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Low Flow Plumbing Fixtures

Save substantial amounts of water compared to conventional fixtures

Photo of a low-flow showerhead.

It's not just low flow, it's the law. In 1995, the National Energy Policy Act mandated the use of toilets that use no more than 1.6 gallons of water per flush. Since then, low-flow plumbing fixtures including toilets, faucet aerators and showerheads have been developed that save substantial amounts of water compared to conventional fixtures while providing the same utility.

Different types of low-flow toilets use various technologies aimed at making the toilet more functional. Some toilets have large drain passages, redesigned bowls and tanks for easier wash down. Others supplement the gravity system with water supply line pressure, compressed air, or a vacuum pump.

Conventional faucet aerators don't compensate for changes in inlet pressure, so the greater the water pressure, the more water you use. New technology compensates for pressure and provides the same flow regardless of pressure. Aerators are also available that allow water to be turned off at the aerator itself. Showerheads use similar aerator technology and multiple flow settings to save water.

Low-flow toilets use a maximum of 1.6 gallons of water per flush compared with about 3.5 gallons of water used by a standard toilet. Low-flow shower heads use about 2½ gallons of water per minute compared to between four and five gallons per minute used by conventional heads. Low-flow faucet aerators can cut the water usage of faucets by as much as 40% from 4 gallons per minute to 2½.

More about Low Flow Fixtures is available in this online video.

Environmental Performance

Low flow fixtures save water that would otherwise be wasted, not only reducing your utility bill, but also the amount of available fresh water used.


Most low flow fixtures can be installed by the homeowner by hand. However, toilets are more complicated and will require certain tools and understanding. In some cases, a plumber should be consulted or utilized for installlation.

Low flow fixtures can be found in many hardware stores. Many toilets on the market today are low flow toilets.

Costs of low flow fixtures are similar to conventional fixtures, and the faucets and showerheads may be slightly more expensive.

Not Applicable

Low flow plumbing fixtures must meet the appropriate American National Standards Institute (ANSI) standards listed by the International Association of Plumbing and Mechanical Officials (IAPMO).

MADE Project: Bowie, Maryland

Installation of low-flow plumbing fixtures is similar to that of conventional fixtures. The majority of these fixtures require no special connections or fittings.

Typically a limited warranty from 1 to 5 years depending on type of fixture and manufacturer.

Easy installation procedures make low flow plumbing fixtures feasible for retrofitting. It is estimated that low-flow toilets alone could save up to 22,000 gallons of water per year for a family of four. Low-flow plumbing fixtures are available in all the styles and colors of conventional fixtures. Low-flow faucet aerators and showerheads are available at little additional cost.

The initial introduction of low flow toilets generated complaints that the low-flow toilets had trouble clearing the bowl and frequently clog. Flushing performance has improved in recent years but some models may still not perform as well as older high flow toilets.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.