City of Palo Alto water quality

Updated 2026-10-22 · California · Affiliate disclosure

We read 7 results from City of Palo Alto’s 2025 water quality report. No results over a legal limit; 1 above a health goal or guideline.

Serves about 67,231 people · Water system ID CA4310009 · 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.

ContaminantResultHealth goalLegal limitWhat it means
Bromatehighest running annual average · range 1.9 to 4.1 · SFRWS treated water · 2025 report, page 63.5 ppb0.1 ppb10 ppbAbove the health goal35x the health goal
Chloraminehighest running annual average · range 0.44 to 3.41 · Distribution system · 2025 report, page 62.78 ppmNone set4 ppmBelow the legal limit
Copper90th percentile of 38 homes tested, 0 over the action level · printed as 61.9 ppb · sampled 2023 · Customer taps · 2025 report, page 70.06 ppm0.3 ppm1.3 ppm (action level)Below the health goal
Disinfection byproducts (HAA5)highest running annual average · range 9.8 to 71.6 · Distribution system · 2025 report, page 644 ppbNone set60 ppbBelow the legal limit
Disinfection byproducts (TTHM)highest running annual average · range 13 to 44 · Distribution system · 2025 report, page 635.8 ppbNone set80 ppbBelow the legal limit
Lead90th percentile of 38 homes tested, 0 over the action level · sampled 2023 · Customer taps · 2025 report, page 7Not detected0.2 ppb15 ppb (action level)Not detected
Nitrate (as N)average · range ND to 0.4 · SFRWS treated water · 2025 report, page 6Not detected10 ppm10 ppmNot detected

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.

Disinfection byproducts

Found: Bromate

What removes it: Carbon block.

See filters that remove it

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