Water Saved by Low-Flush Toilets and Low-Flow Shower Heads

摘要

This study quantified water savings from low-flow plumbing fixtures in typical homes, collecting and analyzing data on (1) water saved by 3.5-gallon-per-flush toilets, (2) water saved by 3-gallon-per-minute shower heads, and (3) water saved by low-flow (2.75 gpm) faucets. Test sites (homes with water-saving fixtures) and control sites (homes without these fixtures) were selected nationwide; sites included singe-family and multifamily dwellings. Water use data were collected in the winter when outside-the-home irrigation was minimal and the water use differences between the two groups of homes would be easier to identify. Generally, 50-100 test homes were compared to 50-100 similar control homes in the same vicinity to determine the water savings. With the aid of occupancy data, water savings were determined on a per home per day and per capita per day basis. The study was conducted from 1981 through 1983. The study documented the water savings due to low-flush toilets, low-flow shower heads, and low-flow lavoratory faucets. The savings found were generally less than anticipated. The average measured per capita savings were 14.1 gallons per capita per day (gcd) for single-family homes and 17.5 gcd for multifamily units. The measured savings are also close to the expected savings derived from the Fixture Use Survey Report, which developed water savings estimates for individual plumbing fixtures using volunteers who monitored water use in their homes. It is recommended that the expected water savings of 13.0 gcd for single-family homes and 16.3 gcd for multifamily homes be adopted by others seeking to predict the effect of these fixtures on per capita residential water use. Tabular data are provided.