A87/100
GSWC-SAN DIMAS — Water Quality Report 2026
Serving 56,538 people · California
Water Source
Purchased Surface Water
County
—
System ID
CA1910142
Violations
2
Contaminant Test Results
1 contaminant above EPA health goals
| Contaminant | Detected | Limit (MCL) | Status |
|---|---|---|---|
Lead (90th percentile) | 0.003 mg/L | 0.015 mg/L | Above Goal |
EPA Violation History
No violations in the past 5 years
Full EPA compliance since 1997.
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 GSWC-SAN DIMAS
Is GSWC-SAN DIMAS water safe to drink?
GSWC-SAN DIMAS water receives a grade of A (87/100), which is considered excellent. Out of 69 contaminants tested, none exceed EPA legal limits. 1 contaminant(s) exceed non-enforceable health goals. The water meets federal safety standards.
What contaminants has GSWC-SAN DIMAS detected?
69 contaminants were tested in GSWC-SAN DIMAS's water. Notable contaminants include Lead (90th percentile). No contaminants exceed EPA legal limits. 1 exceed EPA health goals (MCLGs).
Does GSWC-SAN DIMAS have any EPA violations?
Yes, GSWC-SAN DIMAS has 2 EPA violation(s) on record, with the most recent in 1997. Violation types include MCL. 2 are health-based violations.
How many people does GSWC-SAN DIMAS serve?
GSWC-SAN DIMAS serves approximately 56,538 people, California.
What type of water does GSWC-SAN DIMAS provide?
GSWC-SAN DIMAS 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 CA1910142.
How does GSWC-SAN DIMAS compare to other utilities in California?
GSWC-SAN DIMAS scores 87/100 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.