A low-flush toilet (or low-flow toilet or high-efficiency toilet) is a
flush toilet
A flush toilet (also known as a flushing toilet, water closet (WC) – see also toilet names) is a toilet that disposes of human waste (principally urine and feces) by using the force of water to ''flush'' it through a drainpipe to another lo ...
that uses significantly less water than traditional high-flow toilets. Before the early 1990s in the United States, standard flush toilets typically required at least 3.5 gallons (13.2 litres) per flush and they used float valves that often leaked, increasing their total water use. In the early 1990s, because of concerns about water shortages, and because of improvements in toilet technology, some states and then the federal government began to develop water-efficiency standards for appliances, including toilets, mandating that new toilets use less water. The first standards required low-flow toilets of 1.6 gallons (6.0 litres) per flush. Further improvements in the technology to overcome concerns about the initial poor performance of early models have further cut the water use of toilets and while federal standards stagnate at 1.6 gallons per flush, certain states' standards toughened up to require that new toilets use no more than 1.28 gallons (4.8 litres) per flush, while working far better than older models.
Low-flush toilets include single-flush models and
dual-flush toilets, which typically use 1.6 US gallons per flush for the full flush and 1.28 US gallons or less for a reduced flush.
Water savings
The
US Environmental Protection Agency
The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it be ...
's ''
WaterSense
WaterSense is a program sponsored by the U.S. Environmental Protection Agency (EPA), designed to encourage water efficiency in the United States through the use of a special label on consumer products.U.S. Environmental Protection Agency (EPA), Was ...
'' program provides certification that toilets meet the goal of using less than 1.6 US gallons per flush. Units that meet or exceed this standard can carry the WaterSense sticker. The EPA estimates that the average US home will save
US$
The United States dollar (symbol: $; code: USD; also abbreviated US$ or U.S. Dollar, to distinguish it from other dollar-denominated currencies; referred to as the dollar, U.S. dollar, American dollar, or colloquially buck) is the official ...
90 per year, and $2,000 over the lifetime of the toilets.
Dry toilet
A dry toilet (or non-flush toilet, no flush toilet or toilet without a flush) is a toilet which, unlike a flush toilet, does not use flush water. Dry toilets do not use water to move excreta along or block odors. They do not produce sewage, and ar ...
s can lead to even more water savings in private homes as they use no water for flushing.
Problems
The early low-flush toilets in the US often had a poor design that required more than one flush to rid the bowl of solid waste, resulting in limited water savings. In response, US Congressman
Joe Knollenberg
Joseph Kastl Knollenberg (November 28, 1933 – February 6, 2018) was an American politician from Michigan. From 1993 to 2009, he was a Republican member of the U.S. House of Representatives, representing and .
In his congressional term, Knol ...
from Michigan tried to get Congress to repeal the law but was unsuccessful, and the industry worked to redesign and improve toilet functioning. Some reduction in sewer flows have caused slight backups or required redesign of wastewater pipes, but overall, very substantial residential water savings have resulted from the change over time to more efficient toilets.
History
In 1988 Massachusetts became the first state in the US to mandate the use of low-flush toilets in new construction and remodeling. In 1992 US President
George H. W. Bush
George Herbert Walker BushSince around 2000, he has been usually called George H. W. Bush, Bush Senior, Bush 41 or Bush the Elder to distinguish him from his eldest son, George W. Bush, who served as the 43rd president from 2001 to 2009; pr ...
signed the
Energy Policy Act. This law made 1.6 gallons per flush a mandatory federal maximum for new toilets. This law went into effect on January 1, 1994 for residential buildings and January 1, 1997 for commercial buildings.
The first generation of low-flush toilets were simple modifications of traditional toilets. A valve would open and the water would passively flow into the bowl. The resulting water pressure was often inadequate to carry away waste. Improvements in design now make modern models not only more water-efficient but more effective than old models. In addition to tank-type toilets that "pull" waste down, there are also now pressure-assist models, which use water pressure to effectively "push" waste.
See also
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Low-flow fixtures A low-flow fixture is a water saving plumbing fixture designed to achieve water savings by having a lower flow rate of water or a smaller quantity per flush. Some of these low-flow fixtures are faucets, showerheads, and toilets. In the United States ...
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Dual flush toilet
A dual flush toilet is a variation of the flush toilet that uses two buttons or a handle mechanism to flush different amounts of water.
The purpose of this mechanism is to reduce the volume of water used to flush different types of waste. The de ...
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Sewer dosing unit
A sewer dosing unit (SDU) is a plumbing device to allow effective sewage disposal with low liquid-flow rates. With a global emphasis on water saving, many new buildings and renovations are seeing the installation of water saving fixtures such as lo ...
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Waterless urinal
A urinal (, ) is a sanitary plumbing fixture for urination only. Urinals are often provided in public toilets for male users in Western countries (less so in Muslim countries). They are usually used in a standing position. Urinals can be wit ...
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Residential water use in the US and Canada
A residential area is a land used in which housing predominates, as opposed to industrial and commercial areas.
Housing may vary significantly between, and through, residential areas. These include single-family housing, multi-family resid ...
References
{{Authority control
Toilets
Toilet types
Water conservation
Water conservation tools
Sustainable products
Bathrooms