Public water system record

Oakley Mutual Water Company

Serves an area of Contra Costa County, CA · 170 people served

Federal records show 18 health-based violations and 1 monitoring/reporting issue for Oakley Mutual Water Company in the last ten years, including an unresolved LEAD AND COPPER RULE REVISIONS violation.

CA0706004
OAKLEY
CA
170 served

System profile

Source water Groundwater

ZIP 94561

EPA system ID CA0706004

Verify this system on EPA ECHO →

Health-based violations, last 10 years: 18
Resolved: 0
Unresolved: 1
Archived by EPA: 17
Any acute record: No
Monitoring issues, last 10 years: 1

Key facts

Oakley Mutual Water Company draws water from 1 well.
Highest measured level in the last 10 years: Arsenic, 0.015 mg/L, federal limit 0.01 mg/L (1.5 times the limit), 2021.
Most recent formal enforcement: compliance order (no penalty) by California, December 2021.
Record on file since 2008, with 0 health-based violations before October 19, 2016.

Check whether Oakley Mutual Water Company serves your address

Health-based violations

Since October 2016

Violation data reflects EPA records through March 2026. For the most current status, visit the EPA ECHO database.

Contaminant	Rule family	Start date	Status	Acute
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Oct 1, 2025	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.014 mg/L, federal limit 0.01 mg/L (1.4 times the limit)	330	Jul 1, 2025	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Apr 1, 2025	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Jan 1, 2025	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
LEAD AND COPPER RULE REVISIONS Treatment technique failure	350	Oct 17, 2024	Active	No
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Oct 1, 2024	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Jul 1, 2024	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.012 mg/L, federal limit 0.01 mg/L (1.2 times the limit)	330	Apr 1, 2024	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Jan 1, 2024	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.012 mg/L, federal limit 0.01 mg/L (1.2 times the limit)	330	Oct 1, 2023	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.012 mg/L, federal limit 0.01 mg/L (1.2 times the limit)	330	Jul 1, 2023	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Apr 1, 2023	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.013 mg/L, federal limit 0.01 mg/L (1.3 times the limit)	330	Jan 1, 2023	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.014 mg/L, federal limit 0.01 mg/L (1.4 times the limit)	330	Oct 1, 2022	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.012 mg/L, federal limit 0.01 mg/L (1.2 times the limit)	330	Jul 1, 2022	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.012 mg/L, federal limit 0.01 mg/L (1.2 times the limit)	330	Apr 1, 2022	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.014 mg/L, federal limit 0.01 mg/L (1.4 times the limit)	330	Jan 1, 2022	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No
Arsenic Contaminant limit exceeded Measured 0.015 mg/L, federal limit 0.01 mg/L (1.5 times the limit)	330	Oct 1, 2021	Archived Violation period ended. EPA no longer counts it toward current compliance, but no fix was formally recorded.	No

Monitoring and reporting issues

Since October 2016

Missed tests or reports, not contaminants found above a limit.

Issue	Start date	Status
LEAD AND COPPER RULE REVISIONS RPT	Oct 17, 2024	Active

Full record since 2008

EPA's records for Oakley Mutual Water Company go back to 2008. Before October 19, 2016 they list no health-based violations and 2 monitoring or reporting violations.

Violations that began in	Health-based	Monitoring and reporting
2000s	0	1
2010 to October 18, 2016	0	1
2020s	18	1

Enforcement actions

California regulators took 1 formal enforcement action against Oakley Mutual Water Company in 2021. The most recent was a compliance order (no penalty) in December 2021.

Date	By	Action	Violations covered
Dec 10, 2021	California	Compliance order (no penalty)	17 violations (17 health-based): Arsenic

What the violations mean

Arsenic

17 incidents

Arsenic exceeded the federal limit

Long-term arsenic exposure is linked to cancer and cardiovascular effects

LEAD AND COPPER RULE REVISIONS

1 incident

The system did not complete a treatment step or action that the LEAD AND COPPER RULE REVISIONS requires (a treatment technique violation).

The utility had to notify customers about this violation.

Where the water comes from

Oakley Mutual Water Company draws water from 1 well.

Annual water quality report

Oakley Mutual Water Company must give its customers an annual water quality report (Consumer Confidence Report) by July 1, with the levels its tests found in the previous year.

Systems serving 500 or fewer people may meet the rule by telling customers the report is available on request, so you may need to ask Oakley Mutual Water Company for a copy.

Find a posted report with EPA's Consumer Confidence Report search

Testing your own water

To test the water at your tap, or a private well this record does not cover, use a laboratory certified for drinking water by California.

Certified drinking water labs by state EPA guidance for private wells