NAHB Economics analysis of the Survey of Construction (SOC) data shows that less than 9% of new single-family homes started in 2016 are served by individual wells and close to 16% have private septic systems. These shares, however, vary widely across the nine Census divisions with the corresponding shares reaching 37% and 43% in New England – the highest occurrence rates in the nation.
The SOC classifies sewage disposal systems as public sewers (including community or shared sewage/septic systems) and individual septic systems. Most of new single-family homes (84%) are serviced by public sewers. The incidence of individual septic systems among new single-family starts varies by region.
Close to a half of new single-family homes started in New England have private septic systems, while the national share is 16%. Individual septic systems are also relatively common in the East South Central division and East North Central division where 27% of homes started in 2016 have a private septic system. The share of private septic systems is close but slightly higher than the national average in the South Atlantic division (16.6%) and the Middle Atlantic division where it exceeds 17%.
The common sources of water supply also differ noticeably by geographic location. Similarly to sewage/septic systems, the SOC classifies community or shared water supply/wells as public rather than individual wells. Nationally, close to 9% of new single-family homes started in 2016 are served by individual wells, and the remaining vast majority of new homes are served by a public water system, including shared water wells.
In New England, where new homes sit on nation’s largest lots and are more likely to be custom-built, 37% of new single-family homes are built on individual wells. The reliance on private wells is also relatively common in the East North Central where one in four new single-family homes started in 2016 are built on individual wells. The Middle Atlantic divisions registered the third highest share of homes built on individual wells, 14% – exceeding the national average of 8.9%.
In contrast, individual wells that are not shared are almost non-existent in the East South Central and West South Central divisions where their shares are under 1% and 3%, respectively.