PFAS in New Hampshire drinking water
20 drinking-water utilities in New Hampshire reported PFAS detections at or above the EPA minimum reporting level under UCMR 5 (the federal monitoring round that ran 2023–2025). Of those, 18 exceeded the final EPA Maximum Contaminant Level for PFOA or PFOS (4 parts per trillion), serving roughly 363,362 people.
By the numbers
- 20 New Hampshire water utilities with at least one PFAS compound detected
- 376,562 people served by those utilities
- 18 utilities above the final 4 ppt MCL for PFOA or PFOS
- 9 federal and Department of Defense sites with reported PFAS in groundwater
The interactive map below plots every reporting New Hampshire utility, colour-coded by whether their worst reading exceeds the federal MCL, sits below it but at or above the reporting threshold, or falls below the reporting threshold. Use the search box to find a specific utility, ZIP code or address.
Top New Hampshire water utilities by PFAS impact
The 15 New Hampshire public water systems with the most significant PFAS detections under UCMR 5, ranked by how far each system’s worst MCL-exceeding compound runs over the federal limit:
| # | Utility | Population served | Headline ng/L | Compound | vs MCL |
|---|---|---|---|---|---|
| 1 | Dover Water Dept, Nh | 29,000 | 120.0 | PFOS | 30.0× final MCL |
| 2 | Merrimack Village Dist | 25,000 | 20.0 | PFOA | 5.0× final MCL |
| 3 | Hudson Water Dept | 16,700 | 9.0 | PFOA | 2.3× final MCL |
| 4 | Rye Water Dist | 4,300 | 8.3 | PFOA | 2.1× final MCL |
| 5 | Salem Water Dept | 20,000 | 7.8 | PFOA | 1.9× final MCL |
| 6 | Hampstead Area Water | 6,953 | 7.5 | PFOS | 1.9× final MCL |
| 7 | Portsmouth Water Works | 33,000 | 7.0 | PFOA | 1.8× final MCL |
| 8 | Peu/Litchfield | 6,433 | 6.8 | PFOA | 1.7× final MCL |
| 9 | Jaffrey Water Works | 3,800 | 6.6 | PFOA | 1.6× final MCL |
| 10 | Pembroke Water Works | 5,200 | 6.5 | PFOS | 1.6× final MCL |
| 11 | Peu/Londonderry | 5,000 | 6.4 | PFOA | 1.6× final MCL |
| 12 | Exeter Water Dept | 12,236 | 6.0 | PFOA | 1.5× final MCL |
| 13 | Seabrook Water Dept | 14,000 | 5.3 | PFOS | 1.3× final MCL |
| 14 | Little Pond Estates | 2,730 | 5.2 | PFOA | 1.3× final MCL |
| 15 | Manchester Water Works, Nh | 123,500 | 5.0 | PFOA | 1.3× final MCL |
Use the interactive map above to find every utility (not just the top 15) and to search by ZIP code or address.
The biggest New Hampshire systems above the PFOA/PFOS MCL
Ranked by population served, the largest New Hampshire water utilities reporting at least one PFAS reading above EPA’s final MCL:
| # | Utility | Population served | Worst compound | Reading | vs MCL |
|---|---|---|---|---|---|
| 1 | Manchester Water Works, Nh | 123,500 | PFOA | 5.0 ng/L | 1.3× MCL |
| 2 | Aquarion Water/Nh | 34,000 | PFOA | 4.7 ng/L | 1.2× MCL |
| 3 | Portsmouth Water Works | 33,000 | PFOA | 7.0 ng/L | 1.8× MCL |
| 4 | Dover Water Dept, Nh | 29,000 | PFOS | 120.0 ng/L | 30.0× MCL |
| 5 | Merrimack Village Dist | 25,000 | PFOA | 20.0 ng/L | 5.0× MCL |
| 6 | Salem Water Dept | 20,000 | PFOA | 7.8 ng/L | 1.9× MCL |
| 7 | Derry Water Dept | 17,210 | PFOA | 4.2 ng/L | 1.1× MCL |
| 8 | Hudson Water Dept | 16,700 | PFOA | 9.0 ng/L | 2.3× MCL |
| 9 | Seabrook Water Dept | 14,000 | PFOS | 5.3 ng/L | 1.3× MCL |
| 10 | Exeter Water Dept | 12,236 | PFOA | 6.0 ng/L | 1.5× MCL |
PFAS compounds detected in New Hampshire
UCMR 5 required utilities to test for 29 different PFAS compounds. The table below shows how many New Hampshire utilities had at least one above-reporting-level result for each compound, sorted by frequency:
| Compound | New Hampshire utilities | Share of detecting utilities | EPA MCL |
|---|---|---|---|
| PFOA | 17 | 85% | 4 ppt (final) |
| PFHxA | 10 | 50% | None |
| PFOS | 9 | 45% | 4 ppt (final) |
| PFPeA | 8 | 40% | None |
| PFHpA | 5 | 25% | None |
| PFBA | 5 | 25% | None |
| PFBS | 4 | 20% | None |
| PFHxS | 2 | 10% | 10 ppt (April 2024, under reconsideration) |
Where New Hampshire’s PFAS contamination is coming from
EPA’s PFAS Analytic Tools also catalogue the suspected industrial, federal and accidental sources of PFAS in each state. New Hampshire has 9 federal facilities (mostly U.S. military installations and federal airports) reporting PFAS in groundwater, 19 EPA Superfund sites flagged for PFAS, and 3 recorded PFAS-related spills (2 of which reached surface water).
Federal and DoD sites with the highest PFAS in groundwater
The U.S. Department of Defense has reported PFAS contamination at hundreds of installations nationwide, largely tied to decades of fire-training exercises with PFAS-based firefighting foams (AFFF). These readings are taken from monitoring wells at the source site, not from drinking-water taps, but plumes from these sites are a known route into nearby public and private water supplies. Readings are in parts per trillion (ppt) of PFOS and PFOA respectively:
| Site | Agency | Max PFOS (groundwater) | Max PFOA (groundwater) |
|---|---|---|---|
| Pease AFB | Air Force | 490,000 ppt | 130,000 ppt |
| DFSP Newington | DLA | 23,800 ppt | 9 ppt |
| New Boston Space Force Station | Air Force | 520 ppt | 150 ppt |
Superfund sites flagged for PFAS in New Hampshire
EPA’s Superfund program has identified the following New Hampshire sites with confirmed PFAS detections:
- Auburn Road Landfill, Londonderry, Rockingham County. NPL status: Final. EPA site report
- Beede Waste Oil, Plaistow, Rockingham County. NPL status: Final. EPA site report
- Chlor-Alkali Facility (Former), Berlin, Coos County. NPL status: Final. EPA site report
- Coakley Landfill, North Hampton, Rockingham County. NPL status: Final. EPA site report
- Collins & Aikman Plant (Former), Farmington, Strafford County. NPL status: Final. EPA site report
Recent PFAS-related spills in New Hampshire
- 2025: Smoke released in Sandia (Rockingham County) by Copart.
- 2025: Fire fighting water and foam released in Sandia (Rockingham County) by Copart. Reached water.
- 2020: 5 gallons of firefighting foam released in Newington (Rockingham County) by New Hampshire Air National Guard. Reached water.
What “exceeds the MCL” means here
In April 2024 the EPA finalised the first-ever federal Maximum Contaminant Levels (MCLs) for six PFAS compounds in drinking water. The two most consequential are PFOA and PFOS, both set at 4.0 nanograms per litre (ng/L) — equivalent to 4 parts per trillion. Every red marker on the map above represents a New Hampshire water system whose most-recent UCMR 5 result for PFOA or PFOS sat above 4 ng/L.
EPA also issued individual MCLs of 10 ng/L for PFHxS, PFNA and HFPO-DA (GenX) and a Hazard-Index MCL covering mixtures. In May 2025 the agency confirmed the PFOA and PFOS limits would stay in place (with the compliance deadline extended to 2031), and announced its intent to rescind the four other limits. We continue to flag exceedances of the published April 2024 MCL for those compounds and label them as “under EPA reconsideration” so the rule status is honest and current.
Yellow markers mean PFAS were detected at or above EPA’s reporting threshold (the minimum reporting level) but no individual compound exceeded an MCL. Detection at any level is not necessarily a regulatory violation, but it is a signal that PFAS treatment may be needed before the 2031 compliance deadline.
Methodology and data sources
- Drinking-water detections: EPA PFAS Analytic Tools, UCMR 5 layer. Filtered to New Hampshire samples at or above the minimum reporting level. We aggregate the raw 2023–2025 sample records to one entry per public water system, taking the most-recent reading per compound.
- Superfund sites: EPA PFAS Analytic Tools, Superfund-with-PFAS layer. Includes National Priorities List sites and Superfund Alternative Approach sites where PFAS has been detected.
- Federal and DoD sites: EPA PFAS Analytic Tools, federal-sites layer. PFOA and PFOS values are maximum readings from groundwater monitoring wells at each installation, not finished drinking water.
- Spills: EPA PFAS Analytic Tools, spills layer. Covers reported releases involving PFAS-containing materials.
UCMR 5 only required community water systems serving 3,300 or more people, plus a representative sample of smaller systems, to test for PFAS. Private wells, very small public systems, and bottled water are not in this dataset. Absence of a dot on the map does not mean absence of PFAS.
What you can do
- Check whether your utility appears in the table above or on the map. If it does, your utility is required to come into compliance with the federal PFOA/PFOS MCL by 2031 — usually via granular activated carbon, ion-exchange resin or reverse osmosis treatment.
- If you are on a private well in or near a flagged area, consider independent PFAS testing through a state-certified laboratory.
- Look up your most recent Consumer Confidence Report (CCR), which utilities are required to publish annually. PFAS results from UCMR 5 must now appear there.
- If you want point-of-use protection, only filters certified to NSF/ANSI 53 or NSF/ANSI 58 for PFOA and PFOS reduction will reliably remove PFAS.
