Tested Water

Arsenic in Massachusetts well water, by county

Arsenic is widespread, over the limit in 15% or more of tested wells, in 1 of the 5 Massachusetts counties with 10 or more tested wells. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.

How Massachusetts compares with the rest of the country

Across Massachusetts, about 1 in 15 tested wells had arsenic over the EPA limit of 10 µg/L (14 of 215). Across all tested wells in the US it's about 1 in 9. That's less often than in the country as a whole. Counties still differ, so check yours below.

Why it matters: Drinking it for years raises the risk of skin, bladder and lung cancer.

Arsenic dissolves out of certain rocks and old sediments, so it can be high even where nobody has polluted anything.

Arsenic in tested wells, county by county

Share of each county's tested wells with at least one result over the EPA limit of 10 µg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.

CountyWells testedWells over the limitLevel
Worcester County 64
16% 10 of 64
Widespread
Middlesex County 12
8% 1 of 12
Worth checking
Barnstable County 77
3% 2 of 77
Rare
Plymouth County 19
0% 0 of 19
Rare
Hampden County 11
0% 0 of 11
Rare

6 more Massachusetts counties have 1 to 9 tested wells for arsenic, too few to rate.

Download this table (CSV) · Free to reuse under CC BY 4.0

Where to get your well tested for arsenic in Massachusetts

1

Your county health department

Massachusetts doesn't run a statewide free testing program that we know of. Some county health departments test wells or sell kits, so call yours first.

Massachusetts's private well page
3

A mail-in kit

Fill the bottles at your kitchen tap and mail them back. We mark the kits that include arsenic.

Compare kits

Keep reading about wells in Massachusetts

Questions people ask about arsenic in Massachusetts

Is there arsenic in Massachusetts well water?

Arsenic is widespread, over the limit in 15% or more of tested wells, in 1 of the 5 Massachusetts counties with 10 or more tested wells. Across Massachusetts, about 1 in 15 tested wells had arsenic over the EPA limit of 10 µg/L (14 of 215). Across all tested wells in the US it's about 1 in 9. That's less often than in the country as a whole. Counties still differ, so check yours below.

Where can I get my well tested for arsenic in Massachusetts?

Use a lab certified by Massachusetts for drinking water, or a mail-in kit that includes arsenic from a certified lab. Some county health departments test wells too, so call yours first.

See Massachusetts's list of certified labs, or compare mail-in kits.

Where these numbers come from

  • Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA limit of 10 µg/L. Wells tested for studies and monitoring, not a random sample of homes.
  • Likely overstated: our own check of who tested the wells, when and where. How we check.
  • State programs and links: Massachusetts Department of Environmental Protection (MassDEP).