States ›California ›San Luis Obispo County ›Oak Shores

Oak Shores, CA Tap Water Quality 2026

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

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

Main Utility: Nacimiento Water Company PWSID: CA4010027 Updated: 2026 Q2
✅

No federal limits exceeded on record

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

B

Oak Shores earns a B for water quality

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

Lead: not detected
PFAS never sampled at this system
39 violations since 2015, 26 health-based
No violations currently open
Oak Shores's lead level vs. all California community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: Not detected — 0% of the federal action level
✓ Lower lead than % of California utilities
Population Served
119
~663 connections
Water Source
Surface water
Drawn from surface water — SDWIS source code SW
Active Violations
0
39 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
0% of EPA action level
Not detected
Action level: 15 ppb
Lead was not detected at the 90th percentile — the result fell below the laboratory detection limit. That is not the same as an absence of lead in every tap, and older homes with lead service lines can still show higher readings.

Contaminant Violations (2015–Present)

ContaminantTypeMeasuredLimitPeriodStatus
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.66 MG/L 0.060 mg/L 2024 Archived
Consumer Confidence Rule OTHER — — 2024 Addressed
Lead and Copper Rule MONITORING AND REPORTING — TT 2023 Resolved
TTHM MONITORING AND REPORTING — 0.080 mg/L 2023 Resolved
Total Haloacetic Acids (HAA5) MONITORING AND REPORTING — 0.060 mg/L 2023 Resolved
TTHM MCL EXCEEDANCE 0.1 MG/L 0.080 mg/L 2023 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.102 MG/L 0.060 mg/L 2023 Resolved
TTHM MCL EXCEEDANCE 0.105 MG/L 0.080 mg/L 2023 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.102 MG/L 0.060 mg/L 2023 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2023 Addressed
TTHM MCL EXCEEDANCE 0.083 MG/L 0.080 mg/L 2022 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.083 MG/L 0.060 mg/L 2022 Resolved
TTHM MCL EXCEEDANCE 0.091 MG/L 0.080 mg/L 2022 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.072 MG/L 0.060 mg/L 2022 Resolved
Bromate MONITORING AND REPORTING — 0.010 mg/L 2020 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.07 MG/L 0.060 mg/L 2020 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.08 MG/L 0.060 mg/L 2019 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.079 MG/L 0.060 mg/L 2019 Resolved
TTHM MONITORING AND REPORTING — 0.080 mg/L 2019 Resolved
Total Haloacetic Acids (HAA5) MONITORING AND REPORTING — 0.060 mg/L 2019 Resolved
Bromate MONITORING AND REPORTING — 0.010 mg/L 2019 Resolved
TTHM MCL EXCEEDANCE 0.081 MG/L 0.080 mg/L 2019 Resolved
TTHM MCL EXCEEDANCE 0.084 MG/L 0.080 mg/L 2019 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.085 MG/L 0.060 mg/L 2019 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.086 MG/L 0.060 mg/L 2019 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.063 MG/L 0.060 mg/L 2018 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.083 MG/L 0.060 mg/L 2018 Resolved
Bromate MONITORING AND REPORTING — 0.010 mg/L 2018 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.107 MG/L 0.060 mg/L 2018 Resolved
TTHM MONITORING AND REPORTING — 0.080 mg/L 2018 Resolved
Total Haloacetic Acids (HAA5) MONITORING AND REPORTING — 0.060 mg/L 2018 Resolved
Bromate MONITORING AND REPORTING — 0.010 mg/L 2018 Resolved
TTHM MCL EXCEEDANCE 0.087 MG/L 0.080 mg/L 2017 Resolved
TTHM MCL EXCEEDANCE 0.092 MG/L 0.080 mg/L 2016 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.073 MG/L 0.060 mg/L 2016 Resolved
TTHM MCL EXCEEDANCE 0.099 MG/L 0.080 mg/L 2016 Resolved
TTHM MCL EXCEEDANCE 0.088 MG/L 0.080 mg/L 2016 Resolved
TTHM MCL EXCEEDANCE 0.084 MG/L 0.080 mg/L 2016 Resolved
Total Haloacetic Acids (HAA5) MCL EXCEEDANCE 0.066 MG/L 0.060 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

39 violations are on record since 2015, of which 26 were health-based. All have been resolved and none remain open.

About the Main Water System

Utility Nacimiento Water Company
PWSID CA4010027
Water source Surface water — Drawn from surface water — SDWIS source code SW
Population served 119
Service connections 663
Systems serving this area 1
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Oak Shores tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open.
Does Oak Shores 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 Oak Shores? ▼
Nacimiento Water Company (PWSID CA4010027). Surface water. Drawn from surface water — SDWIS source code SW
When was this system last inspected? ▼
It was last inspected on 2023-04-06. No significant deficiencies were recorded.

What Should Oak Shores 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.

Nearby Cities in California

San Luis Obispo, Ca Tap Water Quality 2026 San Luis Obispo El Paso de Robles (Paso Robles), Ca Tap Water Quality 2026 San Luis Obispo Atascadero, Ca Tap Water Quality 2026 San Luis Obispo Arroyo Grande, Ca Tap Water Quality 2026 San Luis Obispo Grover Beach, Ca Tap Water Quality 2026 San Luis Obispo Nipomo, Ca Tap Water Quality 2026 San Luis Obispo