A92/100
ONTARIO MUNICIPAL UTILITIES COMPANY — Water Quality Report 2026
Serving 185,010 people · California
Water Source
Purchased Surface Water
County
—
System ID
CA3610034
Violations
1
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | < 0.001 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 1993.
Understanding violation severity
Tier 1Urgent health risk. Utility must notify all customers within 24 hours.Tier 2Important health or treatment issue. Customers notified within 30 days.Tier 3Administrative or monitoring issue. Reported in the annual water quality report.
Source: EPA Safe Drinking Water Information System (SDWIS) · Updated quarterly
Frequently Asked Questions About ONTARIO MUNICIPAL UTILITIES COMPANY
Is ONTARIO MUNICIPAL UTILITIES COMPANY water safe to drink?
ONTARIO MUNICIPAL UTILITIES COMPANY water receives a grade of A (92/100), which is considered excellent. Out of 76 contaminants tested, none exceed EPA legal limits. 1 contaminant(s) exceed non-enforceable health goals. The water meets federal safety standards.
What contaminants has ONTARIO MUNICIPAL UTILITIES COMPANY detected?
76 contaminants were tested in ONTARIO MUNICIPAL UTILITIES COMPANY's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does ONTARIO MUNICIPAL UTILITIES COMPANY have any EPA violations?
Yes, ONTARIO MUNICIPAL UTILITIES COMPANY has 1 EPA violation(s) on record, with the most recent in 1993. Violation types include TT. 1 are health-based violations.
How many people does ONTARIO MUNICIPAL UTILITIES COMPANY serve?
ONTARIO MUNICIPAL UTILITIES COMPANY serves approximately 185,010 people, California. The system provides water to 1 community: Ontario.
What type of water does ONTARIO MUNICIPAL UTILITIES COMPANY provide?
ONTARIO MUNICIPAL UTILITIES COMPANY sources its water from purchased surface water. Surface water comes from rivers, lakes, or reservoirs and typically requires more extensive treatment. The utility's system ID is CA3610034.
How does ONTARIO MUNICIPAL UTILITIES COMPANY compare to other utilities in California?
ONTARIO MUNICIPAL UTILITIES COMPANY scores 92/100 with a grade of A (excellent). This places it among the higher-performing utilities in the state. Visit our California state page for a full comparison of water systems.