We read 15 results from Dedham Westwood Water Dist.’s 2025 water quality report. No results over a legal limit; 5 above a health goal or guideline.
Serves about 41,630 people · Water system ID MA3073000 · 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 |
|---|---|---|---|---|
| Gross alpha (radioactivity)highest measured · range ND to 1.82 · sampled 2023 · Treated water · 2025 report, page 10 | 1.82 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Lead90th percentile of 31 homes tested, 1 over the action level · Customer taps · 2025 report, page 9 | 2 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal10x the health goal |
| PFOA (a PFAS)average · range 4.7 to 6.5 · printed as 0.005825 ppb · Treated water · 2025 report, page 12 | 5.83 ppt | 0.007 ppt | 20 ppt (Massachusetts) now; 4 ppt from 2029 | Above the federal limit that takes effect in 20291.5x the 4 ppt federal limit that takes effect in 2029; below the 20 ppt Massachusetts limit (for the sum of 6 PFAS)Not a violation yet: EPA's 4 ppt limit is final, but water systems don't have to meet it until 2029. |
| PFOS (a PFAS)average · range ND to 5.1 · printed as 0.003525 ppb · Treated water · 2025 report, page 12 | 3.53 ppt | 1 ppt | 20 ppt (Massachusetts) now; 4 ppt from 2029 | Above the health goal3.5x the health goal |
| Radium (combined 226 + 228)highest measured · sampled 2023 · Treated water · 2025 report, page 10 | 1.08 pCi/L | 0 pCi/L | 5 pCi/L | Above the health goalThe health goal is zero |
| Chlorideaverage · range 100 to 217 · Treated water · 2025 report, page 11 | 165 ppm | — | 250 ppm guideline | Within the guideline |
| Chlorinehighest running annual average · range ND to 2.86 · Distribution system · 2025 report, page 7 | 0.83 ppm | None set | 4 ppm | Below the legal limit |
| Disinfection byproducts (HAA5)highest running annual average · range 7.5 to 50.6 · Distribution system · 2025 report, page 9 | 42 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 8.9 to 91 · Distribution system · 2025 report, page 9 | 77 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.52 to 0.71 · Treated water · 2025 report, page 7 | 0.63 ppm | 1 ppm | 4 ppm | Below the health goal |
| Manganeseaverage · range ND to 0.05 · printed as 10.1 ppb · Treated water · 2025 report, page 11 | 0.01 ppm | — | 0.05 ppm guideline | Within the guideline |
| Nitrate (as N)average · range 0.52 to 1.39 · Treated water · 2025 report, page 7 | 0.96 ppm | 10 ppm | 10 ppm | Below the health goal |
| Hardnessaverage · range 4.33 to 7.84 · Treated water · 2025 report, page 10 | 6.08 gpg (104 ppm) | — | — | Moderately hard |
| PFAS (total of measured)highest running annual average · range 8 to 19.3 · Treated water · 2025 report, page 8 | 16.4 ppt | None set | None | No health limit |
| Sodiumaverage · range 63.6 to 107 · Treated water · 2025 report, page 10 | 84.9 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. 1 number we weren’t sure about is held back until a person checks.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Dedham Westwood Water Dist.’s water between Jan 2025 and Oct 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA6.5 pptFound in 4 of 8 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFOS5.1 pptFound in 3 of 8 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.
Radium and uranium
Found: Gross alpha (radioactivity), Radium (combined 226 + 228)
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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