We read 9 results from San Juan Water District’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.
Serves about 29,598 people · Water system ID CA3410021 · 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 |
|---|---|---|---|---|
| Copper90th percentile of 31 homes tested, 0 over the action level · sampled 2024 · Customer taps · 2025 report, page 5 | 0.35 ppm | 0.3 ppm | 1.3 ppm (action level) | Above the health goal1.2x the health goal |
| Chlorineaverage · range 0.14 to 1.12 · San Juan distribution · 2025 report, page 5 | 0.72 ppm | None set | 4 ppm | Below the legal limit |
| Disinfection byproducts (HAA5)average · range 19 to 62 · San Juan distribution · 2025 report, page 5 | 44 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)average · range 38 to 61 · San Juan distribution · 2025 report, page 5 | 53.3 ppb | None set | 80 ppb | Below the legal limit |
| Lead90th percentile of 31 homes tested, 1 over the action level · sampled 2024 · Customer taps · 2025 report, page 5 | Not detected | 0.2 ppb | 15 ppb (action level) | Not detected |
| Total dissolved solidsaverage · San Juan surface water · 2025 report, page 6 | 31 ppm | — | 500 ppm guideline | Within the guideline |
| Turbidity (cloudiness)highest measured · San Juan treatment plant · 2025 report, page 5 | 0.03 NTU | None set | 1 NTU | Below the legal limit |
| Hardnessaverage · San Juan surface water · 2025 report, page 6 | 0.99 gpg (17 ppm) | — | — | Soft |
| Sodiumaverage · San Juan surface water · 2025 report, page 6 | 2.2 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.
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.
Copper
Found: Copper
What removes it: Reverse osmosis.
More districts: California water quality · All states · Something look wrong? Tell us