OMWD is a member of the San Diego County Water Authority, and thus purchases all of its water supply from SDCWA.  SDCWA in turn purchases its water from the Metropolitan Water District of Southern California. Metropolitan 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 Bay-Delta in Northern California to Lake Skinner located in Riverside Country.

OMWD's David C. McCollom Water Treatment Plant allows for local treatment of raw water, which is less expensive than purchasing water treated elsewhere. OMWD customers receive a blend of water treated primarily at the DCMWTP, but also at Metropolitan's Robert A. Skinner Treatment Plant and SDCWA's Twin Oaks Valley Water Treatment Plant.

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, and watershed outreach and education.

To learn more about the quality of your drinking water, please view our Consumer Confidence Report. For more information on fluoridation, visit our fluoridation page.

David C. McCollom Water Treatment Plant

OMWD’s David C. McCollom Water Treatment Plant consists of a membrane plant incorporating the latest ultra-filtration membrane technology. Ultra-filtration is a membrane filtration process that is considered a barrier process. The water from which the solids are removed passes through the membrane. This process provides a physical barrier to viruses and prevents the passage of solids larger than the pores in the membrane. This treatment method meets or exceeds federal water standards and allows for removal of water contaminants such as cryptosporidium.

An ultra-filtration plant has the lowest total capital costs compared to conventional treatment costs at $30 million for the first 25 million gallons per day (MGD) increment and $98 million for the full-capacity 34 MGD plant [this does not include total dissolved solids (TDS) or hardness reduction].

Because of the potential for varying water quality, OMWD requires flexibility in its treatment processes. Please see our brochure for more information. 

The Olivenhain Water Storage Project is an element of the San Diego County Water Authority's Emergency Storage Project for San Diego County. It includes the Olivenhain Dam and Reservoir. Details on the project can be found on SDCWA's website.