The Irvine Ranch Water District is an independent special district serving Central Orange County, California. We provide high-quality drinking water, reliable wastewater collection and treatment, ground-breaking recycled water programs, and environmentally sound urban runoff treatment to more than 330,000 residents.
The District provides potable water to a population of 330,000. Approximately 65 percent of the drinking water supply comes from local groundwater sources pumped through IRWD’s extensive well system. IRWD treats this water at its disinfection facilities before it enters the distribution system of more than 1,200 miles of pipelines. The remaining 35 percent of IRWD’s drinking water comes from the Colorado River and the State Water Project and is imported by the Metropolitan Water District of Southern California (MWD). MWD treats these supplies to drinking water standards and IRWD distributes the water through our distribution system.
IRWD's sanitary sewer system collects all wastewater coming from homes and businesses within the IRWD service area. Sewage is conveyed to two treatment plants through more than 800 miles of sewer distribution pipelines. The Michelson Water Recycling Plant in Irvine treats up to 18 million gallons of wastewater per day while the Los Alisos Water Recycling Plant in Lake Forest treats up to 5.5 million gallons per day.
IRWD’s water reclamation plants treat incoming wastewater to tertiary treatment standards for use as recycled water. IRWD was the first water district in the state to receive an unrestricted use permit from the state for its recycled water, which means that this water can be used for any purpose except drinking. The majority of recycled water is used for landscape irrigation in parks, golf courses, school grounds, city street medians, homeowner associations and other public areas. Recycled water is also used for toilet flushing and cooling towers in more than 40 office buildings, and for industrial uses such as carpet dyeing and concrete making. IRWD maintains a completely separate recycled water pipeline system, also known as purple pipe, of more than 400 miles serving more than 4,500 metered connections.
Urban Runoff Treatment
Rain and urban runoff - from landscaping, car washing and other outdoor uses - flow into storm drains and out to the ocean bringing a wide variety of pollutants along for the ride. While counties and cities have primary responsibility for storm drains, IRWD began an innovative program in the early 1990's to use reconstructed wetlands to naturally treat urban runoff before it flows to the ocean. IRWD's Natural Treatment System diverts water from San Diego Creek to wetlands for a period of 7-10 days. Plants and soils within the ponds naturally remove nitrates and other pollutants from the water before it returns, much cleaner, to the creek to continue its journey to Upper Newport Bay and the ocean.