We read 25 results from Cal-Am Water Company - Duarte’s 2025 water quality report. No results over a legal limit; 8 above a health goal or guideline.
Serves about 24,773 people · Water system ID CA1910186 · 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 |
|---|---|---|---|---|
| Arsenicaverage · range 1.3 to 1.9 · Duarte Wells · 2025 report, page 5 | 1.6 ppb | 0.004 ppb | 10 ppb | Above the health goal400x the health goal |
| Chromium-6average · range 0.15 to 0.75 · sampled 2024 · Duarte Wells · 2025 report, page 5 | 0.34 ppb | 0.02 ppb | 10 ppb | Above the health goal17x the health goal |
| Gross alpha (radioactivity)average · range ND to 2.67 · Duarte Wells · 2025 report, page 5 | 0.87 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Lead90th percentile of 31 homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 3 | 1 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal5x the health goal |
| PFOA (a PFAS)average · range ND to 4.9 · Treatment plant effluent and/or sources · 2025 report, page 7 | 0.54 ppt | 0.007 ppt | 4 ppt from 2029 | Above the health goal77x the health goal |
| PFOS (a PFAS)average · range ND to 5.1 · Duarte Wells · 2025 report, page 8 | 1.3 ppt | 1 ppt | 4 ppt from 2029 | Above the health goal1.3x the health goal |
| Radium (combined 226 + 228)average · range ND to 1.3 · sampled 2024 · Duarte Wells · 2025 report, page 5 | 0.08 pCi/L | 0 pCi/L | 5 pCi/L | Above the health goalThe health goal is zero |
| Uraniumaverage · range 0.83 to 2.53 · printed as 1.03 pCi/L · Duarte Wells · 2025 report, page 5 | 1.54 ppb | 0.6 ppb | 30 ppb | Above the health goal2.6x the health goal |
| Aluminumaverage · range ND to 0.04 · printed as 5.3 ppb · Duarte Wells · 2025 report, page 6 | 0.0053 ppm | — | 0.2 ppm guideline | Within the guideline |
| Chlorideaverage · range 24 to 50 · Duarte Wells · 2025 report, page 6 | 36 ppm | — | 250 ppm guideline | Within the guideline |
| Chlorinehighest running annual average · range 0.99 to 1.31 · Distribution system · 2025 report, page 4 | 1.16 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 31 homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 3 | 0.13 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range ND to 2.2 · Distribution system · 2025 report, page 4 | 1.6 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 2 to 17 · Distribution system · 2025 report, page 4 | 9.8 ppb | None set | 80 ppb | Below the legal limit |
| Ironaverage · range ND to 0.13 · printed as 42 ppb · Duarte Wells · 2025 report, page 6 | 0.04 ppm | — | 0.3 ppm guideline | Within the guideline |
| Nitrate (as N)average · range 0.22 to 4.7 · Duarte Wells · 2025 report, page 5 | 1.15 ppm | 10 ppm | 10 ppm | Below the health goal |
| PFHxS (a PFAS)average · range ND to 1.6 · Duarte Wells · 2025 report, page 8 | 0.4 ppt | None set | 10 ppt from 2029 | Below the legal limit |
| Sulfateaverage · range 22 to 43 · Duarte Wells · 2025 report, page 6 | 30 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidsaverage · range 180 to 390 · Duarte Wells · 2025 report, page 6 | 249 ppm | — | 500 ppm guideline | Within the guideline |
| Turbidity (cloudiness)average · range ND to 0.5 · Duarte Wells · 2025 report, page 6 | 0.21 NTU | None set | 1 NTU | Below the legal limit |
| Hardnessaverage · Duarte Wells · 2025 report, page 6 | 7.54 gpg (129 ppm) | — | — | Hard |
| PFBA (a PFAS)average · range ND to 2 · Duarte Wells · 2025 report, page 8 | 0.7 ppt | None set | None | No health limit |
| PFBS (a PFAS)average · range ND to 2.5 · Duarte Wells · 2025 report, page 8 | 0.5 ppt | None set | None | No health limit |
| PFHxA (a PFAS)average · range ND to 1.4 · Duarte Wells · 2025 report, page 8 | 0.3 ppt | None set | None | No health limit |
| PFPeA (a PFAS)average · range ND to 1 · Duarte Wells · 2025 report, page 8 | 0.3 ppt | 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 Cal-Am Water Company - Duarte’s water between Oct 2023 and Mar 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOS5.1 pptFound in 1 of 16 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), Uranium
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), PFOS (EPA testing)
What removes it: Reverse osmosis.
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