Portsmouth Water Division offers update on PFAS regulations

January 3, 2019

On December 31, 2018, the New Hampshire Department of Environmental Services (NHDES) initiated rulemaking to establish Maximum Contaminate Levels (MCLs) and Ambient Groundwater Quality Standards (AGQS) for four per- and polyfluoroalkyl substances (PFAS) - perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA) and perfluorohexanesulfonic acid (PFHxS) to ensure greater protection of public health related to the consumption of drinking water. Specifically, NHDES filed a request for a fiscal impact statement for the new MCLs with the New Hampshire Legislative Budget Assistant, meeting the January 1, 2019 deadline established in New Hampshire Chapter Laws 345 and 368 of 2018 (i.e. SB 309).

These MCLs will be the drinking water quality standards that public water systems, including the City of Portsmouth’s, must comply with. Using the most recent and best science available, NHDES proposed the following drinking water standards that are protective of the most sensitive populations over a lifetime. Within the next few days, NHDES will release a summary report on the development of the drinking water standards (MCLs) including an explanation of the health risk assessment for each compound and information on cost, benefit, occurrence, and ability to detect and treat these chemicals. The report will be posted on the NHDES PFAS webpage: https://www4.des.state.nh.us/nh-pfas-investigation/.

Public hearings on the proposed MCLs will occur in southern New Hampshire, at Pease Tradeport, and at the NHDES offices in Concord in early March, which will provide the public more than a month to review the proposal and companion report. Depending on the comments received, it is anticipated that the final proposals will be filed by summer. The effective date of the new rules has yet to be determined.

The City of Portsmouth has been actively monitoring our source of supply water since the contamination of the Pease Haven, Smith and Harrison wells with PFAS was discovered in May 2014. The following table summarizes the most recent monitoring results, in Parts-per-Trillion (ppt) for the City of Portsmouth water sources. “ND” means that the sample result was “non-detect.”


The City of Portsmouth’s water supply staff will continue to monitor all of your public water supply sources for PFAS compounds every six months. Samples are sent to the same certified laboratory that has been analyzing PFAS since the contamination of the Pease Tradeport wells was discovered in May 2014.

The two currently active wells that serve the Pease Tradeport (the Smith and Harrison Wells) have activated carbon treatment in place. The most recent sampling of that treatment showed “ND” for all of these PFAS compounds.