F19/100
MODESTO, CITY OF — Water Quality Report 2026
Serving 218,771 people · California
Water Source
Purchased Surface Water
County
—
System ID
CA5010010
Violations
14
Contaminant Test Results
3 contaminants above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
PFOS | 0.005 µg/L | 0.004 µg/L | Over Limit |
PFOA | 0.004 µg/L | 0.004 µg/L | Over Limit |
chlorate | 960.00 µg/L | — | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 2013.
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 MODESTO, CITY OF
Is MODESTO, CITY OF water safe to drink?
MODESTO, CITY OF water receives a grade of F (19/100), which is considered failing. 2 contaminant(s) exceed EPA legal limits and 14 violation(s) are on record. Customers may want to consider using a water filter.
What contaminants has MODESTO, CITY OF detected?
76 contaminants were tested in MODESTO, CITY OF's water. Notable contaminants include PFOS, PFOA, chlorate. 2 exceed EPA legal limits (MCLs). 3 exceed EPA health goals (MCLGs).
Does MODESTO, CITY OF have any EPA violations?
Yes, MODESTO, CITY OF has 14 EPA violation(s) on record, with the most recent in 2013. Violation types include MCL, MR. 12 are health-based violations.
How many people does MODESTO, CITY OF serve?
MODESTO, CITY OF serves approximately 218,771 people, California. The system provides water to 1 community: Modesto.
What type of water does MODESTO, CITY OF provide?
MODESTO, 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 CA5010010.
How does MODESTO, CITY OF compare to other utilities in California?
MODESTO, CITY OF scores 19/100 with a grade of F (failing). This score suggests significant water quality concerns relative to other utilities. Visit our California state page for a full comparison of water systems.