New Hampshire PFAS Standards Final …or Not???

December 30, 2019


 Drinking Water/Groundwater  

On September 30, 2019 in the State of New Hampshire, new Maximum Contaminant Levels (MCLs) and Ambient Groundwater Quality Standards (AGQS) went into effect for four (4) per- and polyfluoroalkyl substances (PFAS): 12 parts per trillion (ppt) for perfluorooctanoic acid (PFOA), 15 ppt for perfluorooctane sulfonic acid (PFOS), 18 ppt for perfluorohexane sulfonic acid (PFHxS), and 11 ppt for perfluorononanoic acid (PFNA).

On November 26, 2019, the State of New Hampshire Superior Court granted plaintiffs (including 3M Company and the Plymouth Village Water & Sewer District) preliminary injunctive relief prohibiting the New Hampshire Department of Environmental Services (DES) from enforcing these recently adopted MCLs and AGQS, effective December 31, 2019. In the opinion of the Court, relief was granted in recognition of the fact that “DES has not conducted an adequate cost-benefit analysis required by RSA 485:3, I(b).”

In response, on November 27, 2019, DES filed a Motion for Expedited Reconsideration, indicating that the AGQS be separated from the MCLs referenced in the injunctive relief as AGQS are not required by or included in RSA 485:3 I(b). If the motion for reconsideration is approved, the newly-promulgated AGQS will stand and continue to be enforced at contaminated sites in New Hampshire, while water system operators would have some relief from having to comply with MCLs until DES completes a further evaluation of the cost-benefit of compliance with these new, lower standards.


Revised Direct Contact Soil Concentrations 

On November 20, 2019, the New Hampshire Environmental Health Program (EHP) released direct contact risk-based (DCRB) soil concentrations for four (4) PFAS compounds (PFOA, PFOS, PFHxS and PFNA) considered protective of potential exposure in residential (S-1) and maintenance worker (S-2) scenarios. These range from 0.0.1 to 1.3 milligrams per kilogram (mg/kg) depending on the individual PFAS compound/scenario and provide an update to previously developed DCRB soil screening levels of 500 nanograms/gram (ng/g, equivalent to 0.5 mg/kg) for PFOA and PFOS. DCRB PFAS soil concentrations account for exposure that may result from incidental ingestion and dermal contact with impacted soil and can be found at this Link.


GeoInsight’s Expertise 

GeoInsight’s professionals include Professional Geologists and Engineers licensed in the State of New Hampshire. We have experience working on projects where emerging contaminants like PFAS are present and we have had experience working collaboratively with water system operators in the State to help understand the evolving regulatory landscape. Our staff have a solid understanding of the occurrence, chemistry, fate/transport and unique sampling, analytical and data validation requirements of PFAS, and will work together to bring practical, strategic solutions if PFAS are a concern on your site. 


If you have any questions about the evolving NH PFAS regulatory environment or to understand how/if these regulatory changes could impact your project – call us 800.217.1953

Michael Dacey, PG, Senior Consultant / NH Office Manager | 603.314.0820


Nikki Delude Roy, PG, Vice President | 603.314.0820