California Plans Nation's Largest Recycled Water Supply Program

Southern California is looking for ways to make better use of wastewater in what could become the largest recycled water supply program in the nation.

“The board of directors of Metropolitan Water District, Southern California’s largest water importer, has approved a plan to explore a large-scale regional treatment project to purify wastewater currently discharged into the Pacific Ocean and instead use it to recharge local groundwater basins,” BizJournals reported.

“The board authorized an agreement with the Sanitation Districts of Los Angeles County to develop a 1-million-gallon-per-day demonstration plant and also to establish terms and conditions for future development,” the report said.

The plan would require a significant facility upgrade for the district. “Metropolitan could ultimately build a new purification plant to produce up to 168,000 acre-feet per year at the sanitation district’s Joint Water Pollution Control Plant in Carson along with about 30 miles of distribution pipelines to replenish groundwater basins in Los Angeles and Orange counties,” district officials explained in a statement.

Metropolitan Board Chairman Randy Record explained the significance of the plan.

“The purified water produced by this program would represent a new drought-proof supply to help replenish the region’s groundwater basins, which typically produce about a third of Southern California’s overall water needs,” Record said. “Diversifying the region’s supply sources, advancing conservation and maintaining our imported supplies are all critical and complementary parts of our long-term water plan for Southern California.”

Using recycled water for groundwater recharge has a long history in California. “The Orange County Water District (OCWD) has been recharging with Santa Ana River water since it was formed in 1933. As the watershed became more populated, more of the river flow was comprised of treated wastewater. This river continues to be a source of replenishment for groundwater basins,” according to the Water Replenishment District of Southern California.

More recently, Orange County “began operation of the Groundwater Replenishment System, which utilizes microfiltration, reverse osmosis, ultraviolet light to produce recycled water that is used for percolation in ponds and for seawater barrier protection.”

The entire state of California is experiencing abnormally dry or drought conditions, according to the U.S. Drought Monitor. The state has been languishing in extreme drought for four years.

For more on the Western drought, visit Water Online’s Water Scarcity Solutions Center.