PFAS - Wilmington FAQ

Are other public water sytems dealing with this?

Yes, communities across the state and throughout the country have detected PFAS in their public water supplies at varying levels of concentration. As of this week, approximately 75 public water systems in Massachusetts alone have detected PFAS above the MADEP Maximum Contaminant Level (MCL). 

What are PFAS?

PFAS are a family of manmade chemicals used for non-stick coatings and firefighting foams.  Certain PFAS were discontinued in the U.S. about 30 years ago, but they may still be used in imported products.  PFAS are resilient and do not degrade easily in soil and water.  As a result, they are widely found in the environment where they migrate to the food supply and drinking water.

The PFAS6 Regulated Under MassDEP’s Drinking Water Standard


perfluorooctanoic acid


perfluorooctane sulfonic acid


perfluorohexane sulfonic acid


perfluorononanoic acid


perfluoroheptanoic acid


perfluorodecanoic acid

Is PFAS in our local public drinking water?

After following a series of testing protocols in conjunction with the Massachusetts Department of Environmental Protection and awaiting laboratory test results, we have learned of the presence PFAS chemical compounds (PFAS6) at levels above the state standard of 20 parts per trillion in the following water source(s):

10/6/21: Sargent Water Treatment Plant: 20.6 parts per trillion

**Please note that a follow up sample was taken on 10/21/21 that showed that the level of PFAS was back down to 16.5 parts per trillion, below the state standard of 20 parts per trillion. 

What does part per trillion mean?

Standards for PFAS levels in drinking water are customarily given in units of ng/L (nanograms/Liter) which is equivalent to parts per trillion or ppt. To realize how small a value this actually is and how difficult this contaminant is to trace in the environment, read the analogies listed below:

One part per million (ppm) equals:

1 inch in 16 miles

One part per billion (ppb) equals:

1 inch in 16,000 miles

One part per trillion (ppt) equals:

1 inch in 16 million miles (600+ times around the earth)

Another way to think about it is, one (1) ppt would be represented by a single drop of water in 18 million gallons of water. That is one drop of water in roughly 20 Olympic sized swimming pools.

Why wasn't this an issue until now?

Relatively recent advances in laboratory  testing now enables us to test for PFAS compounds at extremely low levels. Water systems like Wilmington, who previously tested negative for certain PFAS at parts per billion may now test positive at parts per trillion. The Massachusetts DEP lowered the standard of PFAS6 levels to 20 ng/l (equals 20 parts per trillion) in October of 2020 with Wilmington required to test at that level for the first time in April 2021.

What is the Town doing to address the situation?

While the sample result does not constitute a drinking water violation, the Town has constructed a plan of action to reduce the amount of PFAS in the drinking water and has taken the following actions since receiving the sample result: Click HERE for our actions.

What should I do as a resident?

Unless you are in a sensitive subgroup, there is no recommendation by MassDEP to stop drinking and using the water. The 20PPT value is applicable to a lifetime of consuming the water. If you are concerned still, you can purchase a home water treatment system or bottled water. Be aware that not all bottled water is PFAS6 free. Please visit for the full list. Please note that a sample taken on 10/21/21 showed that levels of PFAS are back below 20 PPT. 

What can I do if I am in a sensitive subgroup?

Those in a sensitive subgroup are advised by the MA Department of Environmental Protection not to consume, drink, or cook with the water when at a level above 20PPT. Bottled water is recommended for consumption. Make sure to use tested bottled water (list available at 

What is considered a sensitive subgroup?

Those who are pregnant, nursing, have an infant under the age of 1, or are diagnosed by their health care provider to have a compromised immune system.

How often do we sample for PFAS6?

We are currently sampling monthly per DEP requirements. 

How will residents be alerted to any changes related to PFAS?

We will update our website as new information comes in.

Will boiling water for consumption improve the water quality?

No. Boiling the water will not destroy PFAS6. 

Who do I call with questions?

Residents are advised to contact their physician with questions specific to their indivual health situation. All other questions can be directed to the Town of Wilmington DPW Water Division at 978-658-4711.