• Water Quality
• Water Supply
• Wastewater
• Recycled Water
• Backflow Prevention
• Urban Runoff
• Facilities
• Urban Water Management Plan
• Research Business Plan

Reservoirs. Pipes. Treatment Plants.

IRWD is Orange County’s largest retail water district, providing water and sewer service to nearly 100,000 homes and businesses throughout the City of Irvine and portions of Tustin, Newport Beach, Costa Mesa, Orange, Lake Forest and unincorporated Orange County. Below are some key elements of our delivery and treatment systems.  

Deep Aquifer Treatment System: The Deep Aquifer Treatment System purifies drinking water from deep within the Orange County Groundwater Basin. The process removes impurities, left from ancient vegetation in the bedrock, and produces eight million gallons (mgd) of drinking water each day.

Irvine Desalter Project: The Irvine Desalter Project provides two key functions that help diversify our water resources. It removes salts from local groundwater to add to our local drinking water supplies. Separately, it cleans contaminated groundwater from the former El Toro Marine Corps Air Station to expand our irrigation water supplies. 

Michelson Water Recycling Plant: The Michelson Water Recycling Plant converts an average of 18 million gallons of wastewater each day into recycled water. The water is used for landscape irrigation, industrial uses and toilet flushing. The plant was built in 1961 and is IRWD’s primary source of recycled water.

Irvine Lake: Irvine Lake (formerly Santiago Reservoir) was built in 1931 to supply water for agriculture. It was opened to fishing ten years later. Today, IRWD shares ownership of the lake with Serrano Water District. The 700-acre lake holds more than 9 billion gallons of water and is contained by the 810-foot-tall Santiago Dam. 

San Joaquin Reservoir: The San Joaquin Reservoir was built in 1966 originally to store drinking water. After a law was passed prohibiting the storage of drinking water in open reservoirs, IRWD converted it to hold recycled water. Located in Newport Coast, this reservoir currently stores nearly a billion gallons of recycled water for future irrigation use.

Los Alisos Water Recycling Plant: The Los Alisos Water Recycling Plant converts an average of seven million gallons of wastewater each day into recycled water. The water is used for landscape irrigation and other non-drinking uses. The plant was built in 1964 and, along with the Michelson Water Recycling Plant, provides the District's recycled water supply.