Rockingham County in southeastern New Hampshire has a population of about 315,000, making it the state's most populous county.
Rockingham County in southeastern New Hampshire has a population of about 315,000, making it the state's most populous county. Communities from Salem to Portsmouth rely on a mix of surface water and groundwater. Pease International Tradeport – the former Pease Air Force Base – in Portsmouth became one of the first PFAS contamination cases to gain national attention and has shaped New Hampshire's aggressive regulatory response.
Pease AFB's PFAS contamination was identified in 2014, making it one of the earliest documented cases of military PFAS in drinking water. According to the New Hampshire DES's 2024 environmental fact sheet, PFOS was detected in the Haven well at Pease at concentrations exceeding 2,100 ppt before the well was shut down. The contamination affected the on-site daycare, businesses, and surrounding residential areas.
New Hampshire subsequently adopted some of the strictest PFAS standards in the country: 12 ppt for PFOA, 15 ppt for PFOS, with additional limits for PFHxS and PFNA. According to NHDES's 2024 statewide PFAS report, eight public water systems in Rockingham County have detected PFAS above state MCLs, requiring treatment. The Pease case also prompted the CDC/ATSDR to conduct a health study of affected residents.
Rockingham County has been at the leading edge of PFAS awareness and response. If you are near Pease or in one of the affected communities, your water system has likely already installed treatment. Household filtration adds another layer.
Check your water for current data on your system. For PFAS, reverse osmosis or activated carbon filters certified to NSF P473 are effective. Our water filter guide details the options. Pull your detailed report for historical context, and visit our New Hampshire page for statewide data.