NAHB Economics analysis of the Survey of Construction (SOC) data shows that about 9% of new single-family homes started in 2019 were served by individual wells and almost 17% have private septic systems. These shares, however, vary widely across the nine Census divisions with the corresponding shares reaching 37% and 45% 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 2019 are served by individual wells, and most of new homes are served by public water systems, including community or shared water supply/wells.
In New England, where median lot size is three times as large as the national median, 37% of new single-family homes are built with individual wells. The reliance on private wells is also relatively common in the East North Central division where 25% of new single-family homes started in 2019 are built with individual wells. The Middle Atlantic division registers the third highest share of homes built with individual wells with the share of 16%. 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 are almost non-existent in the East South Central and West South Central divisions where their shares are under 1% and 2%, respectively.
Like public water/individual wells, sewage disposal systems were classified by public sewers (including community or shared sewage/septic systems) and individual septic systems. Most of new single-family homes (83%) are serviced by public sewers. Compared to new home started in 2018, the share of new home built with individual septic systems in 2019 increased from 15.7% to 16.7%. The incidence of individual septic systems among new single-family starts varies by division.
In New England, about 45% of new single-family homes started in 2019 have private septic systems. Individual septic systems are also relatively common in the East South Central division and the East North Central division, where 37% and 26% of homes started in 2019 have a private septic system, respectively. The shares of individual septic systems in the Middle Atlantic division (17%) and the South Atlantic division where it is 19% are close to the national average. The shares of individual septic systems are below the national average in the West North Central (13%), Pacific (11%), Mountain (10%) and West South Central (9%) divisions.
Compared to the previous year, the share of new single-family homes built in 2019 with individual septic systems increased in eight divisions, while the share decreased slightly in the Middle Atlantic division.—