Lake Mission Viejo first recreational lake in California to use Advanced Purified Water for refill

Water district, City and HOA join to in public/private partnership
to make historic change in water use in Orange County

Santa Margarita Water District officials were joined by Mayor Frank Ury, Mission Viejo; Fran Spivey-Weber, Vice Chair of the State Water Resources Control Board; Kevin Pennington, President of the Lake Mission Viejo Homeowners Association, and other local and state elected officials and dignitaries to celebrate the new system that will, for the first time ever, fill Lake Mission Viejo with 114 million gallons of Advanced Purified Water in lieu of potable water.  This new system will reportedly save that potable water for other uses and make Lake Mission Viejo the largest swimmable lake in the state; perhaps the nation, to use advanced purified water.

The treatment method involves taking already highly treated wastewater and treating it further in a process that includes advanced filtration tanks, reverse osmosis and ultraviolet light.  This additional purification makes it safe to supply the lake for swimming and other recreational activities. 

“In the last three years, as the current drought has intensified, the question of the lake-fill water, the use of drinking water for that purpose, has taken on new, critical importance,” said SMWD Board President Charley Wilson.  

“It was last year, when the District, our constituent cities, and all of our customers became intensely focused on the demands of the drought that this simple, but profound idea of taking our already highly-treated recycled water and providing an extra level of treatment to meet the lake fill requirements, brought all these partners together to find and effect a change that would benefit all the parties.”

Fran Spivey-Weber, Vice Chairwoman of the State Water Resources Control Board, called the project a model for water providers across the state.

Dignitaries at the ceremony symbolically put the first of the Advanced Purified Water into the lake from fishbowls containing fish that inhabit the 124-acre lake.

Ironically, the state was gripped by drought when the lake was built in 1976. It was finally filled in 1978.   The lake loses about 500,000 gallons a day to evaporation--enough water to supply about 1,400 families for a year.

In 2015, as the current drought continued to tighten its grip on the state,  SMWD officials grew concerned about continuing to pump drinking water into the recreational facility.

The water district approached the Lake Mission Viejo Association last year about using Advanced Purified Water to replenish the lake. Homeowners overwhelmingly approved the change.  The City of Mission Viejo subsequently agreed to loan SMWD $3 million for the project and also provide a $1 million grant to help the water district build the new treatment facility to purify the recycled water. The water district will pay off the loan over 20 years, at 2.5 percent interest. The agreement also calls for the city to receive enough recycled water to irrigate about 80 percent of its parks, medians and slopes for 25 years at a discount. The Lake Association will repay Santa Margarita an estimated $5.1 million in construction costs over 20 years.


 Santa Margarita Water District Board President describes the historic importance of the Lake Mission Viejo Advanced Purified Water Facility to the region.  Pictured (l to r) SMWD President Wilson; State Water Resources Control Board Vice Chairperson, Fran Spivey-Weber; City of Mission Viejo Mayor, Frank Ury; Lake Mission Viejo Homeowners Association President, Kevin Pennington


 State Water Resources Control Board Vice Chairperson, Fran Spivey-Weber expressed the appreciation of the SWRCB to SMWD and partners for taking on an innovative solution to water-savings with the implementation of the Lake Mission Viejo Advanced Purified Water Facility.  Pictured (l to r) Santa Margarita Water District Board President, Charley Wilson; Vice Chairperson, Spivey-Weber; City of Mission Viejo Mayor, Frank Ury; Lake Mission Viejo Homeowners Association President, Kevin Pennington


 Lake Mission Viejo Advanced Purified Water Facility partners and guests prepare to put into Lake Mission Viejo the first of the new advanced purified water—along with some new, healthy fish.  Pictured (l to r) SMWD Board President Charley Wilson; Mission Viejo Mayor, Frank Ury; SWRCB Vice Chairperson, Fran Spivey-Weber; 73rd District Assemblyman, Bill Brough; Lake Mission Viejo Homeowners Association President, Kevin Pennington

Learn more about the Advanced Purified Water Project at

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