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San Dimas, CA Tap Water Quality 2026

Water quality report for San Dimas, CA — PFAS, lead and copper results, violation history and state inspection findings from EPA SDWIS.

A look at San Dimas's drinking water using EPA enforcement records: violations, lead and copper results, PFAS sampling and state inspection findings.

Main Utility: Three Valleys Mwd PWSID: CA1910041 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead has not been reported for this system and no violations are open. PFAS has never been sampled at this system.

B

San Dimas earns a B for water quality

Graded on violations alone, with state inspection findings. PFAS not tested. Lead not reported.

Lead: not reported
PFAS never sampled at this system
No violations since 2015
No violations currently open
San Dimas's lead level vs. all California community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: — 0% of the federal action level
✓ Lower lead than % of California utilities
Population Served
14148
~15 connections
Water Source
Surface water
Drawn from surface water — SDWIS source code SW
Active Violations
0
None on record since 2015

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
0% of EPA action level
Action level: 15 ppb
No lead result has been reported for this system in the current window. That is a gap in state reporting, not a finding of safety.

Contaminant Violations (2015–Present)

✓ No violations on record for this water system.
Understanding violation types MCL violations mean a contaminant exceeded the federal maximum limit — the most serious type.
TT (Treatment Technique) violations mean required treatment procedures weren't followed, but don't necessarily mean contamination occurred.

Violation History

No violations are on record for this system since 2015. EPA records violations for every community water system, so this reflects a clean compliance history rather than missing data.

About the Main Water System

Utility Three Valleys Mwd
PWSID CA1910041
Water source Surface water — Drawn from surface water — SDWIS source code SW
Population served 14,148
Service connections 15
Systems serving this area 9
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is San Dimas tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open.
Does San Dimas water have PFAS? ▼
This system has never been sampled for PFAS. EPA's national monitoring covered systems serving 3,300 people or more, so no results exist — which is not evidence that none is present.
Who supplies water to San Dimas? ▼
Three Valleys Mwd (PWSID CA1910041), one of 9 systems serving this area. Surface water. Drawn from surface water — SDWIS source code SW
When was this system last inspected? ▼
It was last inspected on 2024-02-14. No significant deficiencies were recorded.

What Should San Dimas Residents Do?

1
Read your annual water report
Your supplier publishes a Consumer Confidence Report each July covering the prior year.
2
Check for a lead service line
Lead reaches tap water mainly through service lines and household plumbing. Suppliers now publish an inventory identifying lead lines.
3
Flush before drinking
If water has sat in pipes more than six hours, run the cold tap for two minutes before drinking or cooking.

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