Residents of a Portsmouth, New Hampshire neighborhood served by the former Pease Air Force Base water supply have faced questions about PFAS contamination in their drinking water for more than a decade, according to federal records and a series of health studies that have tracked chemical exposure at the site. Portsmouth's ZIP code 03801 carries a water record that reflects the city's history as one of the earliest American communities where contamination from the industrial compounds forced a municipal water shutdown.
In May 2014, when the Haven well at Pease was found to contain PFOS at levels more than 12 times a provisional safety threshold set by the Environmental Protection Agency, the city decided to shut it down. The base, which served as a Strategic Air Command facility and Air Force installation until 1991, is now home to a commercial airport, a golf course, and more than 250 businesses employing thousands of workers. Pease's transition to civilian use did not end its entanglement with the compounds left behind by decades of firefighting foam training exercises, which the military conducted routinely at the site.
The EPA record for the water system serving the Portsmouth area shows 3 violations in recent years, including 1 health-based violation, and lists PFAS as a flagged finding in the system's current profile. ZipCheckup's home safety profile for ZIP 03801 draws on EPA SDWIS and ECHO data current through April 2026 to surface that record alongside flood risk, radon indicators, and an overall safety score of 77 out of 100 -- a Grade B that nonetheless reflects ongoing water-quality questions the Haven well shutdown first made visible.
While PFOA and PFOS were the best-known compounds found at Pease, very little was known at the time about the other chemicals in their class. The revelation that PFOS had accumulated in people's blood led 3M to stop making the chemical in 2001. By 2006, the Environmental Protection Agency coordinated an industry-wide phase-out of PFOA and PFOS, both of which had been used in firefighting foam and various stain-resistant and nonstick products. Yet the compounds the foam deposited into the groundwater at Pease and hundreds of other military installations across the country were not going away. Several remained in commercial use and some had been offered as safe alternatives to PFOS and PFOA. The EPA had received additional studies from manufacturers raising health concerns about each of these chemicals but had yet to set enforceable safety limits for any of them.
The Agency for Toxic Substances and Disease Registry, working with New Hampshire health officials, eventually conducted blood testing for more than 1,600 residents and workers exposed to water from Pease. The results, released in 2015, showed that the average level of PFOS in children who drank from the Haven well was more than double the rate measured in a comparison group of children. Levels of PFHxS -- another compound found at the site -- were more than triple the national average among adults and five times higher than a comparison group among children. The findings from Pease became part of a CDC/ATSDR multi-site health study that has since examined exposure at military installations across the country.
The chemicals associated with the foam used at Pease are linked to cancer, reproductive and developmental harm, liver problems, and immune dysfunction. They stay in the body for years -- and persist in the environment indefinitely. And they had contaminated the water at Pease and spread into surrounding soil long before monitoring programs caught up with them. When the EPA finally set a nonbinding health advisory for PFOA and PFOS in 2016, it placed the threshold at 70 parts per trillion. Several states have since calculated lower limits. New Hampshire was among the first states to set enforceable maximum contaminant levels for PFAS compounds, adopting MCLs in 2019 and 2020 that applied to a broader set of compounds than the federal advisory had addressed, according to the New Hampshire Department of Environmental Services.
The amount of these chemicals deemed safe to ingest in drinking water has been dropping steadily, as is often the case as scientists learn more about how a chemical class affects human health. Between 2009 and 2016, the EPA's official threshold for PFOA in drinking water stood at 400 parts per trillion. In 2016, the agency lowered that figure to 70 ppt. In 2024, the EPA finalized federal MCLs for several PFAS compounds at levels far below its earlier health advisory, bringing national standards closer to what state regulators and researchers had been urging for years. For Portsmouth residents whose water systems continue to carry a flagged PFAS finding in federal databases, these regulatory shifts are not academic.
"It's infuriating that the more these PFAS manufacturers contaminate the planet, the more difficult it is to do effective human health studies, as there are fewer and fewer 'uncontaminated' populations to compare to," said Robert Bilott, the attorney whose class-action litigation against DuPont produced the first large-scale epidemiological panel studying PFOA's health effects. "It's as if, the more people they contaminate, the harder it is for those of us exposed to prove the harm from that exposure." Pease, which produced some of the earliest data on PFAS exposure in a civilian population, has remained a reference point in that ongoing scientific effort.