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Grimes, CA Tap Water Quality 2026

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

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

Main Utility: Colusa Co. Wwd #1 - Grimes PWSID: CA0600008 Updated: 2026 Q2
✅

No federal limits exceeded on record

Lead is 5.77 ppb, 38% of the action level and no violations are open. PFAS has never been sampled at this system.

B

Grimes earns a B for water quality

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

Lead: 5.77 ppb — 38% of the federal action level
PFAS never sampled at this system
47 violations since 2015, 39 health-based
No violations currently open
Grimes's lead level vs. all California community water systems
0 ppb5 ppb10 ppb15 ppb
Lead level: 5.77 ppb — 38% of the federal action level
✓ Lower lead than 13% of California utilities
Population Served
294
~114 connections
Water Source
Groundwater
Drawn from wells — SDWIS source code GW
Active Violations
0
47 since 2015, all resolved

Lead & Copper Testing

Lead (Pb)
90th percentile of tap samples collected across the distribution system
38% of EPA action level
5.77 ppb
Action level: 15 ppb
The 90th-percentile lead result is 5.77 ppb, 38% 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
Lead and Copper Rule MONITORING AND REPORTING — TT 2025 Unaddressed
Arsenic MCL EXCEEDANCE 23.5 UG/L 0.010 mg/L 2024 Archived
Arsenic MCL EXCEEDANCE 23.6 UG/L 0.010 mg/L 2024 Archived
Arsenic MCL EXCEEDANCE 22.4 UG/L 0.010 mg/L 2024 Archived
Arsenic MCL EXCEEDANCE 22.9 UG/L 0.010 mg/L 2024 Archived
Lead and Copper Rule MONITORING AND REPORTING — TT 2023 Resolved
Arsenic MCL EXCEEDANCE 22.9 UG/L 0.010 mg/L 2023 Archived
Arsenic MCL EXCEEDANCE 25.3 UG/L 0.010 mg/L 2023 Archived
Arsenic MCL EXCEEDANCE 25.9 UG/L 0.010 mg/L 2023 Archived
Arsenic MCL EXCEEDANCE 26.5 UG/L 0.010 mg/L 2023 Archived
Revised Total Coliform Rule MONITORING FAILURE — — 2022 Resolved
Arsenic MCL EXCEEDANCE 26.2 UG/L 0.010 mg/L 2022 Archived
Arsenic MCL EXCEEDANCE 25.4 UG/L 0.010 mg/L 2022 Archived
Arsenic MCL EXCEEDANCE 25 UG/L 0.010 mg/L 2022 Archived
Arsenic MCL EXCEEDANCE 22.7 UG/L 0.010 mg/L 2022 Archived
Revised Total Coliform Rule MONITORING FAILURE — — 2021 Resolved
Arsenic MCL EXCEEDANCE 23.8 UG/L 0.010 mg/L 2021 Archived
Arsenic MCL EXCEEDANCE 24.9 UG/L 0.010 mg/L 2021 Archived
Arsenic MCL EXCEEDANCE 23.6 UG/L 0.010 mg/L 2021 Archived
Arsenic MCL EXCEEDANCE 24.6 UG/L 0.010 mg/L 2021 Archived
Revised Total Coliform Rule MONITORING FAILURE — — 2020 Resolved
Arsenic MCL EXCEEDANCE 22.8 UG/L 0.010 mg/L 2020 Archived
Arsenic MCL EXCEEDANCE 23.5 UG/L 0.010 mg/L 2020 Archived
Arsenic MCL EXCEEDANCE 24.1 UG/L 0.010 mg/L 2020 Archived
Arsenic MCL EXCEEDANCE 22.2 UG/L 0.010 mg/L 2020 Archived
Arsenic MCL EXCEEDANCE 22.7 UG/L 0.010 mg/L 2019 Archived
Arsenic MCL EXCEEDANCE 23.5 UG/L 0.010 mg/L 2019 Archived
Arsenic MCL EXCEEDANCE 23 UG/L 0.010 mg/L 2019 Archived
Arsenic MCL EXCEEDANCE 20.8 UG/L 0.010 mg/L 2019 Archived
Arsenic MCL EXCEEDANCE 20.4 UG/L 0.010 mg/L 2018 Archived
Arsenic MCL EXCEEDANCE 23.9 UG/L 0.010 mg/L 2018 Archived
Arsenic MCL EXCEEDANCE 25.1 UG/L 0.010 mg/L 2018 Archived
Arsenic MCL EXCEEDANCE 23 UG/L 0.010 mg/L 2018 Archived
Lead and Copper Rule MONITORING AND REPORTING — TT 2017 Resolved
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2017 Archived
Arsenic MCL EXCEEDANCE 26 UG/L 0.010 mg/L 2017 Archived
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2017 Archived
Nitrate MONITORING AND REPORTING — 10 mg/L 2017 Resolved
Arsenic MCL EXCEEDANCE 25 UG/L 0.010 mg/L 2017 Archived
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2016 Archived
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2016 Archived
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2016 Archived
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2016 Archived
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2015 Resolved
Lead and Copper Rule MONITORING AND REPORTING — TT 2015 Resolved
Arsenic MCL EXCEEDANCE 24 UG/L 0.010 mg/L 2015 Resolved
Arsenic MCL EXCEEDANCE 23.8 UG/L 0.010 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

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

About the Main Water System

Utility Colusa Co. Wwd #1 - Grimes
PWSID CA0600008
Water source Groundwater — Drawn from wells — SDWIS source code GW
Population served 294
Service connections 114
Systems serving this area 1
Regulator State primacy agency
Data through 2026 Q2 — EPA SDWIS

Frequently Asked Questions

Is Grimes tap water safe to drink? ▼
No federal limit is exceeded on record. No violations are currently open. Lead is 5.77 ppb, 38% of the action level.
Does Grimes 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 Grimes? ▼
Colusa Co. Wwd #1 - Grimes (PWSID CA0600008). Groundwater. Drawn from wells — SDWIS source code GW
When was this system last inspected? ▼
It was last inspected on 2025-07-22. No significant deficiencies were recorded.

What Should Grimes Residents Do?

1
Consider a filter certified for lead
Look for NSF/ANSI 53 certification for lead reduction.
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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