We read 21 results from Clark Public Utilities’s 2025 water quality report. No results over a legal limit; 7 above a health goal or guideline.
Serves about 116,876 people · Water system ID WA5313333 · 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 |
|---|---|---|---|---|
| Arsenichighest measured · range ND to 4.1 · Wells · 2025 report, page 3 | 4.1 ppb | 0.004 ppb | 10 ppb | Above the health goal1,025x the health goal |
| Gross alpha (radioactivity)highest measured · range ND to 0.26 · Wells · 2025 report, page 3 | 0.26 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| Ironhighest measured · range ND to 0.32 · Wells · 2025 report, page 3 | 0.32 ppm | — | 0.3 ppm guideline | Above the guideline1.1x the guideline (taste, odor or stains; not a health limit) |
| Lead90th percentile of homes tested · Customer taps · 2025 report, page 3 | 3 ppb | 0.2 ppb | 15 ppb (action level) | Above the health goal15x the health goal |
| PFOA (a PFAS)highest measured · range ND to 3.92 · Well 10 (backup) · 2025 report, page 3 | 3.92 ppt | 0.007 ppt | 4 ppt from 2029 | Above the health goal560x the health goal |
| PFOS (a PFAS)highest measured · range ND to 3.99 · Well 10 (backup) · 2025 report, page 3 | 3.99 ppt | 1 ppt | 4 ppt from 2029 | Above the health goal4x the health goal |
| Radium-228highest measured · range ND to 0.88 · Wells · 2025 report, page 3 | 0.88 pCi/L | 0.02 pCi/L | 5 pCi/L | Above the health goal46x the health goal |
| Chloridehighest measured · range ND to 53 · Wells · 2025 report, page 3 | 53 ppm | — | 250 ppm guideline | Within the guideline |
| Copper90th percentile of homes tested · Customer taps, highest of 2 sources · 2025 report, page 3 | 0.14 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range ND to 4.1 · Distribution system · 2025 report, page 3 | 3.1 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range ND to 13 · Distribution system · 2025 report, page 3 | 12.6 ppb | None set | 80 ppb | Below the legal limit |
| Fluoridehighest measured · range ND to 0.23 · Wells · 2025 report, page 3 | 0.23 ppm | 1 ppm | 4 ppm | Below the health goal |
| Manganesehighest measured · range ND to 0.04 · Wells · 2025 report, page 3 | 0.04 ppm | — | 0.05 ppm guideline | Within the guideline |
| Nitrate (as N)highest measured · range ND to 2.7 · Wells · 2025 report, page 3 | 2.7 ppm | 10 ppm | 10 ppm | Below the health goal |
| PFHxS (a PFAS)highest measured · range ND to 2.56 · Well 10 (backup) · 2025 report, page 3 | 2.56 ppt | None set | 10 ppt from 2029 | Below the legal limit |
| Sulfatehighest measured · range ND to 5.7 · Wells · 2025 report, page 3 | 5.7 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidshighest measured · range ND to 150 · Wells · 2025 report, page 3 | 150 ppm | — | 500 ppm guideline | Within the guideline |
| Hardnessaverage · Wells · 2025 report, page 3 | 5.09 gpg (87 ppm) | — | — | Moderately hard |
| PFBS (a PFAS)highest measured · range ND to 2.21 · Well 10 (backup) · 2025 report, page 3 | 2.21 ppt | None set | None | No health limit |
| PFHxA (a PFAS)highest measured · range ND to 2 · Well 10 (backup) · 2025 report, page 3 | 2 ppt | None set | None | No health limit |
| Sodiumaverage · Wells · 2025 report, page 3 | 9.7 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 Clark Public Utilities’s water between Mar 2023 and Sep 2023. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA8 pptFound in 1 of 20 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFOS8.4 pptFound in 1 of 20 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFHxS5.3 pptFound in 1 of 20 samples · highest resultNo federal limit in force for this one
- PFBS4.1 pptFound in 1 of 20 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.
Radium and uranium
Found: Gross alpha (radioactivity), Radium-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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