We read 11 results from Wallingford Water Department’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 37,267 people · Water system ID CT1480011 · 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 |
|---|---|---|---|---|
| Lead90th percentile of homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 6 | 9.8 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal49x the health goal |
| Bariumhighest measured · range 0.07 to 0.32 · listed as a violation in the report · Treated water · 2025 report, page 6 | 0.32 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloridehighest measured · range 20 to 109 · listed as a violation in the report · Treated water · 2025 report, page 6 | 109 ppm | — | 250 ppm guideline | Within the guideline |
| Chlorinehighest measured · range 0.25 to 1.84 · listed as a violation in the report · Distribution system · 2025 report, page 6 | 1.84 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2025 report, page 6 | 0.13 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 17.4 to 42.5 · listed as a violation in the report · Distribution system · 2025 report, page 6 | 29.7 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 25.5 to 94.2 · listed as a violation in the report · Distribution system · 2025 report, page 6 | 60.1 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range ND to 0.65 · listed as a violation in the report · Treated water · 2025 report, page 6 | 0.65 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range 0.07 to 3 · listed as a violation in the report · Treated water · 2025 report, page 6 | 3 ppm | 10 ppm | 10 ppm | Below the health goal |
| Sulfatehighest measured · range 9.5 to 22.6 · listed as a violation in the report · Treated water · 2025 report, page 6 | 22.6 ppm | — | 250 ppm guideline | Within the guideline |
| Sodiumhighest measured · range 16.2 to 47.9 · listed as a violation in the report · Treated water · 2025 report, page 6 | 47.9 ppm | None set | None | No health limit |
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 Wallingford Water Department’s water between Jul 2025 and Apr 2026. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOS13.9 pptFound in 2 of 8 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFHxS10.7 pptFound in 2 of 8 samples · highest resultNo federal limit in force for this one
- PFBS4 pptFound in 2 of 8 samples · highest resultNo federal limit in force for this one
- Lithium11.1 ppbFound in 1 of 8 samples · highest resultAbove EPA’s health reference level of 10 ppb (a guide, not a legal limit)
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.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
PFAS ("forever chemicals")
Found: PFOS (EPA testing)
What removes it: Reverse osmosis.
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