OXNARD, CA · Ventura County

EL RIO MUTUAL WATER COMPANY Water System

Inactive system

This water system is marked inactive in EPA’s federal records as of February 1, 2003. It is no longer an operating public water system under this PWSID, and no compliance deadlines — including the 2027 Consumer Confidence Report rule — apply to it.

If you are a resident looking for your current water provider, see water systems in Ventura County, CA.

Data sourced from the EPA ECHO database (SDWA bulk download), last refreshed August 1, 2026. This is a record-keeping and public-information tool — it does not replace California’s official records. Always confirm current status with California before making decisions based on this information.

System facts

System ID (PWSID): CA5602106
System type: Community Water System
Population served: 400
Service connections: 100
Ownership: not on record
Water source: groundwater (wells)

EL RIO MUTUAL WATER COMPANY is one of 3,951 community water systems in California in the 500 or fewer people size category, formerly serving 400 people from groundwater.

EPA's federal records list this system as inactive in 2003; the record below is historical.

As of August 1, 2026, its federal record holds 19 entries between 1980 and 1986, all of which EPA lists as closed. Nothing has been added since 1986.

Of the 19, 2 are monitoring and reporting requirements — the category that accounts for about four in five of all violations in EPA's national dataset — rather than findings about the water itself. The record involves inorganic chemicals and the Radionuclides and Revised Rad Rule.

Violation history

Maximum Contaminant Level Violation, Single Sample
Health-based
Selenium
March 20, 1986 – March 19, 1987
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
March 20, 1986 – March 19, 1987
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
February 21, 1986 – February 20, 1987
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
January 16, 1986 – January 15, 1987
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
December 18, 1985 – December 17, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Selenium
September 17, 1985 – September 16, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
September 17, 1985 – September 16, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Selenium
September 10, 1985 – September 9, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
September 10, 1985 – September 9, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Selenium
August 12, 1985 – August 11, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
August 12, 1985 – August 11, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Selenium
July 18, 1985 – July 17, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
July 18, 1985 – July 17, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
June 11, 1985 – June 10, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Selenium
May 8, 1985 – May 7, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
May 8, 1985 – May 7, 1986
Archived
Maximum Contaminant Level Violation, Single Sample
Health-based
Nitrate
April 10, 1985 – April 9, 1986
Archived
Monitoring, Regular
—
Gross Alpha, Excl. Radon and U
October 1, 1981 – September 30, 1982
Archived
Monitoring, Regular
—
Gross Alpha, Excl. Radon and U
October 30, 1980 – October 29, 1981
Archived

Archived closed in EPA's records (typically due to age or a data correction)

Period	Violation	Contaminant / rule	Health-based	Status
March 20, 1986 – March 19, 1987	Maximum Contaminant Level Violation, Single Sample	Selenium	Health-based	Archived
March 20, 1986 – March 19, 1987	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
February 21, 1986 – February 20, 1987	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
January 16, 1986 – January 15, 1987	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
December 18, 1985 – December 17, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
September 17, 1985 – September 16, 1986	Maximum Contaminant Level Violation, Single Sample	Selenium	Health-based	Archived
September 17, 1985 – September 16, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
September 10, 1985 – September 9, 1986	Maximum Contaminant Level Violation, Single Sample	Selenium	Health-based	Archived
September 10, 1985 – September 9, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
August 12, 1985 – August 11, 1986	Maximum Contaminant Level Violation, Single Sample	Selenium	Health-based	Archived
August 12, 1985 – August 11, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
July 18, 1985 – July 17, 1986	Maximum Contaminant Level Violation, Single Sample	Selenium	Health-based	Archived
July 18, 1985 – July 17, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
June 11, 1985 – June 10, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
May 8, 1985 – May 7, 1986	Maximum Contaminant Level Violation, Single Sample	Selenium	Health-based	Archived
May 8, 1985 – May 7, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
April 10, 1985 – April 9, 1986	Maximum Contaminant Level Violation, Single Sample	Nitrate	Health-based	Archived
October 1, 1981 – September 30, 1982	Monitoring, Regular	Gross Alpha, Excl. Radon and U	—	Archived
October 30, 1980 – October 29, 1981	Monitoring, Regular	Gross Alpha, Excl. Radon and U	—	Archived

Archived closed in EPA's records (typically due to age or a data correction)

Enforcement actions

No enforcement actions on record for this system.

Last known contact on file (system is inactive)

Not on record

Phone not on record

OXNARD, CA 93030