Federal law mandates that all new toilets use no more than 1.6 gallons per flush, compared to old models that used 3.5 gallons or more.
Gravity-fed toilets operate with a conventional flush, where water draining from the tank is released into the bowl and its weight and gravity pull waste down the drain.
Pressure-assisted units use pressure built up within the water supply to increase the force of the flush. These tend to be noisier than gravity-fed models, but the bowl empties quickly (within 4 seconds). The larger water seal surface results in fewer stains. Since the trapway on pressure-assisted models has fewer bends, it is less likely to clog than a gravity-fed system.
A third type of toilet uses a pump to assist the flushing operation with increased pressure. Some models are even designed to flush automatically when the seat lid is closed. Dual flushers feature a lever that uses 1.6 gallons for solid waste removal and 1.1 gallons for liquid waste.
The rough-in is the distance from the finished wall to the center of the sewer outlet. Standard rough-ins are 10″, 12″ or 14″.
DIY Frequently Asked Questions / Standard Toilet')">
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