BasementSoil

Massachusetts: basement moisture and foundation risk by county

14 counties, ranked by our combined index. Highest combined risk is Nantucket County (41), lowest is Berkshire County (31). The worst soil for foundation cracks specifically is in Nantucket County.

Where in Massachusetts the ground is worse

Every county in the state, coloured by the soil values below. Click a county to open its report; switch what the colour means with the buttons. The pattern is geology, not administration — risk stops at the edge of a physiographic region, not at a county line.

Barnstable County, MA — combined 35/100, moisture 41, movement 20, water table 46Berkshire County, MA — combined 31/100, moisture 41, movement 18, water table 30Bristol County, MA — combined 31/100, moisture 39, movement 19, water table 30Dukes County, MA — combined 34/100, moisture 42, movement 15, water table 46Essex County, MA — combined 38/100, moisture 40, movement 14, water table 66Franklin County, MA — combined 38/100, moisture 44, movement 25, water table 46Hampden County, MA — combined 34/100, moisture 39, movement 31, water table 30Hampshire County, MA — combined 34/100, moisture 39, movement 29, water table 30Middlesex County, MA — combined 35/100, moisture 43, movement 15, water table 46Nantucket County, MA — combined 41/100, moisture 42, movement 35, water table 46Norfolk County, MA — combined 41/100, moisture 39, movement 25, water table 66Plymouth County, MA — combined 34/100, moisture 41, movement 16, water table 46Suffolk County, MA — combined 39/100, moisture 41, movement 16, water table 66Worcester County, MA — combined 35/100, moisture 41, movement 18, water table 46
  • Low (0–27)
  • Moderate (28–49)
  • Elevated (50–74)
  • High (75–100)

County boundaries: US Census TIGER (public domain), simplified for display. Colours are our index from USDA SSURGO fields where loaded, otherwise from our regional model — each county page states which. How the index is calculated.

CountyIndexMoistureCracksWater tableRegion
Nantucket County41423546Atlantic coastal plain
Norfolk County41392566Glaciated New England upland
Suffolk County39411666Glaciated New England upland
Essex County38401466Glaciated New England upland
Franklin County38442546Glaciated New England upland
Barnstable County35412046Atlantic coastal plain
Middlesex County35431546Glaciated New England upland
Worcester County35411846Glaciated New England upland
Dukes County34421546Atlantic coastal plain
Hampden County34393130Glaciated New England upland
Hampshire County34392930Glaciated New England upland
Plymouth County34411646Atlantic coastal plain
Berkshire County31411830Glaciated New England upland
Bristol County31391930Glaciated New England upland

Values from USDA NRCS SSURGO where available, otherwise our regional model — each county page states which. Methodology.

The physiographic regions inside Massachusetts

State lines are political; soil follows geology. These are the distinct ground types inside Massachusetts and why each behaves the way it does.

Glaciated New England upland

A hardpan under thin till creates a perched water table — water stands above an impermeable layer even though the regional water table is deep. It is the commonest cause of a wet basement in New England. Expansive clay is largely absent.

10 counties: Berkshire County, Bristol County, Essex County, Franklin County, Hampden County, Hampshire County, Middlesex County, Norfolk County, Suffolk County, Worcester County

Atlantic coastal plain

Extremely variable over short distances: sand and saturated clay side by side. A county figure means less here than anywhere else we cover — the individual parcel decides.

4 counties: Barnstable County, Dukes County, Nantucket County, Plymouth County

Page data updated