Olivenhain Municipal Water District is a member of the San Diego County Water Authority and purchases all of its water supply from the Authority, who in turn purchases its water from the Metropolitan Water District of Southern California. MWD is a wholesaler that provides water to over 19 million people living in Southern California. 

MWD imports its water from two sources: a 242-mile-long aqueduct which transports Colorado River water from Lake Havasu to Southern California and a 444-mile-long aqueduct that transports water from the Sacramento-San Joaquin Delta in Northern California to Lake Skinner located in Riverside County.  The potable water is treated at the Robert A. Skinner Filtration Plant at Lake Skinner before delivery into OMWD’s distribution system.

The David C. McCollom ultrafiltration membrane water treatment plant allows OMWD to purchase less expensive raw water and treat it locally.

OMWD is committed to protecting its water sources, and continually looks for ways to increase its local supply. Programs include groundwater basin studies, recycled water, watershed outreach and education, and joint projects such as the Olivenhain Water Storage Project and the North San Diego County Regional Recycled Water Project.