Water Infrastructure:

Water-Efficient Plumbing Fixtures Reduce Water Consumption and Wastewater Flows

RCED-00-232: Published: Aug 31, 2000. Publicly Released: Sep 26, 2000.

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Peter F. Guerrero
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Pursuant to a congressional request, GAO provided information on the impact of the national water efficiency standards, focusing on: (1) the estimated impact of the national water efficiency standards on water consumption levels and wastewater flows; and (2) how repealing the national standards might affect projected investments in drinking water and wastewater treatment infrastructure, state and local governments' ability to finance their infrastructure needs, and the likelihood of moratoria on new residential and commercial construction if the demand for water is unabated.

GAO noted that: (1) no studies estimating the impact of the national water efficiency standards on water consumption or wastewater flows nationwide have been completed; (2) however, studies designed to measure the impacts of using water-efficient plumbing fixtures in specific locations have shown that, compared with their less efficient counterparts, low-flow fixtures conserve water, particularly in the case of toilets; (3) a comprehensive study of water use in nearly 1,200 homes with low-flow toilets showed that the toilets used about 40 percent less water for flushing than other homes in the study; (4) estimating the impact of the national standards is difficult because some use of low-flow fixtures would likely occur for other reasons--that is, even in the absence of the standards; (5) these reasons include: (a) state and local laws that preceded the national standards; and (b) incentives, such as rebate programs sponsored by local governments, that encourage the replacement of less efficient fixtures; (6) nevertheless, major studies initiated by the American Water Works Association and the Environmental Protection Agency are developing long-term projections of the nationwide impact of the water efficiency standards, using precise measurements of the water savings per fixture as a starting point and taking into consideration expected population growth, the average replacement rate for plumbing fixtures, and other data; (7) preliminary results indicate that by 2020, water consumption could be reduced by about 3 to 9 percent, depending on the location, and wastewater flows to publicly owned treatment works could be reduced by an estimated 13 percent nationwide by 2016; (8) although, their precise impact is uncertain, repealing the national standards could affect the extent to which reductions in water consumption and wastewater flows are achieved and, thus, limit the extent to which local communities' investments in drinking water or wastewater infrastructure can be deferred or avoided; and (9) repealing the national water efficiency standards could exacerbate the financial pressures facing local communities by forcing them to build or expand treatment and storage facilities sooner than planned.

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