NAHB Economics analysis of the Survey of Construction (SOC) data shows that about 9% of new single-family homes started in 2017 were served by individual wells and more than 16% have private septic systems. These shares, however, vary widely across the nine Census divisions with the corresponding shares reaching 39% and 43% in New England – the highest occurrence rates in the nation.
The SOC classifies community or shared water supply/wells as public water rather than individual wells. Nationally, more than 9% of new single-family homes started in 2017 are served by individual wells, and the remaining vast majority of new homes are served by a public water system, including community or shared water supply/wells.
In New England, where new homes sit on nation’s largest lots, 39% of new single-family homes are built on individual wells. The reliance on private wells is also relatively common in the East North Central division where 27% of new single-family homes started in 2017 are built on individual wells. The Middle Atlantic division registers the third highest share of homes built on individual wells with the share of 15%. Four out of the nine divisions exceed the national average of 9%, including New England, East North Central, Middle Atlantic and South Atlantic.
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 2%, respectively.
Similar to public water/individual wells, 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 division.
About 43% 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 the East North Central division where 28% of homes started in 2017 have a private septic system. The share of private septic systems is close but slightly higher than the national average in the Middle Atlantic division (20%) and the South Atlantic division where it is 17%.