Water Smart Indoors

Get to Know Your Toilet

How a standard gravity flush toilet operates
Different types of toilets

A toilet's main purpose is to fill the bowl with enough water to flush waste down the drain and then refill the bowl with fresh water. Toilets have two main parts: the tank and the bowl.

diagram of a toilet

How a Standard Gravity Flush Toilet Operates

The handle is connected to a chain on the inside of the tank
When the handle is pushed down, it pulls the chain which is connected to the flush valve and causes it to lift
As the chain lifts the flush valve (which then floats out of the way), it exposes the drain hole
Uncovering this hole allows water to escape the tank and enter the toilet bowl
The water then pushes the contents of the toilet bowl past the trap and into the main drain, or drainpipe
As the tank empties, the float ball that has been floating at the top of the tank drops down, which activates the ball cock or water valve
The water valve opens a water-supply valve that refills the tank
As the tank refills with water, the float ball floats back up
Once the water level reaches the right height in the tank, it shuts off the valve
A bend in the pipe just below the toilet serves as a water-filled trap that blocks the rise of sewer gases
Waste then drains into a municipal sewer or to a septic tank

Different Types of Toilets

Type	Description	Pros	Cons
Gravity Flush	Requires gravity to operate	Common Inexpensive Eliminates need for a larger volume of water	Flapper valve may leak or breakdown
Vaccum Assist	Relies on gravity and a strong siphoning action created by a special bowl and tank design	Requires fewer cleanings as a greater area of the bowl is covered with water Larger trap minimizes the chance of blockage	Flapper valve may leak or breakdown
Dual Flush	Users can choose to flush with 3L (half flush) or 6L (full flush)	Largest trap size of any 4 inch bowl No flapper valve means no flapper repairs or leaking	Expensive Limited Selection
Pressure Assist	Uses pressure instead of gravity to create a forceful flush	Larger water surface area requires fewer cleanings No flapper valve means no flapper repairs or leaking	Expensive Limited Selection
Tip Bucket	Uses a bucket located in the top of the tank. When flushed, the lever causes the bucket to tip over, emptying its water into the toilet bowl	Tamper proof Water does not touch the porcelain of the tank, eliminating sweating No flapper valve means no flapper repairs or leaking	Limited Selection

Back to the Bathroom

Revised: Monday April 20 2009

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