We read 4 results from Cwsc Oak Hills’s 2025 water quality report. No results over a legal limit or above a health goal.
Serves about 3,161 people · Water system ID CA2710019 · 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 |
|---|---|---|---|---|
| Chlorideaverage · range 73 to 190 · 2025 report, page 14 | 132 ppm | — | 250 ppm guideline | Within the guideline |
| Ironaverage · range ND to 0.12 · printed as ND ppb · 2025 report, page 14 | Not detected | — | 0.3 ppm guideline | Not detected |
| Sulfateaverage · range 20 to 78 · 2025 report, page 14 | 49 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidsaverage · range 360 to 640 · 2025 report, page 14 | 500 ppm | — | 500 ppm guideline | Within the guideline |
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 Cwsc Oak Hills’s water between May 2023 and Dec 2023. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium28.7 ppbFound in 4 of 4 samples · highest resultAbove EPA’s health reference level of 10 ppb (a guide, not a legal limit)
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 in this report is above a health goal or legal limit. If you’re bothered by taste, smell, hardness or spots, or your home has older pipes, the filter catalog and buyer questions can help you pick, and a test of your own tap shows what your plumbing adds.
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