Per- and Polyfluoroalkyl Substances (PFAS)

On September 24, 2020, the Massachusetts Department of Environmental Protection (MassDEP) announced the final regulations for PFAS in drinking water and continue to clarify how laboratory results should be calculated and reported.  The MassDEP press release can be found here:  In October 2020, MassDEP promulgated a new drinking water standard for the sum of six PFAS compounds (PFAS6).  This new standard requires all Massachusetts public water suppliers test for PFAS.  The sum of PFAS6 may not exceed 20 nanograms per liter (ng/L), also equal to 20 parts per trillion (ppt).  Federal Drinking water standards do not currently regulate PFAS.

The Department is testing for the presence of the PFAS6 and will make those results available to the public after they are returned by the laboratory and confirmed by follow-up testing.  We anticipate this information will be available in January 2021.  The Department already tests regularly for hundreds of regulated and unregulated contaminants, and if above the standard, or maximum contaminant level (MCL), takes necessary measures to treat the drinking water. 

With relatively recent advances in laboratory testing, the presence of PFAS can be found in parts per trillion whereas in the past it would be undetected in parts per million or billion.  In 2013, the Department tested for PFAS at the higher level parts per billion and found no detects. 


According to the United States Environmental Protection Agency, PFAS are a group of man-made chemicals that includes PFOA, PFOS, GenX, and many other chemicals. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s. PFOA and PFOS have been the most extensively produced and studied of these chemicals. Both chemicals are very persistent in the environment and in the human body – meaning they don’t break down and they can accumulate over time. There is evidence that exposure to PFAS can lead to adverse human health effects.

PFAS can be found in:

  • Food packaged in PFAS-containing materials, processed with equipment that used PFAS, or grown in PFAS-contaminated soil or water.
  • Commercial household products, including stain- and water-repellent fabrics, nonstick products (e.g., Teflon), polishes, waxes, paints, cleaning products, and fire-fighting foams (a major source of groundwater contamination at airports and military bases where firefighting training occurs).
  • Workplace, including production facilities or industries (e.g., chrome plating, electronics manufacturing or oil recovery) that use PFAS.
  • Drinking water, typically localized and associated with a specific facility (e.g., manufacturer, landfill, wastewater treatment plant, firefighter training facility).
  • Living organisms, including fish, animals and humans, where PFAS have the ability to build up and persist over time.

Certain PFAS chemicals are no longer manufactured in the United States as a result of phase outs including the PFOA Stewardship Program in which eight major chemical manufacturers agreed to eliminate the use of PFOA and PFOA-related chemicals in their products and as emissions from their facilities. Although PFOA and PFOS are no longer manufactured in the United States, they are still produced internationally and can be imported into the United States in consumer goods such as carpet, leather and apparel, textiles, paper and packaging, coatings, rubber and plastics.


In order to understand what a chemical measurement means, one needs to have a basic understanding of the type of measuring units used, and what they mean. As mentioned above, most of our contaminants are measured using concentration units such as ppm and ppb.  But what is a ppm, ppb, or ppt for that matterin plain English?

As an example, let’s use an example of liquid chlorine added to our water in the treatment process at 1.0 ppm. This value refers to one part of chemical (in this case liquid chlorine) found in one million parts of our water. To realize how small a value this actually is and how difficult this contaminate 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)


To receive future updates regarding PFAS please sign up for the free WaterSmart notification program at: . This free water use tracking tool helps residents monitor usage, identify leaks, conserve water, and receive notifications regarding your water supply.

Specific questions may also be sent to with “PFAS” in the subject line.