ZipCheckup grade for 91761: C.
A mixed picture - some signals here are worth your attention.
Your top priority: use a filter certified to reduce PFAS; check which ones. Check your ZIP → EPA PFAS info
Ontario, CA (91761): PFAS Above 2029 MCL Level - 58/100
EPA data for Ontario Municipal Utilities Company
EPA records for the water systems mapped to 91761 in Ontario, CA contain zero recorded violations for inclusive record years 2021 through 2026. This does not establish that every category was monitored or published, and it does not cover events outside that source window.
Data source: U.S. Environmental Protection Agency (EPA) SDWIS
At a Glance
- Water No drinking-water violations in EPA records since 2021.
- Lead The reported 90th-percentile lead result of 0.0006 mg/L is below the EPA action level for water systems; EPA's health goal for lead is zero.
- PFAS At least one PFAS result is above an EPA MCL value (UCMR5 sampling; MCL compliance required from 2029).
- Radon EPA Zone 2 - county-level radon potential, not a home measurement.
- Flood 1 cumulative NFIP claim record. Claim evidence is historical, not current map coverage.
Get updates when new water-quality data is available for your area
Free alerts when new EPA data affects ZIP code 91761. No spam - just safety updates.
Unsubscribe anytime. We only send updates when your safety score changes. See our Privacy Policy.
See incorrect data? Let us know
Ontario (91761): one critical alert.
Score Breakdown
Overall Home Safety Score: 58/100
This is the published model score. Component and domain values are shown independently; they are not added together on this page.
Canonical components
Required domains
Coverage: 4 of 4 components and 3 of 3 domains observed.
Model 4.0.0; series home-safety-v4-cross-vertical.
Safety & Health (8) HIGH
Your Water System
ZIP code 91761 in Ontario, California is mapped to the water system Ontario Municipal Utilities Company (EPA ID: CA3610034). This system provides water to approximately 185,010 people from surface water sources.
Other Water Quality Reports in California
- 90001 (Los Angeles)
- 90002 (Los Angeles)
- 90003 (Los Angeles)
- 90004 (Los Angeles)
- 90005 (Los Angeles)
- 90006 (Los Angeles)
- 90007 (Los Angeles)
- 90008 (Los Angeles)
- 90009 (Los Angeles)
- 90010 (Los Angeles)
- 90011 (Los Angeles)
- 90012 (Los Angeles)
- 90013 (Los Angeles)
- 90014 (Los Angeles)
- 90015 (Los Angeles)
- 90016 (Los Angeles)
- 90017 (Los Angeles)
- 90018 (Los Angeles)
- 90019 (Los Angeles)
- 90020 (Los Angeles)
Nearby Water Quality Reports
- 91798 (Ontario) - 2 mi
- 91758 (Ontario) - 3 mi
- 91743 (Guasti) - 3 mi
- 91764 (Ontario) - 3 mi
- 91762 (Ontario) - 3 mi - 1 violation recorded for mapped water systems
- 91710 (Chino) - 4 mi - 5 violations recorded for mapped water systems
- 91729 (Rancho Cucamonga) - 5 mi
- 91730 (Rancho Cucamonga) - 5 mi
- 91763 (Montclair) - 5 mi
- 91708 (Chino) - 6 mi - 1 violation recorded for mapped water systems
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View available EPA compliance records for Ontario Municipal Utilities Company (CA3610034) on EPA.gov.
4 of the top compounds applied across the surrounding county in USGS pesticide-use estimates appear on EPA drinking-water monitoring lists. See the agricultural pesticide-use section.
PFAS Contamination Detected
PFAS ("forever chemicals") have been reported in samples from water systems associated with ZIP code 91761. One or more compound results are above the level of a federal PFAS MCL with compliance required from 2029.
Detected compounds: PFOA, PFHxA, PFPeA, PFBA, PFOS, PFHxS.
Highest measured level: 0.03 µg/L
Reverse osmosis (RO) and activated carbon block filters can reduce PFAS at the tap. Certifications list the compounds covered: an NSF/ANSI 53 or 58 claim for PFOA/PFOS does not cover every PFAS, so check that the product lists the compounds detected here.
Environmental Hazards (11) CRITICAL
Home & Infrastructure (6) MODERATE
Cost & Community (9) HIGH
CPSC product recall notices
These national notices are not matched to this ZIP code or water system.
Protect Your Home in Ontario
Based on local data for ZIP 91761, these services may benefit homeowners in your area.
Based on local data for your area. Use the tools below to explore your options.
Home & Flood Insurance
The ZIP code for this report in Ontario has 1 FEMA flood claim on record. Standard homeowner policies don't cover flood damage - make sure you're protected.
Typical cost: Flood insurance: premiums vary by property and flood zone; request a quote
Check Your Flood Zone (Free)FEMA flood map lookup - see if your property is in a flood zone
Free tip: Check your FEMA flood zone at msc.fema.gov (free lookup)
Gutter Installation & Repair
The median home in 91761 was built around 1986. Aging gutters can cause foundation damage, basement flooding, and mold - a professional assessment can prevent costly repairs.
Typical cost: Gutter installation: typically $1,000–$2,500 for a standard home
Estimate Your Home Maintenance CostsRoofing Inspection & Repair
Active weather alerts in California increase the risk of roof damage from hail and high winds. A professional inspection can identify vulnerabilities.
Typical cost: Roof inspection: typically $75–$300; repairs $300–$1,500
Estimate Your Home Insurance NeedsService recommendations are based on public data for this ZIP code (FEMA, Census ACS, NWS). Actual needs vary by property. By calling, your information will be shared with an independent service provider. ZipCheckup may receive compensation. Cost estimates are approximate and vary by property, condition, and contractor.
Frequently Asked Questions
Is the tap water in 91761 safe to drink?
EPA SDWIS records 0 violations since 2021 across the water systems mapped to ZIP 91761 (primary system: Ontario Municipal Utilities Company), including 0 health-based. The violation table above shows which system each record belongs to. ZipCheckup last updated this page in July 2026. The federal source release date is unavailable, so that month is not presented as source currency.
Where does 91761's water come from?
The recorded water source for Ontario Municipal Utilities Company, a system mapped to ZIP code 91761, is Surface water. This system serves approximately 185,010 people.
How does Ontario water compare to the national average?
Ontario's Home Safety Score ranks lower than 85% of U.S. ZIP codes, and lower than 95% of ZIP codes within California.
How can I get my water tested in Ontario?
If Ontario Municipal Utilities Company supplies your home, contact it for its Consumer Confidence Report; otherwise contact the water utility that serves your address, or hire a certified lab for independent home water testing. The EPA recommends annual testing if you use a private well.
Is lead a concern in 91761 tap water?
The Lead and Copper Rule record selected for 91761 reports a 90th-percentile lead result of 0.0006 mg/L for a water system mapped to this ZIP (record date 2024-12-31). The EPA action level is 0.015 mg/L. This result is below the EPA action level; it does not show the lead level in each home.
What is the radon risk for 91761?
91761 is mapped to a county in EPA Radon Zone 2 (moderate county-level radon potential; EPA recommends testing every home), located in San Bernardino County. EPA radon zones range from Zone 1 (highest county-level potential) to Zone 3 (lowest). Testing your home is recommended regardless of zone.
Are there PFAS (forever chemicals) in 91761's water?
Yes, PFAS have been detected in samples from water systems mapped to 91761. One or more PFAS results are above the level of a federal PFAS MCL with compliance required from 2029. Reverse osmosis and activated carbon filters certified to NSF/ANSI 53 or 58 specifically for PFOA/PFOS reduction can reduce PFAS.
What does the NFIP claim history show for ZIP 91761?
FEMA records contain 1 flood insurance claim filed in ZIP code 91761. Claim records do not establish current property risk. Review FEMA's map for the specific property.
How to cite this page
ZipCheckup. (2026). Ontario, CA (91761): PFAS Above 2029 MCL Level - 58/100. https://zipcheckup.com/report/91761/
@misc{zipcheckup-report-91761,
author = {{ZipCheckup}},
title = {{Ontario, CA (91761): PFAS Above 2029 MCL Level - 58/100}},
year = {2026},
url = {https://zipcheckup.com/report/91761/}
}
Page version: October 2026.
Nearby ZIP Code Reports
Water quality comparison for ZIP codes near 91761
| ZIP Code | City, State | Distance | Grade | Violations |
|---|---|---|---|---|
| 91798 | Ontario, CA | 2.0 mi | N/A | 0 |
| 91758 | Ontario, CA | 2.9 mi | N/A | 0 |
| 91743 | Guasti, CA | 3.0 mi | N/A | 0 |
| 91764 | Ontario, CA | 3.1 mi | C | 0 |
| 91762 | Ontario, CA | 3.3 mi | C | 1 |
| 91710 | Chino, CA | 4.0 mi | D | 5 |
| 91729 | Rancho Cucamonga, CA | 5.4 mi | N/A | 0 |
| 91730 | Rancho Cucamonga, CA | 5.4 mi | B | 0 |
| 91763 | Montclair, CA | 5.4 mi | C | 0 |
| 91708 | Chino, CA | 5.5 mi | N/A | 1 |
Nearby ZIP Code Reports
2026 Rankings for Your Area
Overall safety breakdown
Home Safety Score →Find the right water filter
Water Filter Matcher →Compare filters, tests & services
Compare My Options →Compare with another ZIP
Compare Tool →