NHDES Groundwater Contamination Notification Within the Saint-Gobain Consent Decree Area

June 20, 2024

NHDES has recently identified a deficiency in our notification procedures within the Saint-Gobain Consent Decree Area. When contaminated groundwater that exceeds state Ambient Groundwater Quality Standards (AGQS) is discovered in a well, RSA 485-C:14-b requires NHDES to provide notification to the owners of all property that contains a water supply well and is located within 500 horizontal feet of the well where the contamination is discovered. Given the extensive number of impacted wells identified in several southern NH towns beginning back in 2016, and the pace at which contaminated wells were being identified, NHDES’s notification program was unprepared to make the extensive number of required notifications using our standard procedures in place at the time. Instead, we relied upon door-to-door sampling visits, post card and letter mailings, and extensive public outreach via our website and public meetings to inform residents.

As the per- and polyfluoroalkyl substances (PFAS) investigation has matured, and with the lowering of the applicable drinking water standard for perfluorooctanoic acid (PFOA) from 70 parts per trillion (ppt) to 12 ppt, beginning in September of 2019, the area under investigation expanded significantly, and many new wells have been and are being sampled. After developing more efficient and effective procedures for our notification program, we are now positioned to resume our standard notification practices for all instances where contamination is discovered in excess of AGQS, both inside and outside of the Consent Decree Area. We are taking immediate steps to notify all homes that are within 500 feet of an identified exceedance of AGQS within the Consent Decree Area. These notifications will be mailed out in April, and will include all properties located within a 500’ radius of a detected exceedance of the PFAS standards, even if prior notice has been provided, and regardless of whether the property is served by a private well or a public water system.

At this time, NHDES is not sampling wells in areas where Saint-Gobain has been identified as a party responsible for well testing due to release of PFAS from their facility (e.g., within the Consent Decree Area). Any parties who receive a notification and wish to have their well sampled for the first time are advised to contact Saint-Gobain’s hotline at 1-800-742-8498. Please note that it is currently taking 3 – 5 days for them to respond to messages left on the hotline. Alternatively, please contact Saint-Gobain’s environmental consultant (Golder Associates, Inc.) at NH.RWS@golder.com. Currently, Saint-Gobain is resampling wells on a limited basis where PFOA was previously detected at a concentration between 10 and 12 ppt and where additional criteria apply as described in Addendum 8 to the Water Supply Well Sampling Work Plan.

Please see the NHDES PFAS Investigation Website for additional information on the ongoing investigation and for Frequently Asked Questions about PFAS. If you have any general questions about the Saint-Gobain site investigation, please contact Jeffrey Marts of NHDES’ Hazardous Waste Remediation Bureau at (603) 271-6573.