Public water system record

Oak Knolls Mutual Water Company

Serves Wofford Heights, Kern County, CA · 123 people served

Federal records show 6 health-based violations and 3 monitoring/reporting issues for Oak Knolls Mutual Water Company in the last ten years, including an unresolved LEAD AND COPPER RULE REVISIONS violation.

CA1500465
LAKE ISABELLA
CA
123 served

System profile

Source water Groundwater

ZIP 93240

EPA system ID CA1500465

Verify this system on EPA ECHO →

Health-based violations, last 10 years: 6
Resolved: 3
Unresolved: 1
Archived by EPA: 2
Any acute record: Yes
Monitoring issues, last 10 years: 3

Key facts

Oak Knolls Mutual Water Company draws water from 3 wells.
Highest measured level in the last 10 years: Nitrate, 23 mg/L, federal limit 10 mg/L (2.3 times the limit), 2024.
Most recent formal enforcement: compliance order (no penalty) by California, May 2024.
Record on file since 1980, with 1 health-based violation before October 19, 2016.

Check whether Oak Knolls 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
Nitrate Contaminant limit exceeded Measured 11 mg/L, federal limit 10 mg/L (1.1 times the limit)	330	Jan 1, 2025	Resolved	Yes
LEAD AND COPPER RULE REVISIONS Treatment technique failure	350	Oct 17, 2024	Active	No
Nitrate Contaminant limit exceeded Measured 13 mg/L, federal limit 10 mg/L (1.3 times the limit)	330	Oct 1, 2024	Resolved	Yes
Nitrate Contaminant limit exceeded Measured 12 mg/L, federal limit 10 mg/L (1.2 times the limit)	330	Jul 1, 2024	Resolved	Yes
Nitrate Contaminant limit exceeded Measured 23 mg/L, federal limit 10 mg/L (2.3 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.	Yes
Nitrate Contaminant limit exceeded Measured 19 mg/L, federal limit 10 mg/L (1.9 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.	Yes

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
Lead and Copper Rule Monitoring and reporting	Jul 6, 1996	Resolved
Lead and Copper Rule Monitoring and reporting	Jan 2, 1996	Resolved

Full record since 1980

EPA's records for Oak Knolls Mutual Water Company go back to 1980. Before October 19, 2016 they list 1 health-based violation (1 resolved) and 20 monitoring or reporting violations.

Violations that began in	Health-based	Monitoring and reporting
1980s	0	10
1990s	0	8
2000s	0	2
2010 to October 18, 2016	1	0
2020s	6	1

Most recent health-based violation before October 19, 2016: Total Coliform, began March 2012, Resolved.

Show the health-based violation before October 19, 2016

Contaminant	Start date	Status
Total Coliform Contaminant limit exceeded	Mar 1, 2012	Resolved

Enforcement actions

California regulators took 6 formal enforcement actions against Oak Knolls Mutual Water Company between 1994 and 2024. The most recent was a compliance order (no penalty) in May 2024.

Date	By	Action	Violations covered
May 17, 2024	California	Compliance order (no penalty)	2 violations (2 health-based): Nitrate
May 28, 2013	California	Compliance order (no penalty)	1 violation (1 health-based): Total Coliform
Mar 30, 2009	California	Compliance order (no penalty)	1 violation: Consumer Confidence Rule
Jun 10, 2008	California	Compliance order (no penalty)	1 violation: Consumer Confidence Rule
Jul 20, 2004	California	Compliance order (no penalty)	1 violation: Lead and Copper Rule
Jun 29, 1994	California	Administrative penalty	1 violation: Total Coliform

What the violations mean

Nitrate

5 incidents

Nitrate exceeded the federal limit

High nitrate is especially dangerous for infants under 6 months and can cause blue baby syndrome

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

Oak Knolls Mutual Water Company draws water from 3 wells.

Annual water quality report

Oak Knolls 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 Oak Knolls 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