The transformation of Lake Mission Viejo into the first recreational lake in California to be fed with highly treated waste water instead of drinking water is expected to start in mid-November. On Monday, city, state and water district officials converged at the 124-acre man-made lake to celebrate the dedication of the project that will fill the lake with advanced purified water that experts say will be safe for swimmers and the lake’s fish. The project, which is going through final checks and maintenance, will save 114 million gallons of drinking water a year for residents in south Orange County, officials said.