Originally constructed in 1993.
Used as a water source for nondrinking purposes, such as irrigation of avocado orchards.
Provides water to Baker and Howiler treatment plants, which process drinking water for 85,000 O.C. homes.
The primary purpose of Irvine Lake (Santiago Creek Reservoir) is to store water – initially to provide irrigation for farms and more recently to satisfy urban water demands.
IRWD manages Irvine Lake’s water levels, ensuring customers have a reliable source of water while minimizing evaporation of water from the lake. IRWD also ensures the lake is able to effectively capture rainwater from surrounding hills, which reduces the cost of providing drinking water to customers.
IRWD conducts extensive routine monitoring of Irvine Lake to ensure water quality remains high.
The lake’s watershed is subject to sanitary surveys every five years to determine if there are any threats to water quality present. The most recent survey in 2019 found that the local watershed is predominantly rural, and wildfires and septic systems are the primary threats to water quality.
During years with less rainfall, IRWD adds untreated imported water to Irvine Lake purchased from the Metropolitan Water District of Southern California, which also conducts extensive monitoring of federal and state-regulated constituents, as well as many additional water quality parameters.
Limited shoreline fishing is permitted at Irvine Lake, with recreational activities managed by OC Parks.
