Water Supply & Reliability

Water. It’s why Irvine Ranch Water District was created over 50 years ago. The District provides high-quality drinking water to more than 370,000 residents. Water is a vital resource, requiring careful management to ensure the needs of present and future generations are met. Through thoughtful planning and prudent fiscal policies, we cost-effectively manage our water portfolio, while continuing to diversify supplies to enhance future reliability.

Since our inception, we’ve not only delivered water, but also value in all we do for our customers and the region. IRWD is known for its progressive programs. From providing quality water, to diversifying our water portfolio and planning now to ensure future water supplies – we believe in going above and beyond to work efficiently, cost effectively and in an environmentally sensitive way.

delta waterwayIRWD has a diverse water supply portfolio to keep rates as low as possible. Everyone’s heard the adage “don’t put all your eggs in one basket.” In the water business that means not relying on just one source of water. IRWD is committed to providing a highly reliable water service. We work hard to ensure our customers have diverse sources of water for increased reliability now and in the future.

Some parts of Orange County are 100 percent dependent on water from outside this area. Not so at IRWD. We've worked hard to decrease our dependence on costly imported drinking water. Finding new sources of water is critical to ensuring water reliabiity for our customers. Since the late 1970s we’ve been building a network of local wells to ensure reliability and reasonable costs. After all, local water costs less than water that must travel hundreds of miles through aqueducts to reach Southern California. IRWD's drinking water comes from two primary sources: local groundwater and imported water. The blending of these sources varies according to the time of year and your geographic location within the District. IRWD manages its supply and demand with careful research and analysis regarding flow, diversions, climate, customer demand and population estimates to ensure there will be an adequate supply of clean, reliable water well into the future.

IRWD's drinking water comes from two primary sources: local groundwater and imported water. The blending of these sources varies according to the time of year and your geographic location within the District. In addition, IRWD has a robust recycled water program. Every drop of recycled water used for irrigation or other non-potable purposes saves drinking water. The District's diversified supply ensures a reliable water supply during times of drought, regulatory constraints and other emergencies. Additionally, our diverse water supply portfolio helps to keep rates as low as possible.   


Approximately 48 percent of our overall supply comes from local groundwater wells in the Orange County Groundwater Basin, and the Irvine and Lake Forest sub-basins. For many years, IRWD received almost all of our water from imported sources. To alleviate this dependency on costly imported water, IRWD began to develop a series of local wells in 1979. The Dyer Road Wellfield Project extracts low-cost, high-quality water from deep within the Orange County Groundwater Basin. IRWD now operates 25 groundwater wells within our service area. Click to learn more about IRWD's Groundwater.

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 Imported Water


IRWD purchases 27 percent of it's water through the Municipal Water District of Orange County, who purchases water from the Metropolitan Water District of Southern California (MWD), a regional water wholesaler that delivers imported water from Northern California and the Colorado River.

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State Water Project

The State Water Project, also known as the California Aqueduct, transports water 600 miles from Northern California to the southern portion of the state. It is owned and operated by the State of California and is the longest aqueduct system in the world, featuring 23 dams and reservoirs, 22 pumping plants that lift water to heights of 3,500 feet, and six power plants. The aqueduct is comprised of 473 miles of canals, 175 miles of pipeline and 20 miles of tunnels.

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Colorado River Project

The Colorado River Aqueduct brings water 242 miles from the Colorado River through deserts and over mountain ranges to its terminal reservoir, Lake Mathews, in Riverside County. The aqueduct system includes five pumping plants that lift the water 1,617 feet.

 Recycled  Water

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IRWD produces approximately 21 percent of our supply by capturing water that normally would run out to sea, treating it, and reusing it for irrigation and other non-potable, or non-drinking, uses. We also supplement our supplies by cleaning non-potable groundwater to make it suitable for irrigation. Every gallon of recycled water and cleaned groundwater we use saves a gallon of drinking water. Click to learn more about IRWD's Recycled Water Program.

 Water Banking

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Located in Kern County, the Strand Ranch Water Banking Project improves IRWD's water supply reliability by capturing low cost water available during wet years for use during periods of drought or critical need. Using a system of 502 acres of constructed groundwater recharge ponds on Strand Ranch, IRWD can store up to 50,000 acre-feet in the Water Bank and may recharge or recover up to 17,500 acre-feet in any single year. Click for more information about Water Banking.

On July 24, 2018, the California Water Commission voted to conditionally award the Kern Fan Project $67.5 million. IRWD and Rosedale are now working to complete additional requirements outlined in the program regulations in order to execute a final funding agreement and receive funds.

Water Supply Reliability Program




IRWD has purchased property in Riverside County that is located within the Palo Verde Irrigation District. Ownership of this land will eventually become another element of IRWD’s long-term program to increase water supply reliability for its customers during droughts and other potential water supply interruptions. This land is currently farmed by a tenant farmer; IRWD expects to continue with the practice.  For more information please click here.