Home hazard report for 94503 — American Canyon, CA
ZIP 94503 is served by City of American Canyon: 9 violations since 2016, latest lead result 0 ppb, PFAS not detected. Napa County is in EPA radon zone 3.
Health-based violations since 2016: Tthm. All are listed as resolved.
90th-percentile lead in the latest round (Jan 2022). Lead comes mostly from household plumbing and service lines, so individual homes can be higher.
None of the tested PFAS were found above EPA’s reporting limits in 2023–2025.
Predicted average under 2 pCi/L — but any home can have high radon, so EPA still recommends a test.
FEMA’s overall natural-hazard risk for this census tract, relative to the rest of the U.S.
No active Superfund site within 10 miles of the ZIP center.
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Where ZIP 94503 is
Dashed: ZIP area · blue: utility service area · scroll or pinch to zoomDrinking water: City of American Canyon
Health-based violations
| Contaminant or rule | Health-based violations since 2016 |
|---|---|
| Tthm | 9 |
A health-based violation means a contaminant exceeded its legal limit (MCL) or a required treatment technique was not met, as reported by the state to EPA’s SDWIS. All are listed as resolved or archived; the latest began Oct 2019.
Lead
90th-percentile lead per sampling round (90% of the homes sampled were at or below this level). Black line: EPA’s 15 ppb action level; under the Lead and Copper Rule Improvements the action level becomes 10 ppb from 2027.
PFAS (“forever chemicals”)
| Compound | Highest result | Samples with detection | EPA limit |
|---|---|---|---|
| PFNA | not detected | 0 of 3 | — |
| PFHxA | not detected | 0 of 3 | — |
| PFDA | not detected | 0 of 3 | — |
| PFHpA | not detected | 0 of 3 | — |
| PFOS | not detected | 0 of 3 | 4 ppt MCL |
| PFHxS | not detected | 0 of 3 | — |
| PFBS | not detected | 0 of 3 | — |
| PFOA | not detected | 0 of 3 | 4 ppt MCL |
| HFPO-DA (GenX) | not detected | 0 of 3 | — |
| PFPeA | not detected | 0 of 3 | — |
| PFBA | not detected | 0 of 3 | — |
EPA Fifth Unregulated Contaminant Monitoring Rule (UCMR 5), samples 2023–2025; ppt = parts per trillion (ng/L). The 4.0 ppt maximum contaminant levels for PFOA and PFOS were set by EPA in 2024; water systems have until the end of the decade to comply.
Radon in Napa County
EPA radon zone 3 — low potential. Predicted average under 2 pCi/L — but any home can have high radon, so EPA still recommends a test.
Radon is a colorless, odorless radioactive gas from soil and rock, and the leading cause of lung cancer among non-smokers. EPA recommends fixing a home at 4 pCi/L or above and considering it from 2 pCi/L. A short-term test kit costs about $15–30. How radon zones work →
Natural hazard risk
FEMA rates the overall natural-hazard risk of this neighborhood (census tract) as Very High, with relatively high social vulnerability and relatively high community resilience.
FEMA National Risk Index (December 2025): expected annual losses from each hazard combined with social vulnerability and community resilience, rated relative to all U.S. census tracts. Hazards not listed are not applicable here. It describes the area, not a single building; flood insurance maps (FEMA FIRMs) decide flood-insurance requirements.
Live conditions: river gauges and flood levels · tornado warnings · wildfire detections · earthquakes — our sister maps, updated from NOAA, USGS and NASA every few minutes.
Superfund sites nearby
No site on EPA’s Superfund National Priorities List lies within 10 miles of the center of this ZIP code.
EPA Superfund National Priorities List (NPL): the country’s most serious known hazardous-waste sites, each with an EPA cleanup record (linked). Distance is measured from the ZIP center to the site’s reference point; being near a site does not by itself mean exposure — EPA site pages describe what was found and how it is being cleaned up.
What this is — and isn’t. These are records your water utility and state reported to the EPA, and the EPA’s radon map for your county. They describe the system and the area, not the water from your own tap or the air in your home. For that, read your utility’s annual Consumer Confidence Report and test: lead and radon tests are inexpensive.
Questions about 94503
Who supplies drinking water to ZIP 94503?
City of American Canyon (EPA ID CA2810005), a surface water (rivers, lakes) system serving about 18,423 people.
Is there lead in American Canyon, CA tap water?
The utility’s latest 90th-percentile lead result (Jan 2022) was 0 ppb; EPA’s action level is 15 ppb, falling to 10 ppb from 2027. Lead mostly comes from service lines and home plumbing, so the only way to know your tap is to test it.
Does American Canyon, CA water have PFAS?
None of the tested PFAS were found above EPA’s reporting limits in 2023–2025.
Has the water system in 94503 had violations?
Health-based violations since 2016: Tthm. All are listed as resolved.
What natural hazards affect ZIP 94503?
FEMA’s National Risk Index rates the overall natural-hazard risk here as Very High; the highest-rated hazards are earthquake (very high), riverine flooding (very high), coastal flooding (relatively moderate).
Are there Superfund sites near 94503?
No active Superfund site within 10 miles of the ZIP center.
Is radon a problem in Napa County?
Napa County is in EPA radon zone 3 (low potential). Predicted average under 2 pCi/L — but any home can have high radon, so EPA still recommends a test.