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Oakley, CA Tap Water Quality 2026

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

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

Main Utility: Diablo Water District PWSID: CA0710007 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 1.90 ppb, 13% of the action level and no violations are open. PFAS was sampled but not enough times for a compliance determination.

B

Oakley earns a B for water quality

Graded on violations and lead, with state inspection findings. PFAS not tested.

Lead: 1.90 ppb — 13% of the federal action level
PFAS sampled, too few results to judge
No violations since 2015
No violations currently open
Oakley's lead level vs. all California community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 1.90 ppb — 13% of the federal action level
✓ Lower lead than 61% of California utilities
Population Served
21603
~13617 connections
Water Source
Surface water
Purchased from another system — SDWIS source code SWP
Active Violations
0
None on record since 2015

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
13% of EPA action level
1.90 ppb
Action level: 15 ppb
The 90th-percentile lead result is 1.90 ppb, 13% 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)

✓ 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 Diablo Water District
PWSID CA0710007
Water source Surface water — Purchased from another system — SDWIS source code SWP
Population served 21,603
Service connections 13,617
Systems serving this area 10
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Oakley tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 1.90 ppb, 13% of the action level.
Does Oakley water have PFAS? ▼
It was sampled, but no sampling point had enough results for a compliance determination.
Who supplies water to Oakley? ▼
Diablo Water District (PWSID CA0710007), one of 10 systems serving this area. Surface water. Purchased from another system — SDWIS source code SWP
When was this system last inspected? ▼
It was last inspected on 2024-01-30. No significant deficiencies were recorded.

What Should Oakley 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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