In 1994, the National Energy Policy Act was signed into law. It requires that toilets sold in the United States use no more than 1.6 gallons (6 liters) per flush [source: Green Living]. This mandate to conserve has given rise to a new generation of high efficiency toilets (HETs) that use technologies like pressure-assist, gravity flush and dual flush to whisk away waste using as little water as possible. Of the new technologies, the dual flush method has the advantage of intuitive flushing, where the operator can decide electively that less water is needed and use one gallon (3 liters) or less per flush instead of the 1.6 gallon maximum.
Although toilets purchased for new construction and retrofits must meet the new standards, millions of older water-guzzling toilets are still out there. As water and sewer costs keep rising, low flow toilets are becoming more attractive to the American consumer, and local and state governments are using rebates and tax incentives to encourage households to convert to these new technologies.
The advantages of low flow toilets in conserving water and reducing the demand on local water treatment facilities is pretty obvious. According to USA Today, the average person flushes the toilet five to eight times a day, and at a greedy five gallons a flush, the numbers start to add up quickly [source: Winter]. According to the Environmental Protection Agency, completely eliminating old style, water guzzling toilets would save about 2 billion gallons of water each day in the United States [source: Green Living]. With a growing population, an aging water treatment infrastructure and the looming threat of global warming contributing to uncertain weather, water conservation will continue to be a big issue.
How does the dual flush toilet fit into this picture? No one knows for sure. Most major toilet manufacturers are gearing up to provide these water saving toilets, but whether or not the American public will embrace a change in the way they approach their bathroom habits remains to be seen.