Low-Flow and Dual-Flush Toilets
High-efficiency, low-flow toilets often have a dual-flush system.
Since 1994, building code has made low-flow toilets mandatory when installing a new toilet. These toilets use a maximum of 1.6 gallons of water per flush (gpf’s), compared to the 3.5 (or more) gallons of old. Today’s models are even more effective than the original low-flow toilets. In fact, high-efficiency toilets (HETs) use a lower gpf in general, while dual-flush toilets offer a "low and lower" gpf as an option.
A lever handle on a dual-flush toilet.
Dual-flush toilets have two separate flush settings: one for liquid waste, and one for solid waste. Often dual flush toilets have separate buttons, cleverly labeled “1” and “2,” to initiate each type of flush. The liquid-waste setting uses less water per flush than the solid-waste setting, thus making dual-flush toilets more eco-friendly than standard toilets.