Gravity Fed (1.6 gpf, 1.28 gpf)
The most common type of toilet is a gravity-fed model which relies on the weight of the water and head pressure (height of the water in the tank) to promote the flush. If you see free-standing water when peering down into the tank, your toilet is gravity fed. Dual-flush toilets are one type of gravity-fed toilet. Dual-flush toilets let users choose from one of two flush options depending on need: Users can push one button for a regular 1.6-gpf flush, or they can push another for a reduced flush using about 0.9 gallons of water.