A low flush or low flow toilet is a flush toilet that uses significantly less water than a full flush toilet. Most low flush toilets use 6 liters, or 1.6 gallons per flush as opposed to the usual 13.2 liters, or about 3.5 gallons. They came into use in the United States in the 1990s, citing water conservation concerns.[1] Many dual flush toilets have a 6 litre and a lower flush.
In 1992 President George H. W. Bush signed the Energy Policy Act. This law made 1.6 gallons per flush toilets standard. This law went into effect in Jan 1, 1994 for residential buildings and Jan 1, 1997 for commercial building where it can't consume more than 1.6 gallons per flush. Many people disliked the low flow toilets because they had to flush the toilets twice to achieve their desired task. Joe Knollenberg, a Congressman from Michigan tried to repeal the law but was unsuccessful. The performance of some low flow toilets has significantly improved since 1994. Research has shown that low flow toilets can save a family of 4 more than 22,000 gallons of water yearly.[2]
In 2011, the San Francisco Chronicle reported that, while low-flow toilets are estimated to have saved the city of San Francisco 20 million gallons of water per year, the reduction in water volume has caused waste sludge to back up in the city sewer pipes. The city is attempting to solve this by adding chlorine bleach to the pipes, a proposal that has raised environmental objections.[3]