We read 9 results from City of Rialto’s 2024 water quality report. No results over a legal limit; 2 above a health goal or guideline.
Serves about 54,453 people · Water system ID CA3610038 · 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 |
|---|---|---|---|---|
| Arsenicaverage · City of Rialto wells · 2024 report, page 7 | 5.53 ppb | 0.004 ppb | 10 ppb | Above the health goal1,383x the health goal |
| Chromium-6average · range 0.16 to 2.8 · City of Rialto wells · 2024 report, page 7 | 1.25 ppb | 0.02 ppb | 10 ppb | Above the health goal63x the health goal |
| Bariumaverage · range 0.01 to 0.05 · sampled 2023 · City of Rialto wells · 2024 report, page 7 | 0.03 ppm | 2 ppm | 2 ppm | Below the health goal |
| Chlorineaverage · range 0.4 to 1.95 · City of Rialto distribution · 2024 report, page 12 | 1.06 ppm | None set | 4 ppm | Below the legal limit |
| Copper90th percentile of 30 homes tested · Customer taps · 2024 report, page 12 | 0.14 ppm | 0.3 ppm | 1.3 ppm (action level) | Below the health goal |
| Disinfection byproducts (HAA5)average · range ND to 5.3 · City of Rialto distribution · 2024 report, page 12 | 0.13 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)average · range ND to 12.8 · City of Rialto distribution · 2024 report, page 12 | 0.62 ppb | None set | 80 ppb | Below the legal limit |
| Lead90th percentile of 30 homes tested · Customer taps · 2024 report, page 12 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Nitrate (as N)average · range 1.1 to 4.9 · City of Rialto wells · 2024 report, page 7 | 2.85 ppm | 10 ppm | 10 ppm | Below the health goal |
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 City of Rialto’s water between Jul 2023 and Apr 2024. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA7.3 pptFound in 1 of 19 samples · highest resultAbove the federal limit that takes effect in 2029 (4 ppt)
- PFHxS3.5 pptFound in 2 of 19 samples · highest resultNo federal limit in force for this one
- PFBS4.6 pptFound in 2 of 19 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.
PFAS ("forever chemicals")
Found: PFOA (EPA testing)
What removes it: Reverse osmosis.
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