We read 3 results from Presidio of San Francisco’s 2025 water quality report. No results over a legal limit or above a health goal.
Serves about 3,500 people · Water system ID CA3810700 · 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 |
|---|---|---|---|---|
| Disinfection byproducts (HAA5)as reported · range 0.2 to 18.6 · 2025 report, page 6 | 17 ppb | None set | 60 ppb | Below the legal limit |
| Disinfection byproducts (TTHM)as reported · range 38 to 51.2 · 2025 report, page 6 | 50 ppb | None set | 80 ppb | Below the legal limit |
| Nitrate (as N)as reported · range 1.66 to 6.96 · 2025 report, page 6 | 6.96 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 Presidio of San Francisco’s water between Mar 2025 and Dec 2025. These are EPA lab results, separate from the district’s report. Anything not listed was not detected.
- PFOA4 pptFound in 1 of 4 samples · highest resultBelow the federal limit that takes effect in 2029 (4 ppt)
- PFHxS4.6 pptFound in 4 of 4 samples · highest resultNo federal limit in force for this one
- PFBS4.9 pptFound in 4 of 4 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 in this report is above a health goal or legal limit. If you’re bothered by taste, smell, hardness or spots, or your home has older pipes, the filter catalog and buyer questions can help you pick, and a test of your own tap shows what your plumbing adds.
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