We read 12 results from Cambridge Water Department’s 2025 water quality report. No results over a legal limit; 2 above a health goal or guideline.
Serves about 118,214 people · Water system ID MA3049000 · 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 |
|---|---|---|---|---|
| Bromatehighest running annual average · range ND to 2.1 · Treated water · 2025 report, page 5 | 0.5 ppb | 0.1 ppb | 10 ppb | Above the health goal5x the health goal |
| Lead90th percentile of homes tested, 0 over the action level · sampled 2023 · Customer taps · 2025 report, page 5 | 8 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal40x the health goal |
| Bariumsingle sample · Treated water · 2025 report, page 5 | 0.04 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chloraminehighest running annual average · range 1.88 to 2.94 · Distribution system · 2025 report, page 5 | 2.42 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested, 0 over the action level · sampled 2023 · Customer taps · 2025 report, page 5 | 0.04 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 2.8 to 10.9 · Distribution system · 2025 report, page 5 | 7.9 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 3.3 to 15.6 · Distribution system · 2025 report, page 5 | 8.6 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range 0.56 to 0.89 · Treated water · 2025 report, page 5 | 0.89 ppm | 1 ppm | 4 ppm | Below the health goal |
| Nitrate (as N)highest measured · range 0.24 to 0.43 · Treated water · 2025 report, page 5 | 0.43 ppm | 10 ppm | 10 ppm | Below the health goal |
| Total dissolved solidsaverage · Treated water · 2025 report, page 5 | 323 ppm | — | 500 ppm guideline | Within the guideline |
| Turbidity (cloudiness)highest measured · range 0.02 to 0.19 · Treatment plant · 2025 report, page 5 | 0.19 NTU | None set | 1 NTU | Below the legal limit |
| Sodiumaverage · Treated water · 2025 report, page 5 | 93.5 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 Cambridge Water Department’s water between Sep 2023 and Jun 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA4.8 pptFound in 1 of 4 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 (EPA testing)
What removes it: Reverse osmosis.
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