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June 13, 2024 6:42PM
June 13, 2024 18:42PM

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TCE - El Toro Facts



IRWD continuously monitors the quality of water from its drinking sources. We regularly test our 18 drinking water wells located in Santa Ana, and have never detected TCE in drinking water served to its customers. There are no drinking water wells located in the TCE plume emanating from the former El Toro Marine Corps Air Station. Further, in March 2009 the U.S. EPA determined no "potential vapor intrusion problems" exist in Irvine neighborhoods.


In 1985 trichloroethylene, also known as TCE, was found in portions of the groundwater basin beneath the former El Toro Marine Corps Air Station and central Irvine. TCE is a volatile organic compound, or VOC, that was widely used as a solvent for aircraft cleaning. Prior to the development of stricter environmental regulations in the mid-1970’s, it was common to dispose of cleaning solvents by simply rinsing off the aircraft and allowing the runoff to run into the ground. As a result of these past disposal practices, a one-by-three mile plume of contamination now extends off the base (see maps in Important Links below). The contamination is about 150 feet deep beneath the base and 300-700 feet deep in the community area. 

 Irvine's Drinking Water Is Safe

Drinking water in Irvine has been and continues to be absolutely safe. IRWD’s drinking water meets or exceeds all state and federal water quality requirements. IRWD maintains a state-certified water quality laboratory that performs more than a quarter of a million tests annually on our water supply to ensure that high quality water is monitored and maintained. The plume is several miles from IRWD’s drinking water well field and therefore does not affect IRWD’s drinking water supply.

 Cleaning Up The Groundwater

IRWD, the Orange County Water District and the United States Department of the Navy have completed a joint project, the El Toro Groundwater Remediation Project, which is designed to clean up the TCE plume. This project began full operation in January 2007 and pumps water from the plume of TCE contamination. Following treatment to remove the TCE, this water is used only for non-drinking purposes. Each year the El Toro Groundwater Remediation Project provides 1.3 billion gallons of clean water for non-drinking water purposes, which is enough to irrigate 1,300 acres of landscaping. The clean-up of the plume is expected to take approximately 40 years.

 For More Information

Jim Colston
Director of Water Quality and Regulatory Compliance 
Irvine Ranch Water District

Roy Herndon
Chief Hydrogeologist
Orange County Water District

Elizabeth Roddy
BRAC Environmental Coordinator
Former MCAS El Toro and Tustin 

 Important Links