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What should I know about toilets & urinals?

Written by Pieter Paul de Jongh
Saturday, 27 November 2010 12:42

There are several designs of toilets. These are close coupled, low level, high level, back to wall, and wall- hung.

• Close coupled is floor mounted with the cistern against the wall and resting on the back of the pan.

• Low Level toilets are floor mounted with a small pipe connecting the cistern to the pan. A High Level toilet has a longer pipe connecting the cistern and pan.

• Back to Wall toilets are popular in commercial washrooms. The cistern is hidden and installed behind the wall.

• Wall-hung toilets are wall mounted on brackets or a WC frame. A frame is required when the wall is not solid masonry. This design is a common space saving design and it also makes for easier cleaning.


As with many inventions, the flush toilet did not suddenly spring into existence, but was the result of a long ‘chain’ of minor improvements.Therefore, instead of a single name and date, here follows a list of significant contributors to the history of the device.

Circa 26th century BC: Flush toilets were first used in the Indus Valley Civilisation.

• 1st to 5th centuries AD: Flush toilets were used throughout the Roman Empire.

• 1596: Sir John Harrington is said to have invented 'The Ajax', a forerunner to the modern flush toilet, for Elizabeth I of England, who would not use the contraption because it made too much noise. The design had a flush valve to let water out of the tank, and a wash-down design to empty the bowl.

• 1775: Alexander Cummings invented the S-trap, still in use today, which uses standing water to seal the outlet of the bowl, preventing the escape of foul air from the sewer.

• The first popularised water closets were exhibited at The Crystal Palace and these became the first public toilets. They had attendants dressed in white and customers were charged a penny for use. This is the origin of the phrase "To spend a penny".

• 1880s: Thomas Crapper's plumbing company built flush toilets. After the company received a royal warrant, Crapper's name became synonymous with flush toilets. Although he was not the original inventor, Crapper popularised the siphon system for emptying the tank, replacing the earlier floating valve system which was prone to leaks. The similarity between Crapper's name and the much older word crap is merely a coincidence.

Pan or Bowl

Pans can be exposed or hidden which impacts on how they are fitted. Pans are either bolted to the floor or are fastened onto the floor. Never cement a WC Pan to the floor!


A low level toilet, reminiscent of a traditional style, is where the cistern is fixed to the wall above the toilet pan and is connected by a short flush-pipe. The cistern is most likely operated by a lever on the front of the cistern, and the flush will probably be more aggressive than that in a close-coupled toilet because of the extra height of the cistern and the help that gravity gives. Flush pipes are usually available in metal-plated finishes as well as plastic so that the bathroom can have a more attractive and co-ordinated look.


Close coupled W/Cs, sometimes referred to as W/C combinations, comprise an attached cistern and toilet pan. They do not require any external or hidden plumbing and come complete with the internal flush mechanism of the cistern and in most cases, the toilet seat and cover.

Wall-hung Toilet

Wall-hung toilet - suspended or hanging toilet - is fixed tight up to the wall but does not reach to the floor. The cistern is concealed within the unit or inside the wall or behind a panel and connects to the pan by a short flush pipe. A Flushmaster could be used instead of a cistern.

Wall-hung toilets were initially designed for commercial applications but have become increasingly popular in domestic situations as design influences have changed, and people have looked to maximise the space they have available. They tend to be quite expensive in comparison with other toilet designs.

Installation of wall-hung toilets is a little more problematic than with standard back to wall toilets and there are many methods of fastening them to the wall. A special bracing frame which includes the fastenings for the cistern and pipes is fitted inside the wall or behind a panel. The pan is bolted to the frame. Simpler brackets for the various shapes and brands of pan are available. Some brackets include rods that stick out from the wall on which the pan hangs.

Back to Wall Toilets

A back to wall pan fits tight up to a furniture unit or false or stud wall. A cistern concealed within the unit or boxed in the wall connects to the pan by a short flushpipe which, like the cistern, is most likely plastic as none of it can be seen. The flush is operated by a lever to the front or by a push-button on the top.

Most furniture units come with a removable panel or lid so that one can access the cistern fairly easily should there be a problem. So if installing a back-to-wall pan against a stud wall, consider future access here too.

High Level Toilets

A high level toilet is probably the most traditional looking toilet available. With a cistern mounted high on the wall and connected to the pan by a long flush- pipe, the flush is powerful and operated by a pull-chain and handle. The flush- pipe can be complemented with decorative support brackets under the cistern and is available in different metal-plated finishes for an attractive and well-coordinated look.

Wall-hung Toilets

A wall-hung toilet, suspended or hanging toilet, is fixed tight up to the wall but does not reach to the floor, which makes it very easy to clean underneath. To make the pan solid and stable, use a steel support frame hidden within a furniture unit or boxed within a false or stud wall. This also allows for a certain amount of flexibility in the height at which the pan is set. A cistern concealed within the unit or wall connects to the pan by a short flush pipe and may be operated by a lever to the front, or a push-button to the top.

If installing a wall-hung pan to a stud wall, it may be necessary to incorporate a shelf area to locate the push-button flush.

Squat Proponents of squat toilets argue that:

• It is less expensive and easier to clean and maintain.

• It does not involve any contact between the buttocks and a potentially unsanitary surface.

• The splashing of water on the buttocks after a heavy defecation does not occur.

• Squatting might help to build the required pressure more comfortably and quickly.

Arguments against squat toilets

• A common argument against the squat toilet is that if toilet paper is used where there is no flushing system installed, it is easy for the inexperienced user to clog the toilet. Those unfamiliar with the squat toilet should be sure to ask the location of the flushing bucket before attempting use. These buckets flush the toilets manually like a tank would.

• Squat toilets are not accessible to handicapped or disabled persons; to use squat toilets a person must have complete use and mobility of both their legs and arms, which would hinder many people with physical challenges.

• When feral matter drops into the toilet the odour may increase as opposed to a western toilet which traps the odour under water.

• People tend to lose their balance when using a squat toilet.

Nursery / Junior Pans

There is a small range of products for young children.


Historically, cisterns are the large ceramic ‘boxes’ on the wall behind the toilet bowl. These are known as ‘open’ cisterns.

A modern tendency is to conceal the cistern into the wall or behind a panel.


An average toilet cistern uses from 6 to 9 litres of water for every flush. As it is not necessary to use this amount of water every time the toilet is used, billions of litres of water are wasted every year. This is expensive both in terms of cost to the householder and water conservation.

Some homeowners place a brick in the cistern to reduce the amount of water used. This is hazardous: should the brick fall over when the cistern is empty, it can punch a hole in the tank. It will also interfere with outflow. It is safer to reduce the amount of water in the tank by bending the float arm downwards.

If you cannot hold the rod and bend it in the cistern, remove it by releasing the split-pin holding it into the valve, and bend it over a table-edge. Reinstall the rod.

While conservation of water is an admirable goal, even the best 6L close-coupled (tank mounted directly on the bowl) toilets have a tendency to either become clogged themselves, or have the drain pipes beyond them become clogged due to insufficient velocity of the waste matter.

Flush Systems

Imported modules often have built-in flush mechanisms, but the trend is towards modular flush systems. Cisterns are designed to accept a wide range of flush mechanisms.

1. Side Flush – only provides a standard flush

2. Top Flush - besides the standard flush, a top flush could also be a Split/Dual/Double flush option.

3. ‘Automatic flush’ refers to a triggering mechanism, rather than a water propulsion mechanism, although is usually implemented together with direct flush systems. Autoflush systems, as the name suggests, flush automatically once the user has left. Typically, an override button is provided if the user wishes to trigger flushing earlier or, when the system has true mechanical manual override, it can be pushed if the power source to the flush valve has failed. In retrofit installations, a self-contained battery-powered or hardwired unit can be added to an existing manual flushometer, which can automatically flush when a user departs.

4. There are two main kinds of machine vision systems used for sensor operated flush: passive and active. Passive systems such as passive infrared (PIR) see the heat radiation of the user. Active vision systems provide a source of electromagnetic energy (radar, infrared, or the like) and see reflected energy from the user.

5. Dual Flush - Flushing a toilet each time throws water down the drain. In the early 20th century, each flush used 18 litres of water. Towards the end of that century, a typical flush drained away half of that - 9 litres.

A flush is designed to carry solid waste matter. Liquid waste does not require the same volume. Dual flush systems allow the user to select a smaller flush for the latter circumstance. The lesser flush uses only 3 litres.

A split button indicates the dual flush option. The smaller button section naturally is the smaller flush. The split flush button is usually fitted in to the top cover of the cistern, but may be in a panel on the wall behind the toilet.

6. Flushometer - This invention relates generally to devices using the principle, which says that the same pressure generates more force over a small surface area than over a larger surface area. This principle comes into play when blowing up a balloon. The balloon’s surface area is small to begin with, requiring a more forceful blow. As it inflates and it’s surface area increase, less blowing effort is required.

In the flushometer, a diaphragm is pressed down onto the supply pipe to shut off the water. The water pressure exerted over a small area pushes it down. The water is also applied on the other side of the diaphragm, but to a larger surface area, wanting to push it off the supply pipe and thus allow water to flow. But it cannot do this, because the pressure on the other side of the diaphragm is greater.

By pressing the flush lever, the pressure in the smaller area is released and the larger area pushes the diaphragm away from the supply pipe and water begins to flow. The lever having been released, water also begins to fill the small area and gradually pushes the diaphragm closed.

Even with a diagram, it is difficult to imagine how this happens. The best way understand the process is to open a flushometer and take a look.

The Flush Test

The installation of large numbers of toilets in buildings like sports stadiums has led to a test which is commonly performed before the final release of such a project, which is called ‘The Flush’. It entails stationing individuals in each restroom in the facility -- in large installations this can amount to 100-400 people -- and cueing them all by radio to flush their toilets as close to simultaneously as possible.

Toilet Waste Drainage

The pipe carrying the waste from the toilet pan to the sewerage main has a bend in it which traps water in it so that smells from the sewers cannot enter the dwelling. The most common is the P- trap which is used where the drainage pipe exits the room through the wall. In situations where the drainage pipe exits through the floor, an S¬trap is used.


Urinals are primarily aimed at the commercial market. They are seldom used in the domestic environment.


The water entry to the urinal could be from the top or from directly behind the urinal.

Most public urinals incorporate a flushing system to rinse urine from the bowl of the device to prevent foul odours. The flush can be triggered by one of several methods:

1. Manual Pushbutton or Lever

2. Voice - In some regions of Japan urinals feature a voice-activated flushing system. These flush systems are triggered by the word ‘wash!', ‘fire’ or ‘destroy the grime’ in over 30 different languages.

3. Timed flush - In the United Kingdom, Ireland, Hong Kong and some parts of Sweden and Finland, manual flush handles are unusual. Instead, the traditional system is a timed flush that operates automatically at regular intervals. Groups of up to ten or so urinals will be connected to a single overhead cistern, which contains the timing mechanism. A constant drip-feed of water slowly fills the cistern, until a tripping point is reached, the valve opens, and all the urinals in the group are flushed. Electronic controllers performing the same function are also used. This system does not require any action from its users, but it is wasteful of water where the toilets are used irregularly.

4. Automatic flush - Electronic automatic flushes solve the problems of both previous approaches, and are common in new installations. Active or (more usually) passive infrared sensors identify when the urinal has been used (or when someone has stood in front of it and moved away), and activate the flush. Door-regulated flush - This is an older method of water- saving automatic flushing, which only operates when the room is being used. A push-button switch is mounted in the doorframe of the restroom, and triggers the flush valve for all restroom urinals every time the door is opened.

Waste Drainage

As with toilets, the plumbing connection to the sewerage system must also keep smells out. A bottle trap is usually used. It is also referred to as a siphon which simply describes the siphoning action which is integral to the emptying of the bowl in any flushing system. Siphon Break , This is the point in a toilet flush when air is re-introduced into the trapway, ‘breaking’ the siphon action. The siphon break is usually heard as a deep gurgling at the conclusion of a flush. Choosing a Toilet Here is what to consider when choosing a new toilet. Here is what to consider when choosing a new toilet.

Round Front or Elongated?

• Round front toilets are more compact and can thus fit in small spaces. Elongated toilets have extra room in the front for added comfort.

One-piece, or two?

• A ‘one-piece’ toilet is actually six to ten individual pieces sculpted into a seamless unit. The result is a sleek, handcrafted toilet with no crevices between the tank and bowl to collect dirt and odours. ‘Two-piece’ toilets require a separate tank and bowl which are bolted together upon installation.

Gravity-fed or pressure-assisted flush?

• There are two basic types of toilet flushing systems; both types save water by using 6 litres of water per flush. Gravity-fed flush toilets use the force of gravity and a siphon ‘pull-through’ action to empty the bowl.

• Pressure-assisted toilets harness pressure from the water supply in the home to create a powerful ‘push-through’ flush. All waste is removed quickly in about four seconds. Pressure-assisted toilets are slightly louder and there is no condensation or ‘sweating’ on the outer tank.


• A toilet should have a deep, rich coat of glaze, ensuring an even, easy to clean glossy surface. This also applies to the internal trap way, providing a smooth surface to facilitate the flow of waste and prevent clogging.

Last Updated on Saturday, 27 November 2010 16:48

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