The Diemer plant treats water from both the Colorado River Aqueduct and the State Water Project. The facility has a treatment capacity of 520 million gallons a day.
The plant has been retrofitted for ozone treatment, which went online in 2015. It is the fourth of Metropolitan's five treatment plants to provide ozone treatment. The fifth, the F.E. Weymouth Treatment Plant, is scheduled to be online in 2017.
The facility is also home to the 5.1 megawatt Yorba Linda Hydroelectric Power Plant, which generates power by taking advantage of the powerful force created as water rushes down the pipelines leading to Diemer. The power plant is one of 16 such facilities built by Metropolitan along its conveyance and distribution system. Energy from the Yorba Linda facility is used to supplement Metropolitan's overall energy needs.
The plant is named after Robert B. Diemer, who started at Metropolitan in 1929 and eventually rose to chief engineer and was general manager from 1952 to 1961.
The Robert B. Diemer Treatment Plant3972 Valley View Ave.Yorba Linda, CA 92886(714) 528-7231