We read 14 results from Santa Margarita Water District’s 2025 water quality report. No results over a legal limit; 4 above a health goal or guideline.
Serves about 168,289 people · Water system ID CA3010101 · Read the district’s 2025 report (opens in a new tab)
Open this district in the water lookupCompare with your own test results, see the district map and get matched filters.
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 2.2 · IRWD Baker plant · 2025 report, page 6 | 2.2 ppb | 0.004 ppb | 10 ppb | Above the health goal550x the health goal |
| Bromateaverage · range ND to 8.4 · Metropolitan Diemer plant · 2025 report, page 7 | 2.4 ppb | 0.1 ppb | 10 ppb | Above the health goal24x the health goal |
| Total dissolved solidsaverage · range 510 to 680 · Distribution system · 2025 report, page 5 | 614 ppm | — | 500 ppm guideline | Above the guideline1.2x the guideline (taste, odor or stains; not a health limit) |
| Uraniumaverage · printed as 1.9 pCi/L · IRWD Baker plant, highest of 2 sources · 2025 report, page 6 | 2.83 ppb | 0.6 ppb | 30 ppb | Above the health goal4.7x the health goal |
| Chlorineaverage · range 1.61 to 1.99 · Distribution system · 2025 report, page 5 | 1.83 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 52 homes tested, 0 over the action level · sampled 2024 · Customer taps (52 homes) · 2025 report, page 5 | 0.08 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)highest running annual average · range 4.1 to 10 · Distribution system · 2025 report, page 5 | 8 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)highest running annual average · range 20 to 37 · Distribution system · 2025 report, page 5 | 32 ppb | None set | 80 ppb | Below the legal limit |
| Fluorideaverage · range 0.6 to 0.8 · Metropolitan Diemer plant, highest of 2 sources · 2025 report, page 7 | 0.7 ppm | 1 ppm | 2 ppm | Below the health goal |
| Lead90th percentile of 52 homes tested, 0 over the action level · sampled 2024 · Customer taps (52 homes) · 2025 report, page 5 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Turbidity (cloudiness)highest measured · Metropolitan Diemer plant, highest of 2 sources · 2025 report, page 7 | 0.05 NTU | None set | 1 NTU | Below the legal limit |
| Hardnessaverage · range 12.3 to 17.5 · Distribution system · 2025 report, page 5 | 15 gpg (256 ppm) | — | — | Very hard |
| Lithiumaverage · range 30 to 47 · Metropolitan Diemer plant · 2025 report, page 7 | 38 ppb | None set | None | No health limit |
| Sodiumaverage · range 83 to 110 · Distribution system · 2025 report, page 5 | 95 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 Santa Margarita Water District’s water between Sep 2024 and Jun 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- Lithium50.1 ppbFound in 8 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.
Salty taste / high TDS
Found: Total dissolved solids
What removes it: Reverse osmosis.
More districts: California water quality · All states · Something look wrong? Tell us