We read 16 results from Ctwc - Shoreline Region-Guilford System’s 2025 water quality report. No results over a legal limit; 5 above a health goal or guideline.
Serves about 33,975 people · Water system ID CT0608011 · 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 |
|---|---|---|---|---|
| Fluoridehighest measured · range ND to 1.24 · Entry points · 2025 report, page 7 | 1.24 ppm | 1 ppm | 4 ppm | Above the health goal1.2x the health goal |
| Lead90th percentile of 58 homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 9 | 1 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal5x the health goal |
| PFOA (a PFAS)highest measured · range ND to 7.8 · Entry points · 2025 report, page 8 | 7.8 ppt | 0.007 ppt | 4 ppt from 2029 | Above the federal limit that takes effect in 20292x 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. |
| PFOS (a PFAS)highest measured · range ND to 12 · Entry points · 2025 report, page 8 | 12 ppt | 1 ppt | 4 ppt from 2029 | Above the federal limit that takes effect in 20293x 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. |
| Uraniumhighest measured · range ND to 2.1 · Entry points · 2025 report, page 7 | 2.1 ppb | 0.6 ppb | 30 ppb | Above the health goal3.5x the health goal |
| Bariumhighest measured · range ND to 0.05 · Entry points · 2025 report, page 7 | 0.05 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloridehighest measured · range 7.1 to 89.1 · Entry points · 2025 report, page 7 | 89.1 ppm | — | 250 ppm guideline | Within the guideline |
| Chlorinehighest measured · range 0.01 to 1.54 · Distribution system · 2025 report, page 7 | 1.54 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 58 homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 9 | 0.3 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 11.8 to 34 · Distribution system · 2025 report, page 8 | 23.5 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 17 to 37.5 · Distribution system · 2025 report, page 8 | 40.4 ppb | None set | 80 ppb | Below the legal limit |
| Nitrate (as N)highest measured · range ND to 3.82 · Entry points · 2025 report, page 7 | 3.82 ppm | 10 ppm | 10 ppm | Below the health goal |
| PFHxS (a PFAS)highest measured · range ND to 4 · Entry points · 2025 report, page 8 | 4 ppt | None set | 10 ppt from 2029 | Below the legal limit |
| Sulfatehighest measured · range ND to 35.9 · Entry points · 2025 report, page 7 | 35.9 ppm | — | 250 ppm guideline | Within the guideline |
| Nickelhighest measured · range ND to 11 · Entry points · 2025 report, page 7 | 11 ppb | None set | None | No health limit |
| Sodiumhighest measured · range 7.9 to 81.6 · Entry points · 2025 report, page 7 | 81.6 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 Ctwc - Shoreline Region-Guilford System’s water between Mar 2024 and Sep 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA6 pptFound in 8 of 22 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFOS12 pptFound in 6 of 22 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFHxS4 pptFound in 1 of 22 samples · highest resultNo federal limit in force for this one
- PFBS5 pptFound in 3 of 22 samples · highest resultNo federal limit in force for this one
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.
Fluoride
Found: Fluoride
What removes it: Reverse osmosis.
Lead
Found: Lead
What removes it: Certified carbon block or RO.
PFAS ("forever chemicals")
Found: PFOA (a PFAS), PFOS (a PFAS), PFOA (EPA testing), PFOS (EPA testing)
What removes it: Reverse osmosis.
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