Septic Systems Fact Sheet Office of Wastewater Management i Decentralized Wastewater Program This fact sheet presents data on soil-based septic systems collected by the U.S. Census Bureau for the 2007 American Housing Survey, based on a sampling of 55,000 housing units. Septic System Use • In 2007, an estimated 20 percent (26.1 million) of total U.S. housing units were served by septic systems. This is an increase of 1.54 million septic systems since 1985. • In 2007, 22 percent (1.6 million) of all housing units less than 4 years old used septic sys- tems. Demographics Total housing units served by septic and centralized/ clustered systems septic systems (20%) Total housing units served by septic systems 1985 1989 2001 2007 24.6 25.1 125.8 I 26.1 22 23 24 25 26 27 total housing units (millions) • In 2007, 50 percent (13.1 million) of total housing units with septic systems in the United States were in rural areas, 47 percent (12.3 million) were in suburbs, while 3 percent (774,000) were found in central cities. • In 2007, 46 percent (10.1 million) of occupied housing units with septic systems were located in the southern region of the United States, followed by the midwest with 22 percent (4.8 million), the northeast region with 19 percent (4.2 million), and the west with 13 percent (2.9 million). Total housing units served by septic systems, by rural/ urban/suburban classification central cities 3%) Occupied housing units served by septic systems, by U.S. Region*** *Total housing units served by a soil-based septic system for 5 or fewer units. **Total housing units connected to a city, county, sanitary district, neighborhood, or subdivision sewer system serving 6 or more units (includes centralized and clustered onsite systems). ***Based on occupied housing units served by a soil-based septic systems (total housing units not available by region). Source: U. S. Census Bureau - American Housing Surveys for the United States, 1985 through 2007, Tables 1A-4, 1B- 4, 1C-4, 1D-4, and 2.4. The American Housing Survey is conducted by the U.S. Census Bureau, Housing and Household Economic Statistics Divi- sion every two years to determine up-to-date housing statistics. Field data cover an average of 55,000 housing units. A sample of housing units in all survey areas was selected from the decennial census. The survey goes back to the same housing units on a regular basis, recording changes in characteristics, adding and deleting units when applicable. This cross-sectioning of the housing inventory gives a picture of houses and households as they change over long periods of time. Since these estimates are based on samples, they may differ from the results that would have been obtained if a complete census had been taken under the same interviewing conditions. Web site - www.census.aov/hhes/www/housina/ahs/ahs.html US EPA Decentralized Wastewater Program - For more information visit www.epa.gov/owm/onsite EPA# 832-F-08-057 Oct. 2008 ------- |