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Water Quality

Surface Water
The City of Irvine is mandated by a federal National Pollutant Discharge Elimination System (NPDES) permit to implement Storm Water Runoff Management Programs.  Unlike the sanitary sewer system, any discharge to the municipal storm drain system does not get treated and will ultimately end up in the ocean.  The Storm Water Runoff Management Programs are designed to protect the water quality and beneficial uses of the receiving water body. For more information on the City's stormwater management activities and requirements for new development and significant redevelopment, visit our Environmental Programs web page at cityofirvine.org/environmentalprograms.


Drinking Water Safety
Irvine’s drinking water is safe. It comes from the Irvine Ranch Water District (IRWD) and meets, or is of higher quality than, all state and federal water quality regulations. California’s drinking water standards are among the most stringent in the nation and in many cases are more demanding, and therefore supersede, federal requirements.IRWD maintains a state-certified water quality laboratory that annually performs over a quarter of a million tests on your water supplies to ensure high quality. All IRWD customers receive a printed water quality report each year by July 1. To request a copy of the latest water quality report, simply call IRWD at (949) 453-5500 or visit www.irwd.com to view the report online.

Water Sources
Approximately 35 percent of Irvine’s drinking water is purchased from the Metropolitan Water District of Southern California (MWD). This imported water comes from the Colorado River via the Colorado River Aqueduct and from Northern California via the State Water Project.The remaining 65 percent of Irvine’s drinking water supply comes from IRWD’s local groundwater wells in the Orange County Groundwater Basin, managed by the Orange County Water District (OCWD). These wells range in depth from 400 to 2,000 feet and extract high quality water.The blend of imported and groundwater vary according to the time of year and the customer’s geographical location within the District.

Irvine Desalter Project
IRWD, OCWD and the Department of the Navy designed a joint program, to clean up a deep underground plume of trichloroethylene (TCE) pollution coming from the former El Toro Marine Base. TCE is a chemical contained in solvents used to clean airplane engine parts. The pollution resulted from past disposal and waste management practices on the Base that were common before the development of stricter environmental regulations in the 1970s.

Water from the polluted area is pumped from wells on the former base and in the community and piped to two purification plants to remove the contaminants.The cleaned water is used only for irrigation and other non-drinking water uses.The Irvine Desalter Project provides the solution to the contamination problem, and is not the cause.

IRWD’s wells are monitored annually for TCE by OCWD. In addition, IRWD monitors its aggregate supply of well water more frequently. All of these test results are reported directly to the California Department of Health Services, the agency that regulates drinking water. The drinking water in Irvine meets all federal and state health standards and is safe to drink.

Further Information

Click here to visit our new Environmental Programs website!