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Review government records associated with Half Moon Bay, California.
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Check your water bill for your utility name and confirm the reporting year. See EPA’s guide to finding your annual water quality report.
Public water-system records for Half Moon Bay, CA from EPA SDWIS.
Coastside County Water District
No active drinking-water issues detected in EPA SDWIS.
Reviewed: active/open records as of Q1 2026
City listed in EPA records · Serves 18,940 people
City of San Bruno
No active drinking-water issues detected in EPA SDWIS.
Reviewed: active/open records as of Q1 2026
Purchased or imported water record · Serves 42,631 people
Sfpuc City Distribution Division
No active drinking-water issues detected in EPA SDWIS.
Reviewed: active/open records as of Q1 2026
Purchased or imported water record · Serves 848,019 people
Data from EPA SDWIS
Reviewed: source records as of Q1 2026
EPA UCMR5 — No PFAS detection records shown for these water systems
Open data source: EPA UCMR5DoD PFAS — No investigation records shown for this report
Open data source: DoD PFASEPA ATTAINS records identify assessed water bodies that do not meet water-quality standards for designated uses.
Arroyo Leon
Reported: Nov 2026
Health-relevant causes: Mercury
Affected uses: Ecological, Fishconsumption, Other
Data from EPA ATTAINS
NPDES permits regulate pollutant discharges into U.S. waterways. Facilities must report compliance quarterly.
Violation records
Last inspected: Dec 2025
Data from EPA ECHO
To investigate water contamination, check the sampling locations, dates and results below. For tap water records, see Drinking water quality above.
Reviewed: source records as of 2026
Review historical EPA air pollution records, including monitoring and facility emissions where available. For current conditions, check local air quality on AirNow.
San Mateo County
Assessment year: 2020
According to EPA, a cancer risk of 20-in-1-million means that for every 1 million people continuously exposed to these air toxics over a 70-year lifetime, an estimated 20 may develop cancer from that exposure. This is in addition to cancer risk from all other causes.
Top modeled source groups
Data from EPA AirToxScreen
EPA designations apply to a specific pollutant and federal air quality standard (NAAQS). EPA can issue a clean-data determination while a formal designation remains in effect.
San Francisco Bay Area: Ozone
NonattainmentMarginal8-Hour Ozone (2015 Standard)
Original designation: Aug 2018
Health effects (EPA): Respiratory inflammation, aggravation of asthma, reduced lung function (EPA)
San Francisco Bay Area: PM2.5
NonattainmentModeratePM-2.5 (2006 Standard)
Original designation: Dec 2009
Health effects (EPA): Cardiovascular disease, respiratory illness, premature death (EPA)
Maintenance areas
Previously nonattainment; currently meeting the standard and monitored under an EPA maintenance plan.
San Francisco-Oakland-San Jose Area
CO · Carbon Monoxide (1971 Standard)
Classification: Moderate <= 12.7ppm
Original designation: Nov 1990
Current design value: 4.9 ppm (2023-2025)
Data from EPA Green Book
Facilities regulated under the Clean Air Act. CAA HPV flags indicate serious noncompliance such as exceeding emission limits.
No facility records with active violation or noncompliance flags surfaced in EPA ECHO.
Reviewed: active/open records as of Q4 2025
Data from EPA ECHO
Reviewed: source query run Nov 2026
Reviewed: source query run Nov 2026
State environmental agencies maintain cleanup site databases that include state Superfund, voluntary cleanup, and brownfield remediation programs. These programs track additional sites beyond those on the federal NPL.
No state cleanup site records with active investigation or remediation status surfaced nearby.
Reviewed: active/open records as of CA DTSC EnviroStor (live query)
Data from EPA ECHO
No release reports shown in this group.
Reviewed: active/open records as of 2018
Data from EPA UST Finder
Formerly Used Defense Sites are properties previously owned by, leased to, or otherwise possessed by the United States and under the jurisdiction of the Secretary of Defense. The FUDS program addresses environmental restoration at these properties.
Open data source: USACE FUDSNo MSHA mine or extraction site records shown for this report.
San Mateo County, CA
EPA Radon Zone Map (June 2024 release)
San Mateo County is EPA Radon Zone 2 (moderate potential). EPA defines Zone 2 counties as having predicted average indoor screening levels between 2 pCi/L and 4 pCi/L.
Radon levels can vary from home to home, so EPA recommends testing the property to know its indoor level.
FEMA flood zones describe mapped flood hazards. Look up a specific address with FEMA.
Coastal Special Flood Hazard Area — 1% annual chance of flooding with additional coastal wave action hazards and base flood elevation.
Results use an earlier stored RMP inventory. Current EPA ECHO location coverage is unverified.
No EPA ECHO RMP facility records with a usable location matched this city report.
Health outcomes from County Health Rankings. Values shown alongside state and national averages.
San Mateo County, CaliforniaPop. 729,181
County Health Rankings edition: 2024
Premature Death
Poor or Fair Health
Poor Physical Health Days
Poor Mental Health Days
Adult Smoking
Adult Obesity
Air Pollution - Particulate Matter
Drinking water violation indicator
Diabetes Prevalence
Life Expectancy
| Indicator | County | State | National |
|---|---|---|---|
| Premature Death | 3,816 | 6,373 | 7,972 |
| Poor or Fair Health | 11.7% | 15.8% | 14.2% |
| Poor Physical Health Days | 2.6 | 3.1 | 3.3 |
| Poor Mental Health Days | 4.2 | 4.7 | 4.8 |
| Adult Smoking | 8.1% | 8.8% | 15.0% |
| Adult Obesity | 21.0% | 27.8% | 34.0% |
| Air Pollution - Particulate Matter | 7.0 | 7.1 | 7.3 |
| Drinking water violation indicator | No | N/A | N/A |
| Diabetes Prevalence | 8.8% | 10.8% | 9.6% |
| Life Expectancy | 84.5 | 79.9 | 77.6 |
This report does not have PFAS sample results for the candidate water systems in Half Moon Bay.
Check with the utility that serves your address for its testing results.
EPA drinking water records on this page list 5 violations for Coastside County Water District.
EPA drinking water records on this page list 1 violation for the City of San Bruno.
The EPA drinking water records available here list no violations for Sfpuc City Distribution Division.
Check your water bill to identify the utility serving your address. Ask that utility about current drinking water advisories.
We don't have air monitoring measurements for Half Moon Bay yet.
The radon data for Half Moon Bay covers San Mateo County. EPA places this area in Zone 2, with a predicted average indoor radon screening level of 2 to 4 picocuries per liter.
No Superfund or brownfield sites were returned for this city report.
The county data for Half Moon Bay reports a life expectancy of 84.5 years in San Mateo County, California.
The figure is from the 2024 edition of County Health Rankings, a University of Wisconsin program that publishes county health statistics.
The county data for Half Moon Bay reports 3,816 years of life lost to deaths before age 75 per 100,000 residents in San Mateo County, California. This measure adds up the years lost to early deaths and adjusts for differences in population age.
The figure is from the 2024 edition of County Health Rankings, a University of Wisconsin program that publishes county health statistics.
The county data for Half Moon Bay lists fine-particle pollution (PM2.5) at 7.0 micrograms per cubic meter in San Mateo County, California.
The figure is from the 2024 edition of County Health Rankings, a University of Wisconsin program that publishes county health statistics.