Lake Mission Viejo may soon be filled with purified recycled water

The group that operates a private lake in Orange County has proposed building a $5-million purification facility so it can begin using recycled water instead of the potable supplies it has relied on for decades.

As state regulators demand conservation in the fourth year of drought, the Lake Mission Viejo Assn. board of directors voted last week to put a proposal before its delegates for a plant that would send recycled water through additional purification processes and then into the lake.

The delegates are scheduled to vote June 2. Santa Margarita Water District officials estimate that the plant could be operational within six months of environmental review.

“Making the lake more sustainable is the right thing to do, drought or no drought,” Kevin Frabotta, the lake association’s general manager, said in a newsletter.

The district’s recycled water is already safe to swim in, but lake officials say the proposed “advanced purified water” would be so clean it could improve the lake’s overall water quality.

The association would pay for the plant, said Laer Pearce, a spokesman for the association.

The Lake Mission Viejo Assn. has come under fire in recent months because officials fill the 1.2-billion-gallon lake with drinkable water. Similar criticisms surfaced during a drought in the 1970s. Use of the lake for fishing, swimming and sailing is reserved for members and their guests.

During dry years such as 2014, the association purchases more than 114 million gallons of drinkable water -- about 350 acre-feet -- from the Santa Margarita Water District to maintain lake levels as water is lost to evaporation and seepage. That is enough to serve about 700 families for a year.

Talks about alternative water sources for the lake intensified earlier this year as state officials stressed the need to conserve. On April 1, Gov. Jerry Brown ordered a mandatory 25% cut in urban water use.

Under the state water board’s current plan, the Santa Margarita Water District must cut its usage by about that much over the next several months to comply with Brown’s executive order.

“If we can get the lake off our potable system, that’s a noticeable difference,” district spokesman Jonathan Volzke said. “In the back of our minds, its always been something that has needed to be addressed. This is a perfect opportunity to provide a long-term solution.”

The Santa Margarita Water District has already implemented Stage 2 water restrictions. Stage 3 would force the lake association to obtain a permit to replace water lost to evaporation from potable sources. Stage 4 would ban such filling altogether.

Refilling the lake with purified recycled water, though, would not violate any of the district’s water rules.

If the plan is approved, Pearce said Lake Mission Viejo would become the first swimming lake in California to use recycled water for lake refill.

Follow @ByMattStevens for coverage of the California drought.