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Clearlake, CA Tap Water Quality 2026

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

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

Main Utility: Highlands Mutual Water Company PWSID: CA1710003 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 4.60 ppb, 31% of the action level and no violations are open. No PFAS was detected.

B

Clearlake earns a B for water quality

Graded on violations, lead, and PFAS, with state inspection findings.

Lead: 4.60 ppb — 31% of the federal action level
PFAS tested, none detected
6 violations since 2015, 5 health-based
No violations currently open
Clearlake's lead level vs. all California community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 4.60 ppb — 31% of the federal action level
✓ Lower lead than 20% of California utilities
Population Served
6914
~2355 connections
Water Source
Surface water
Drawn from surface water — SDWIS source code SW
Active Violations
0
6 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
31% of EPA action level
4.60 ppb
Action level: 15 ppb
The 90th-percentile lead result is 4.60 ppb, 31% of the 15 ppb federal action level. The action level is a treatment trigger, not a legal maximum, and it is measured across sampled taps rather than at any single home.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 61.125 MG/L 0.060 mg/L 2021 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.064 MG/L 0.060 mg/L 2021 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2019 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 61.4 UG/L 0.060 mg/L 2019 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 61 UG/L 0.060 mg/L 2019 Resolved
TTHM MCL EXCEEDANCE 81.7 UG/L 0.080 mg/L 2015 Resolved
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

6 violations are on record since 2015, of which 5 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Highlands Mutual Water Company
PWSID CA1710003
Water source Surface water — Drawn from surface water — SDWIS source code SW
Population served 6,914
Service connections 2,355
Systems serving this area 4
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Clearlake tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 4.60 ppb, 31% of the action level.
Does Clearlake water have PFAS? ▼
It was tested for the six regulated PFAS compounds and none were detected.
Who supplies water to Clearlake? ▼
Highlands Mutual Water Company (PWSID CA1710003), one of 4 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 2019-05-13. No significant deficiencies were recorded.

What Should Clearlake 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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