PFAS Testing Information

In October 2020, the Massachusetts Department of Environmental Protection (MassDEP) established new drinking water regulations that set a maximum contaminant level of 20 ppt for the family of chemicals known as PFAS. Public water suppliers serving populations between 10,000 and 50,000 (such as Medfield) were required to begin initial testing in April 2021. Testing levels below 20 ppt are deemed safe.

In January 2021, the Town conducted voluntary testing ahead of the deadline for the Town to begin testing. The results are shown on the table below. Based on these results, Medfield will continue to test for PFAS on a monthly basis, beginning in April 2021, at locations with results over 10 ppt, if the wells are in use at that time. Locations with results less than 10 ppt will be tested on a quarterly basis, beginning in April 2021. At this time, no additional action is required.


January (Initial)

February (Confirmatory)


Well 1 (Route 109)

Part of Main Street Blend

14 ppt

Part of Main Street Blend

Well 2 (Route 109)

Part of Main Street Blend

13 ppt

Part of Main Street Blend

Main Street Blend (Wells 1 and 2)

18 ppt

13 ppt

16.4 ppt

Well 3 (off Elm Street)

15 ppt

12 ppt

Well not operational in April

Well 4 (off Elm Street)

2 ppt 


Well not operational in April

Well 6 (Route 27)

4.3 ppt



6 compounds tested: PFOS, PFOA, PFHxS, PFNA, PFHpA, PFDA

Maximum contaminant level: 20 parts per trillion

Given the Town’s commitment to keeping residents informed, we are providing this information although the PFAS test results do not trigger a formal notice to the community under drinking water regulations. We will continue to provide updates on testing results. 

PFAS are a family of man-made chemicals that have been used since the 1950s in a number of products including nonstick cookware, water resistant clothing, food packaging materials, and firefighting foam. Please visit MassDEP’s website for additional information about PFAS. 

The Town is committed to managing and protecting our water supply. The Board of Water and Sewerage and Department of Public Works remains engaged with MassDEP, the Massachusetts Water Works Association, neighboring towns, and other stakeholders to ensure compliance with regulations and awareness of new developments regarding PFAS and the public water supply. If you have any questions or concerns, please contact the Water Division at 508-906-3004 or email DPW Director Maurice Goulet at