D21/100
CORONA, CITY OF — Water Quality Report 2026
Serving 168,575 people · California
Water Source
Purchased Surface Water
County
—
System ID
CA3310037
Violations
21
Contaminant Test Results
3 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Copper (90th percentile) | 1.77 mg/L | 1.30 mg/L | Over Limit |
chlorate | 360.00 µg/L | — | Above Goal |
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
2
Violations (last 5yr)
0
Unresolved
0
Health-Related
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: April 1, 2022 – June 30, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issued
TIER 3Resolved
Failed Level 2 Assessment under Revised Total Coliform Rule
This is a paperwork/process violation — it does not mean a contaminant was detected at unsafe levels.
When: April 1, 2022 – June 30, 2022Rule: Stage 2 DBPREnforcement: Formal — state order issued
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 CORONA, CITY OF
Is CORONA, CITY OF water safe to drink?
CORONA, CITY OF water receives a grade of D (21/100), which is considered poor. 1 contaminant(s) exceed EPA legal limits and 21 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has CORONA, CITY OF detected?
77 contaminants were tested in CORONA, CITY OF's water. Notable contaminants include Copper (90th percentile), Lead (90th percentile), chlorate. 1 exceed EPA legal limits (MCLs). 3 exceed EPA health goals (MCLGs).
Does CORONA, CITY OF have any EPA violations?
Yes, CORONA, CITY OF has 21 EPA violation(s) on record, with the most recent in 2022. Violation types include MR, Other, MCL. 11 are health-based violations.
How many people does CORONA, CITY OF serve?
CORONA, CITY OF serves approximately 168,575 people, California. The system provides water to 1 community: Corona.
What type of water does CORONA, CITY OF provide?
CORONA, CITY OF 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 CA3310037.
How does CORONA, CITY OF compare to other utilities in California?
CORONA, CITY OF scores 21/100 with a grade of D (poor). This score suggests significant water quality concerns relative to other utilities. Visit our California state page for a full comparison of water systems.