According to the EPA’s WaterSense, toilets are the main source of water consumption in the home, accounting for nearly 30 percent of a home’s indoor water use and homes with older toilets use even more water. We recommend retrofitting your bathroom with a low-flow, WaterSense labeled toilet and save nearly 11 gallons per toilet per day.
There are two basic types of water-efficient low-flow toilets; the first is a low toilet that never exceeds the 1.28 gallons per flush each time.
The second is toilet type is called a dual flush toilet because they have two levers or buttons on the toilet which allows for different amounts of water to be used depending on what you are flushing. The toilets have one lever or button to do a “half flush” or typically 0.8 gallons (depending on manufacturer) when flushing liquid waste. The other lever or button allows for a “full flush” or typically 1.6 gallons (depending on manufacturer) when flushing solid waste.