How Often Should Residential Septucs Be Cleaned Out

Near ane-fifth of U.S. households are not connected to a public sewer.

More than 21 million households in the United states apply septic systems — not a public sewer — to trap and filter their toilet waste product.

The underground tanks are most mutual in rural areas, peculiarly in New England and the Deep South. They are an frequently overlooked source of water pollution and disease transmission.

In the graphic below, the peak map shows the portion of homes in each state that use septic systems. Darker colors indicate a college percentage. Vermont tops the chart, with 55 percent of homes on septic. The data is from 1990, which is the most recent state-level septic system assessment. The U.S. Census Bureau, which collected the information, stopped doing and then for states and counties after 1990 because no federal agency regulates septic systems. A national approximate, from a much smaller sample size, is completed every two years as role of the American Housing Survey.

Many homes are still being built with septic systems. The lesser map shows the portion of homes built in 2013 that came with septic systems. The trend follows historic geographical patterns: more than half of new homes in New England did not connect to a public sewer.

Graphic © Kaye LaFond / Circle of Blueish

The share of households that use septic systems varies by land. The highest concentrations are in New England, where 55 pct of Vermonters use septic, and the Southeast. The aforementioned regions have the highest share of new homes congenital with septic systems. Click image to enlarge.

This graphic was fabricated to accompany the article America'due south Spreading Septic Threat past Circle of Bluish reporter Brett Walton. Contact Brett Walton or past @waltonwater on Twitter.

is both a scientist and a journalist, she holds an MS in Environmental Engineering from Michigan Technological University, and she brings proficiency in ESRI's ArcGIS mapping software.