Release: NHDES Proposes New PFAS Drinking Water Standards

News from the New Hampshire Department of Environmental Services


DATE: January 2, 2019   

CONTACT: Jim Martin, (603) 271-3710



NHDES Proposes New PFAS Drinking Water Standards

Initiates Rulemaking for PFOA, PFOS, PFHxS and PFNA

Concord, NH – On December 31, 2018, the New Hampshire Department of Environmental Services (NHDES) initiated rulemaking to establish Maximum Contaminant 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 deadline established in New Hampshire Chapter Laws 345 and 368 of 2018 (i.e. SB 309).

These MCLs are drinking water quality standards that non-transient public water systems (water systems serving the same 25 people at least 60 days a year) must comply with. An AGQS is the standard used to require remedial action and the provision of alternative drinking water at a contaminated site. It also dictates the conditions under which treated and untreated wastewater may be discharged to groundwater. Current law requires AGQSs be the same value as any MCL established by NHDES and also that they be as stringent as health advisories set by the U.S. Environmental Protection Agency (EPA). In 2016, NHDES adopted EPA’s health advisory for PFOA and PFOS as an AGQS ( 70 parts per trillion (ppt) combined).

To establish MCLs for PFOA, PFOS, PFHxS and PFNA, which by law then become AGQSs, NHDES had to also address the extent to which the contaminant is found in New Hampshire, the ability to detect the contaminant in public water systems, the ability to remove the contaminant from drinking water, and the costs and benefits to affected parties that will result from establishing the standard, and then develop a MCL for each compound that is protective of the most sensitive population at all life stages. The development of these standards was greatly enhanced by affected parties responding to NHDES’ request for studies and information to be considered in deriving the MCLs (

Using the most recent and best science available, NHDES is proposing the following drinking water standards that are protective of the most sensitive populations over a lifetime:


PFAS Proposed MCL and AGQS
PFOA 38 ppt
PFOS 70 ppt
PFOA & PFOS (combined) 70 ppt
PFHxS 85 ppt
PFNA 23 ppt

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 –

The majority of the work NHDES has performed to date has been focused on deriving the individual standards for PFOA, PFOS, PFNA and PFHxS that protect the most sensitive population through their lives. During the rulemaking process, NHDES expects to continue researching health studies on these chemicals as well as risk management approaches that are scientifically valid that could address any compounding effects between chemicals. Further exploration on quantifying benefit to affected parties will also occur. This continued effort will be done in tandem with considering public comments received on the initial rule proposal. NHDES recognizes and thanks the many stakeholder groups who have participated to date, and hopes they continue to be engaged throughout the public comment process.

Public hearings on the proposed MCLs will occur in southern NH, 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.


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