We read 4 results from City of Tustin’s 2024 water quality report. No results over a legal limit or above a health goal.
Serves about 66,600 people · Water system ID CA3010046 · Read the district’s 2024 report (opens in a new tab)
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Results from the 2024 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 |
|---|---|---|---|---|
| Chlorineaverage · range 0.69 to 1.5 · listed as a violation in the report · Distribution system · 2024 report, page 5 | 1.17 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 48 homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2024 report, page 5 | 0.17 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Lead90th percentile of 48 homes tested, 0 over the action level · listed as a violation in the report · Customer taps · 2024 report, page 5 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Turbidity (cloudiness)highest measured · listed as a violation in the report · MWD Diemer plant · 2024 report, page 7 | 0.06 NTU | None set | 1 NTU | Below the legal 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. 2 numbers we weren’t sure about are held back until a person checks.
EPA testing for PFAS and lithium
EPA’s own nationwide testing (UCMR 5) found these in City of Tustin’s water between Mar 2023 and Nov 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOS4.2 pptFound in 1 of 14 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFHxS3.5 pptFound in 2 of 14 samples · highest resultNo federal limit in force for this one
- Lithium37.9 ppbFound in 9 of 14 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.
PFAS ("forever chemicals")
Found: PFOS (EPA testing)
What removes it: Reverse osmosis.
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