Home hazard report for 91761 — Ontario, CA
ZIP 91761 is served by Ontario Municipal Utilities Company: no health-based violations since 2016, latest lead result 0.6 ppb, PFAS 30 ppt. San Bernardino County is in EPA radon zone 2.
No health-based violations reported since 2016.
90th-percentile lead in the latest round (Jan 2022). Lead comes mostly from household plumbing and service lines, so individual homes can be higher.
Highest PFOA or PFOS result in EPA’s 2023–2025 testing was at or above 4.0 ppt, EPA’s 2024 maximum contaminant level for each. 6 PFAS compounds detected.
Predicted average indoor radon between 2 and 4 pCi/L. Test your home; many homes here exceed 4 pCi/L.
FEMA’s overall natural-hazard risk for this census tract, relative to the rest of the U.S.
The nearest active Superfund site is 7.7 miles away.
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Where ZIP 91761 is
Dashed: ZIP area · blue: utility service area · scroll or pinch to zoomDrinking water: Ontario Municipal Utilities Company
Health-based violations
No health-based violations reported since 2016.
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 |
|---|---|---|---|
| PFOA | 30 ppt | 1 of 36 | 4 ppt MCL |
| PFHxA | 7.1 ppt | 1 of 36 | — |
| PFPeA | 6.7 ppt | 2 of 36 | — |
| PFBA | 6.4 ppt | 2 of 36 | — |
| PFOS | 5.2 ppt | 1 of 36 | 4 ppt MCL |
| PFHxS | 4.2 ppt | 1 of 36 | — |
| PFBS | not detected | 0 of 36 | — |
| PFDA | not detected | 0 of 36 | — |
| PFHpA | not detected | 0 of 36 | — |
| PFNA | not detected | 0 of 36 | — |
| HFPO-DA (GenX) | not detected | 0 of 36 | — |
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 San Bernardino County
EPA radon zone 2 — moderate potential. Predicted average indoor radon between 2 and 4 pCi/L. Test your home; many homes here exceed 4 pCi/L.
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 Relatively High, with very low social vulnerability and very low 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
| Site | Status | Distance |
|---|---|---|
| Stringfellow Glen Avon Heights, California · EPA ID CAT080012826 | Active (final NPL) | 7.7 mi |
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 91761
Who supplies drinking water to ZIP 91761?
Ontario Municipal Utilities Company (EPA ID CA3610034), a surface water (rivers, lakes) system serving about 185,010 people.
Is there lead in Ontario, CA tap water?
The utility’s latest 90th-percentile lead result (Jan 2022) was 0.6 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 Ontario, CA water have PFAS?
Highest PFOA or PFOS result in EPA’s 2023–2025 testing was at or above 4.0 ppt, EPA’s 2024 maximum contaminant level for each. 6 PFAS compounds detected.
Has the water system in 91761 had violations?
No health-based violations reported since 2016.
What natural hazards affect ZIP 91761?
FEMA’s National Risk Index rates the overall natural-hazard risk here as Relatively High; the highest-rated hazards are riverine flooding (very high), earthquake (relatively moderate), heat wave (relatively low).
Are there Superfund sites near 91761?
The nearest active Superfund site is 7.7 miles away. Sites within 10 miles: Stringfellow (7.7 mi, Active (final NPL)).
Is radon a problem in San Bernardino County?
San Bernardino County is in EPA radon zone 2 (moderate potential). Predicted average indoor radon between 2 and 4 pCi/L. Test your home; many homes here exceed 4 pCi/L.