We read 16 results from Aquarion-Greenwich’s 2025 water quality report. No results over a legal limit; 3 above a health goal or guideline.
Serves about 53,297 people · Water system ID CT0570011 · 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 |
|---|---|---|---|---|
| Chloritehighest measured · range ND to 0.58 · Distribution system · 2025 report, page 4 | 0.45 ppm | 0.05 ppm | 1 ppm | Above the health goal9x the health goal |
| Lead90th percentile of homes tested, 0 over the action level · Customer taps · 2025 report, page 3 | 2 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal10x the health goal |
| PFOA (a PFAS)average · range 4.5 to 5.3 · Entry points · 2025 report, page 5 | 4.8 ppt | 0.007 ppt | 4 ppt from 2029 | Above the federal limit that takes effect in 20291.2x the 4 ppt federal limit that takes effect in 2029Not a violation yet: EPA's 4 ppt limit is final, but water systems don't have to meet it until 2029. |
| Bariumaverage · range 0.03 to 0.04 · Entry points · 2025 report, page 3 | 0.03 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorideaverage · range 48 to 78 · Distribution system · 2025 report, page 4 | 57 ppm | — | 250 ppm guideline | Within the guideline |
| Chlorineaverage · range 0.01 to 1.88 · Distribution system · 2025 report, page 3 | 0.77 ppm | None set | 4 ppm | Below the legal limit |
| Chlorine dioxidehighest measured · range 20 to 620 · Treatment plant · 2025 report, page 3 | 199 ppb | None set | 800 ppb | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · Customer taps · 2025 report, page 3 | 0.18 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 19 to 59 · Distribution system · 2025 report, page 4 | 44 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 27 to 75 · Distribution system · 2025 report, page 4 | 56 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.57 to 0.85 · Entry points · 2025 report, page 3 | 0.7 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)average · range ND to 0.32 · Entry points · 2025 report, page 3 | 0.09 ppm | 10 ppm | 10 ppm | Below the health goal |
| PFOS (a PFAS)average · range ND to 4 · Entry points · 2025 report, page 5 | Not detected | 1 ppt | 4 ppt from 2029 | Not detected |
| Sulfateaverage · range 12 to 32 · Distribution system · 2025 report, page 4 | 26 ppm | — | 250 ppm guideline | Within the guideline |
| PFHxA (a PFAS)average · range ND to 3 · Entry points · 2025 report, page 5 | Not detected | None set | None | No health limit |
| Sodiumaverage · range 38 to 46 · Distribution system · 2025 report, page 4 | 40 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 Aquarion-Greenwich’s water between Oct 2024 and Aug 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA5.6 pptFound in 11 of 12 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFOS4.1 pptFound in 2 of 12 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
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: PFOA (a PFAS), PFOA (EPA testing), PFOS (EPA testing)
What removes it: Reverse osmosis.
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