling for the purchase of new flats from $10,000 to $12,000.[9] The $10,000 and $8,000 income ceilings were implemented on 15 August 2011 [10] and 1994,[11] respectively.

text: Those are the priority schemes available when applying for a flat from HDB:[12]

text:
Priority Schemes available[13]ㄑ

Type of flat
Type of scheme

New flats from HDB
Multi-Generation Priority Scheme (MGPS)

Married Child Priority Scheme (MCPS)

Third-Child Priority (TCP) Scheme

Tenants Priority Scheme (TPS)

Parenthood Priority Scheme (PPS)

Assistance Scheme for Second-Timers (Divorced/Widowed Parents) [ASSIST]

Senior Priority Scheme (SPS)

DBSS Flats from Developers
Married Child Priority Scheme (MCPS)

Third-Child Priority (TCP) Scheme

Executive Condominium (EC) from Developers
Priority Schemes are not applicable for Executive Condominium.

text: From July 2013, two new groups had been allowed to purchase flats directly from HDB. The first group is single Singaporeans aged 35 and above with an average monthly income not more than $5,000. The other group is Singaporean-Foreigner couples. However the flat type that both groups can buy is restricted to two-room HDB flats in non-mature estates.[14]

text: Resale flats[edit]

text: Existing flat owners are allowed to sell their flats on the open market to any eligible buyer at a mutually agreed price. While the HDB does not regulate these prices, the buyer and seller must declare the true resale price to the HDB. In addition, most flat owners may only sell their flat if they have met the Minimum Occupation Period (MOP) requirement, which was introduced to help reduce speculative activities. In 2010, these requirements were lengthened to help cool the heated property market at that time.

text:
Minimum Occupation Period[15]

Flat type
MOP

1-Room/HUDC flat
Nil

Direct-purchase HDB/DBSS/Subsidised Resale Flat
5 years from date of purchase

SERS flat
With portable SERS rehousing benefits: 5 years from date of purchase
Without portable SERS rehousing benefits: 7 years from date of selection; 5 years from date of purchase

Non-subsidised Resale Flat
1–5 years from date of resale dependent on sale date and type of loan taken (if any)

text:
HDB Sale of Flats programmes

Programmes
Abbrev
Start
End
Remarks

Registration for flat
RFS
1980s
Feb 2002
Any surplus units from BTOs, balance BEs or
HDB buy-back schemes through balloting method

Walk-in Selection
WIS
Mar 2002
Feb 2007

Sale of balance flats
E-Sale
Apr 2007
–

Balloting exercise
BE
Aug 1995
–
Only available for initial large surplus units of SERS

Build to order (HDB)
BTO
Apr 2001
–
Buying a new flat with a waiting period of 4 years

Design, Build and Sell Scheme
DBSS
Oct 2006
–
Buying a new condominium design flat build by private developer

text: Buyers are also subject to a set of eligibility conditions.

text:
Eligibility to Buy Resale Flats[16]

Condition
Public Scheme
Fiancé(e) Scheme
Single Singapore Citizen Scheme
Joint Singles Scheme
Non-Citizen Spouse Scheme
Non-Citizen Family Scheme
Orphans Scheme
Conversion Scheme

Citizenship
Applicant: Citizen
Family nucleus: At least another citizen or PR
Applicant and fiancé(e): Citizen or PR
Applicant: Citizen
Applicant: Citizen
Unmarried sibling: Citizen or PR
Applicant: Citizen
Family nucleus: At least another citizen or PR

Age
21 years old
Singles/Divorcees: 35 years old
Widowed/Orphan: 21 years old
Spouse's social visit pass >6 months:21 years old
Spouse's social visit pass <6 months:35 years old
21 years old

Family nucleus
Any of the following combinations:
• Applicant+Spouse+Children (if any)
• Applicant+Parents+Siblings (if any)
• Widowed/divorced applicant+Children under legal custody
Applicant+fiancé(e)
Applicant only
Applicant+up to three other single joint applicants
Applicant+non-citizen spouse
Any of the following combinations:
• Applicant+non-citizen parents+non-citizen siblings (if any)
• Widowed/divorced applicant+non-citizen children under legal custody
Orphaned applicant+unmarried siblings
Any of the following combinations:
• Applicant+Spouse+Children (if any)
• Applicant+Parents+Siblings (if any)
• Widowed/divorced applicant+Children under legal custody

Gross monthly household income ceiling
No income ceiling unless applying for CPF Housing Grant and/or an HDB Loan

text: Pricing[edit]

text: Pricing of public housing flats are typically cheaper than privately built developments. For example, an HDB 4-room flat depending on age, environment and surrounding amenities can have a sale value of between S$200,000 to above S$300,000 and an HUDC Executive maisonette above S$500,000. However, in contrast a privately developed condominium type housing can cost as much as S$1,000,000 and above.

text:
List of average new & resale prices of Housing Development Board flats

Period
Room type
Internal
New
Resale
Remarks

sq m (Avg)
S$ (Avg)
S$ (Avg)

1970s
3-room
60
$15,000
–
Construction cost-based pricing approach

4-room
75
$20,000
–

5-room
95
$30,000
–

1980s sharp rise@81 (a)
3-room
65
$50,000
–
Construction cost-based and
land-based pricing approach

4-room
90
$80,000
–

5-room
115
$110,000
–

Executive
140
$140,000
–

1990s sharp rise@93 till 97
3-room
70
$120,000
$200,000
Construction cost-based and
market land-based pricing approach

4-room
95
$170,000
$270,000

5-room
125
$230,000
$350,000

Executive
145
$280,000
$420,000

2000s (b)
3-room
65
$110,000
$150,000

4-room
90
$180,000
$230,000

5-room
110
$240,000
$290,000

Executive
130
$300,000
$350,000

2007s sharp rise@2008 (c)
3-room
65
$140,000
$200,000
Construction cost-based and
market resale-based pricing approach

4-room
90
$230,000
$300,000

5-room
110
$290,000
$370,000

Executive
130
$350,000
$450,000

2010 (d)
3-room
65
$291,000

Median house price (including approximate transaction cost)

4-room
90
$376,300

5-room
110
$448,700

Executive
130
$535,900

(a) Average floor sizes was increased for new flat built from year 1981.
(b) Average floor sizes was decreased for new flat built from year 2000 but with premium design finishing except 3-rm unit.
(c) Pricing increased in year 2008 are also due to rising construction cost from sand and concrete supply.
(d)Straits Times, 4 August 2010

text: Maintenance and renewal[edit]

text: Maintenance of the HDB's approximately 900,000 units largely falls under the Town Councils, which are not part of the HDB but which are formed under the Town Councils Act primarily with the purpose of maintaining the common areas of HDB flats and estates. Common areas would include the common corridors, void decks, lifts, water tanks, external lighting and the open spaces surrounding the estates, which are managed, maintained and improved on by the respective Town Councils. These Town Councils are formed by the respective political constituencies and do not necessarily follow HDB Town boundaries, hence a single HDB Town may be managed by multiple Town Councils.

text: Rental flats, on the other hand, are maintained directly by the HDB to ensure serviceability for the next occupant. The HDB is also the direct authority overseeing home renovation works, whereby while home owners engage third-party contractors, the HDB imposes strict renovation rules to ensure no structural damage and adherence to noise control during renovation works. The HDB also approves renovation contractor registrations to enforce quality control.

text: Large-scale improvement works to existing public housing developments were carried out in the form of various programmes under the Estate Renewal Strategy, beginning with the Main Upgrading Programme (MUP) since 1990. These help to bring common facilities up to standards with newer developments, and in some cases, to offer some improvements to individual units, such as the addition of reinforced bomb shelters which can double-up as an additional room during non-emergency periods.

text: To date, close to 800 precincts has benefited from these schemes. While the majority of precincts were improved upon, some precincts were completely redeveloped under the Selective En bloc Redevelopment Scheme to better maximise the use of land. As 2016, 80 sites has been affected since the Scheme was introduced in 1995, affecting over 33,000 residential units.[17]

text:
HDB upgrading programmes

Programmes
Abbrev
Start
End
Remarks

Main Upgrading Programme
MUP
Jul 1990
Apr 2011
Interior upgrading programmes for flats built up to 1986, and
HIP which have not undergone MUP, with added optional improvements

Home Improvement Programme
HIP
Aug 2007
–

Interim Upgrading Programme
IUP
Aug 1993
Aug 2002
The common areas of a precinct were upgraded, landscape upgrading programmes stopped in flavour of IUP Plus

Selective En bloc Redevelopment Scheme
SERS
Aug 1995
–
Announced in August 1995, it is a scheme that rejuvenates the older low-rise blocks (prior to 1996) into the high-rise blocks.

Lift Upgrading Programme
LUP
Sep 2001
–
Direct level access to lift for flats built up to 1990,
IUP Plus – a combination of two programmes, IUP and LUP

Interim Upgrading Programme Plus
IUP Plus
May 2002
Dec 2014

Neighbourhood Renewal Programme
NRP
Aug 2007
–
This would include MUP/HIP (interior) and IUP Plus (landscape) as it focus on block and neighbourhood improvements

Selective Lift Replacement Programme
SLRP
Sep 2014
–
Replace about 750 old lifts with modern lifts that come with more energy-efficient motors,
vision panels and infra-red doors with motion safety sensors for added energy efficiency, safety and security