Private Well Owners: Important Information, please read below. Residents on Public Water Supply: This information does not apply to you.


Below are state-wide overview maps, as well as a listing of all of the towns that were either completely or partially located within the study area included in the USGS Study Report. The full title of the report is: "Scientific Investigations Report 2011-5013, Arsenic and Uranium in Water from Private Wells Completed in Bedrock of East-Central Massachusetts: Concentrations, Correlations with Bedrock Units, and Estimated Probability Maps."

State-wide Maps for Arsenic & Uranium Probability

Probability of Exceeding the Arsenic Drinking Water Standard in Private Drinking Water Wells in Massachusetts - Map pdf format of    Map of Possible Arsenic in Drinking Water Wells

Probability of Exceeding the Uranium Drinking Water Standard in Private Drinking Water Wells in Massachusetts - Map pdf format of    Map of Possible Uranium in Drinking Water Wells  file size 1MB

Detailed Town Maps

The town listing includes towns that were outside the study area but include bedrock units that were in the study area and for which probability information is available. The listing also includes towns that are mapped as areas of granite or pegmatite bedrock units that were not included in the USGS study area, but may have an increased probability for containing radionuclide contaminants such as radon, radium and uranium.

Please note that not all of the towns included in the list have increased probabilities of having arsenic and radionuclide contamination in private bedrock aquifer wells. Those towns with an asterisk in the listing were not identified with bedrock units having an increased probability of containing water with naturally occurring arsenic or uranium levels exceeding public drinking water standards. Furthermore, there are many towns on this list that are either mostly or entirely served by public water supplies rather than private bedrock wells.

To review the town maps, open the PDF file below and click on the links next to your town to obtain a PDF map of the arsenic or uranium probability zones for your town. If you chose to open the Word version of the listing, then  use CTRL click to open the map. If your town is not included the list, then there is no arsenic and uranium probability information available for your town. Please note that for many of these towns there are some areas for which arsenic or uranium probability information is not available.

Note: Information in these maps only applies to bedrock aquifers. If your well is located in a sand or sand and gravel aquifer, this information does not apply. Most, if not all, drinking water wells installed in the Plymouth-Carver Aquifer and on Cape Cod, Martha's Vineyard, and Nantucket are completed in sand or sand and gravel deposits rather than bedrock. Therefore, these maps do not apply to those areas.