Water quality · ZIP 94025
Water quality in Menlo Park, CA
ZIP 94025 is in San Mateo County, California. The largest community water system EPA lists there, CITY OF DALY CITY (serving about 104,901 people), reported no health-based violations in the last 3 years. EPA lists 8 active systems in the county, so your home may be on a different one. This is the utility's federal record, not a test of the water at any address.
San Mateo County, California · EPA SDWIS
CITY OF DALY CITY
PWSID CA4110013 · population served 104,901 · surface water · 8 active systems on record for this county; showing the largest by population served
- Health-based violations (3y)
- 0
- Total violations (3y)
- 0
No health-based violations reported in the last 3 years for this system.
This is federal SDWIS reporting data for the community water system serving this county, not an address-level test result. Private well water is never covered by SDWIS. Where a county is served by multiple systems, this shows the one serving the most people.
Next step for your own home
What this page shows
The community water system serving this ZIP's county, its EPA SDWIS record, and any health-based violations in the last 3 years — shown above.
Source & refresh
EPA SDWIS. States report water-system records to EPA every quarter. The violation counts here cover the last 3 years. Primary source →
Limitations specific to this source
Where a county has several water systems, zipradar shows the one serving the most people and says how many others are on record; yours may be a different one. Private well water is not covered.
California context
Wildfire (WUI), seismic, water-supply variability
California carries the highest concentrated WUI wildfire risk in the US per USFS WHP, with FAIR Plan + non-renewal pressure intensifying since 2017 fires. FEMA NFHL coverage is strong; drinking-water systems vary from large urban (LADWP, EBMUD) to small disadvantaged community systems flagged in EPA SDWIS. Radon risk is mostly Zone 2-3.
See California state page for the full state-level rollup across all 12 dimensions.
Read more on water quality
Editorial deep-dives explaining the source data, its limits, and how to read it.
Flood zones explained — what AE, X, and VE actually mean
Plain-English guide to FEMA flood-zone codes (A, AE, AH, V, VE, X, X-shaded). What the 1% and 0.2% annual-chance zones mean for your property and your insurance.
EPA Radon Zones — what 1, 2, and 3 mean and when you should test
EPA classifies every US county into Zone 1 (high), Zone 2 (moderate), or Zone 3 (low) for radon. Plain-English guide to the classifications and at-home testing.
EPA AQI categories explained — what 0–50 Good through 301–500 Hazardous mean
Plain-English guide to the six EPA Air Quality Index categories: 0–50 Good, 51–100 Moderate, 101–150 Unhealthy for Sensitive Groups, 151–200 Unhealthy, 201–300 Very Unhealthy, 301–500 Hazardous — what each level means and who is at risk.
Lead and Copper Rule 2024 — the federal lead-pipe inventory mandate
The 2024 Lead and Copper Rule Revisions (LCRR) require every US community water system to inventory and report lead service lines. Plain-English guide.
The other dimensions for ZIP 94025
Water quality is one of twelve public-records dimensions zipradar indexes per address. See the ZIP 94025 index for the other eleven — each with its own regulator, source and link:
All dimensions for Menlo Park, CA →Frequently asked questions
What is the water quality for ZIP 94025?
San Mateo County, California (which covers ZIP 94025) is served by CITY OF DALY CITY (EPA PWSID CA4110013), a community water system serving a reported population of 104,901. Health-based violations in the last 3 years: 0. This is federal SDWIS reporting data for the community water system serving this county, not an address-level test result. Private well water is never covered by SDWIS. Where a county is served by multiple systems, this shows the one serving the most people.
Where does the water quality data come from?
Source: EPA SDWIS. States report water-system records to EPA every quarter. The violation counts here cover the last 3 years. The original is at https://www.epa.gov/ground-water-and-drinking-water/safe-drinking-water-information-system-sdwis-federal-reporting.
What are the limitations of water quality data?
Where a county has several water systems, zipradar shows the one serving the most people and says how many others are on record; yours may be a different one. Private well water is not covered.
Is ZIP 94025 (Menlo Park) data current?
zipradar last checked this page against the source on 2026-09-24. States report water-system records to EPA every quarter. The violation counts here cover the last 3 years. The ZIP 94025 overview at /zip/94025/ lists the other topics zipradar covers for this ZIP.