We read 9 results from Portsmouth Water Works’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 33,000 people · Water system ID NH1951010 · Read the district’s 2025 report (opens in a new tab)
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Results from the 2025 report
Each number is copied from the district’s report and links to the page it’s printed on. Where the report lists several plants, wells or purchased water, the highest is shown.
| Contaminant | Result | Health goal | Legal limit | What it means |
|---|---|---|---|---|
| Uraniumhighest measured · range ND to 1.6 · listed as a violation in the report · Sources · 2025 report, page 4 | 1.6 ppb | 0.6 ppb | 30 ppb | Above the health goal2.7x the health goal |
| Bariumaverage · range 0.009 to 0.03 · listed as a violation in the report · printed as 15 ppb · Sources · 2025 report, page 4 | 0.02 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorineaverage · range 0.04 to 1.6 · listed as a violation in the report · Distribution system · 2025 report, page 4 | 0.9 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 30 homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 4 | 0.12 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 30 to 79 · listed as a violation in the report · Distribution system · 2025 report, page 4 | 56 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 24 to 53 · listed as a violation in the report · Distribution system · 2025 report, page 4 | 43 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.56 to 0.75 · listed as a violation in the report · Treated water · 2025 report, page 4 | 0.63 ppm | 1 ppm | 4 ppm | Below the health goal |
| Lead90th percentile of 31 homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 4 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Nitrate (as N)average · range ND to 4 · listed as a violation in the report · Sources · 2025 report, page 4 | 0.7 ppm | 10 ppm | 10 ppm | Below the health goal |
Utility results describe the whole system, measured where water enters the pipes, not your tap. Your home’s plumbing can add lead or copper.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Portsmouth Water Works’s water between Jul 2023 and May 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA7 pptFound in 5 of 18 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFOS5 pptFound in 3 of 18 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFHxS5 pptFound in 3 of 18 samples · highest resultNo federal limit in force for this one
- PFBS9 pptFound in 5 of 18 samples · highest resultNo federal limit in force for this one
- Lithium10 ppbFound in 2 of 18 samples · highest resultBelow EPA’s health reference level of 10 ppb
Source: EPA UCMR 5 occurrence data. The highest single result is shown; one high sample doesn’t mean every glass is that high.
What you can do
Nothing here is an emergency notice: if the district has a violation, it must tell customers directly. If you’d like to lower these at your tap, these are the treatments that remove them, and the catalog shows the models certified for each. Ranking is by certified removal; commissions never change the order.
PFAS ("forever chemicals")
Found: PFOA (EPA testing), PFOS (EPA testing)
What removes it: Reverse osmosis.
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