A flush toilet (also known as a flushing toilet, flush lavatory or
water closet (WC)) is a toilet that disposes of human excreta (urine
and feces) by using water to flush it through a drainpipe to another
location for disposal, thus maintaining a separation between humans
and their excreta. Flush toilets can be designed for sitting (in which
case they are also called "Western" toilets) or for squatting, in the
case of squat toilets. The opposite of a flush toilet is a dry toilet,
which uses no water for flushing.
Flush toilets usually incorporate an "S", "U", "J", or "P" shaped bend
(called a trap, such as P trap or S trap) that causes the water in the
toilet bowl to collect and act as a seal against sewer gases (trapping
the gases). Since flush toilets are typically not designed to handle
waste on site, their drain pipes must be connected to waste conveyance
and waste treatment systems. When a toilet is flushed, the wastewater
flows into a septic tank or sewage system and from there to a sewage
A flush toilet is different from a urinal, which is designed to handle
only liquid waste; or from a bidet, which can be used for cleansing of
the excretory areas after toilet use.
1.1 Mechanical flush from a cistern
1.2 Manual flush (pour flush)
3 Water usage
4 Flushing mechanism
4.1 Tank fill valve
4.2 Tank style with flapper-flush valve
4.3 Tank style with siphon-flush valve
4.3.1 Dual flush toilets
4.4 Tank style with high-pressure or pressure-assist valve
4.5 Tankless style with high-pressure (flushometer) valve
4.6 Flushing with non-potable water sources
5 Bowl design
5.1 Siphoning toilet
5.2 Double trap siphonic toilet
5.4 Washout toilet
5.5 Shelf style (Flachspüler)
5.6 Simple flush toilets in old railcars
6 Squat toilets
7 Low-flow and high-efficiency flush toilets
7.1 US standards for new toilets
8 Maintenance and hygiene
9.1 Ancient flush toilet systems
9.2 Development of the flush toilet
9.3 Industrial production
9.4 Spread and further developments
10.1 Water closet
11 Society and culture
11.1 Swirl direction myth
12 See also
14 External links
A flush toilet bowl during the flushing action
Typical sound of a flush toilet
The focus of this article is a flush toilet that uses a mechanical
flush from a water cistern that is above the toilet.
Mechanical flush from a cistern
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.
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.
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
Manual flush (pour flush)
Another variant of the flush toilet is the pour-flush toilet. 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. 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.
Toilet with an elevated cistern of water and a chain attached to the
tank to release water and flush the waste away
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
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.
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.
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.
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.
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
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.
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.
The bowl drain is visible at the rear of the bowl, connected to the
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.
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
Some users do not flush their toilets after urination, in order to
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. In other designs, a segmented
flush pushbutton is used; pressing the smaller section releases less
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
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:
Tank fill valve
The ballcock or float valve is often used to regulate the filling of a
tank or cistern. When the fluid level drops, the float descends,
levering the valve opening and allowing more fluid to enter. Once the
float reached the 'full' position, the arm presses the valve shut
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.
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.
One type of concentric float valve. The concentric float valve opens
when the fluid level is low, allowing more fluid to enter (Figure 1).
When the fluid level returns to the full level, the valve is shut
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.
Tank style with flapper-flush valve
A traditional gravity toilet tank concluding the flush cycle. As the
water level in the tank drops, the flush valve flapper falls back to
the bottom, stopping the main flow to the flush tube. Because the tank
water level has yet to reach the fill line, water continues to flow
from the tank and bowl fill tubes. When the water again reaches the
fill line, the float will release the fill valve shaft and water flow
1. float, 2. fill valve, 3. lift arm, 4. tank fill tube, 5. bowl fill
tube, 6. flush valve flapper, 7. overflow tube, 8. flush handle, 9.
chain, 10. fill line, 11. fill valve shaft, 12. flush tube
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").
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
Tank style with siphon-flush valve
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. 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.
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.
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.
Dual flush toilets
Main article: Dual flush toilet
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.
Tank style with high-pressure or pressure-assist valve
Sloan pressure vessel
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.
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
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. This design is also
much quieter than other pressure-assist or flushometer toilets.
Tankless style with high-pressure (flushometer) valve
Main article: Flushometer
In 1906, William Sloan first made his "flushometer" style toilet flush
valve, incorporating his patented design, available to the public.
The design proved to be very popular and efficient, and remains so to
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.
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.
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).
Flushing with non-potable water sources
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), Gibraltar, and Avalon, California, United States.[citation
Three styles of toilet:
Figure 1. The Washdown style
Figure 2. The Wash-out style
Figure 3. The Reverse Bowl or Shelf Style
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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).
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
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.
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.
Double trap siphonic toilet
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
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.
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).
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. 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.
Shelf style (Flachspüler)
A shelf-style toilet which holds fecal matter above the water until
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
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. 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
Simple flush toilets in old railcars
This type of toilet is used on most older style Russian trains, made
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.
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.
Example of a squat toilet in Rome, Italy
Main article: Squat toilet
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
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
In India, the "Anglo-Indian" design allows the same toilet to be used
in the sitting or the squatting position.
Low-flow and high-efficiency flush toilets
Low flush toilet and Dual flush toilet
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. 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.
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.
US standards for new toilets
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
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). 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.
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. 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. Some HETs are pressure-assisted (or power-assisted or
pump-assisted or vacuum-assisted).
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
Environmental Protection Agency uses a MaP score of
350 as the minimum performance threshold for HETs. 1.6 gpf toilets
are also sometimes referred as ULF (Ultra Low Flow) toilets.
Methods used to make up for the inadequacies of low flow toilets
include using thinner toilet paper, plungers, and adding extra
cups of water to the bowl manually.
Maintenance and hygiene
If clogging occurs, it is usually the result of an attempt to flush
unsuitable items, or too much toilet paper. 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
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. 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.
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
Studies have shown aerosol droplets are produced by flushing the
toilet, that enter the air of the room. No proven cases of
infection have been found, and the risk is unknown. A
Fecal-oral route was demonstrated for aerosol droplets that are
produced by flushing the toilet. These aerosols are also called
See also: History of water supply and sanitation
Ancient flush toilet systems
Dholavira Sophisticated Water Reservoir, evidence for hydraulic sewage
systems in the ancient Indus Valley Civilization.
Toilets that used water were used in the Indus Valley Civilization.
The cities of
Mohenjo-daro had a flush toilet in almost
every house, attached to a sophisticated sewage system. See also
Sanitation of the Indus Valley Civilisation. They also appear in
Knossos and Akrotiri of the ancient
Minoan civilization from the 2nd
Primitive forms of flush toilets have been found to exist since
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. The village's design used a
river and connecting drainage system to wash waste away.
Similar toilets were in use throughout the
Roman Empire from the 1st
through 5th centuries AD. A very well-preserved example are the
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.
Development of the flush toilet
Alexander Cumming's 1775 patent for the S-trap, which laid the
foundations for the modern flush toilet.
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. 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.
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
Alexander Cumming in 1775, and still in use today. This
device uses the standing water to seal the outlet of the bowl,
preventing the escape of foul air from the sewer. 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".
Joseph Bramah's improved version was the first practical flush toilet.
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.
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. The design was arguably the first
practical flush toilet, and production continued well into the 19th
century, used mainly on boats.
Thomas William Twyford
Thomas William Twyford was one of the leading marketers of flush
toilets in their first boom of popularity after the Great Exhibition
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
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
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.
George Jennings trademark on his manufactures.
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.
Another pioneering manufacturer was Thomas William Twyford, who
invented the single piece, ceramic flush toilet. 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. 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.
Flush toilets were widely available from the mid to late 19th century.
Thomas Crapper did not invent the flush toilet, he was a
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. The
modern pedestal "flush-down" toilet was demonstrated by Frederick
Humpherson of the Beaufort Works, Chelsea,
England in 1885.
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.
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. Crapper popularized the siphon system for emptying the
tank, replacing the earlier floating valve system which was prone to
Spread and further developments
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.
In America, the chain-pull indoor toilet was introduced in the homes
of the wealthy and in hotels, soon after its invention 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.
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. 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.
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.
This section needs expansion. You can help by adding to it. (June
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. 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.
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. 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.
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"
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.
Society and culture
Swirl direction myth
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
Toilets in Japan
Thomas Maddock, started the American indoor toilet industry
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