According to NAHB Economics analysis of the Survey of Construction (SOC) data, almost 9% of new single-family homes started in 2021 are served by individual wells and 16% have private septic systems. These shares, however, vary widely across the nine Census divisions with the corresponding shares reaching 36% and 44% 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, nearly 9% of new single-family homes started in 2021 are served by individual wells, while 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 four times as large as the national median, 36% 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 23% of new single-family homes started in 2021 are built with individual wells. The South Atlantic division registers the third highest share of homes built with individual wells with the share of 12%. These three divisions exceed the national average of 9%.
In contrast, individual wells are almost non-existent in the East South Central and West South Central divisions where their shares are 1% and 3%, 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. Almost 84% of new single-family homes started in 2021 are serviced by public sewers. The share of new home built with individual septic systems increased slightly from 15% in 2020 to 16% in 2021. The incidence of individual septic systems among new single-family starts varies by division.
In New England, about 44% of new single-family homes started in 2021 have private septic systems. Individual septic systems are also relatively common in the East South Central division and the East North Central division, where 35% and 24% of homes started in 2021 have a private septic system, respectively. The share of individual septic systems in the South Atlantic division is 19%, above the national average of 16%. The shares of individual septic systems are below the national average in the West North Central (13%), Middle Atlantic (11%), West South Central (10%), Mountain (9%), and Pacific (8%) divisions.
Compared to the previous year, the share of new single-family homes built in 2021 with individual septic systems increased in six divisions, while the share decreased in the Pacific, East north Central and Middle Atlantic division. It is noticeable that in the Middle Atlantic division the share of individual septic systems decreased from 18% in 2020 to 11% in 2021.