We read 16 results from Oildale Mwc’s 2025 water quality report. No results over a legal limit; 3 above a health goal or guideline.
Serves about 44,899 people · Water system ID CA1510015 · 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 ND to 2.5 · Treated water · 2025 report, page 2 | 1.1 ppb | 0.004 ppb | 10 ppb | Above the health goal275x the health goal |
| Gross alpha (radioactivity)average · Treated water · 2025 report, page 2 | 3.96 pCi/L | 0 pCi/L | 15 pCi/L | Above the health goalThe health goal is zero |
| PFOS (a PFAS)average · range ND to 5.8 · Wells · 2025 report, page 3 | 2.13 ppt | 1 ppt | 4 ppt from 2029 | Above the health goal2.1x the health goal |
| Chlorideaverage · range 5.92 to 39.1 · Treated water · 2025 report, page 2 | 15.6 ppm | — | 250 ppm guideline | Within the guideline |
| Chlorineaverage · range 0.5 to 1.7 · Distribution system · 2025 report, page 2 | 0.88 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of homes tested · sampled 2021 · Customer taps · 2025 report, page 3 | 0.09 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)average · range ND to 47.9 · Distribution system · 2025 report, page 2 | 39.5 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)average · range ND to 72.4 · Distribution system · 2025 report, page 2 | 51.1 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range ND to 0.2 · Treated water · 2025 report, page 2 | 0.12 ppm | 1 ppm | 2 ppm | Below the health goal |
| Lead90th percentile of homes tested · printed as ND ppm · sampled 2021 · Customer taps · 2025 report, page 3 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Nitrate (as N)average · range 0.13 to 0.25 · Treated water · 2025 report, page 2 | 0.21 ppm | 10 ppm | 10 ppm | Below the health goal |
| Sulfateaverage · range 19.1 to 56.1 · Treated water · 2025 report, page 2 | 35.5 ppm | — | 250 ppm guideline | Within the guideline |
| Total dissolved solidsaverage · range 86 to 219 · Treated water · 2025 report, page 2 | 130 ppm | — | 500 ppm guideline | Within the guideline |
| Hardnessaverage · range 2.26 to 5.21 · Treated water · 2025 report, page 3 | 3.43 gpg (58.7 ppm) | — | — | Soft |
| PFBS (a PFAS)average · range ND to 3.8 · Wells · 2025 report, page 3 | 0.63 ppt | None set | None | No health limit |
| Sodiumaverage · range 14.4 to 39.2 · Treated water · 2025 report, page 3 | 23.2 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.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in Oildale Mwc’s water between Feb 2023 and Nov 2023. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium12.2 ppbFound in 1 of 8 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 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)
What removes it: Reverse osmosis.
PFAS ("forever chemicals")
Found: PFOS (a PFAS)
What removes it: Reverse osmosis.
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