Olivenhain Municipal Water District is a public agency providing water, wastewater services, recycled water, hydroelectricity, and the operation of the Elfin Forest Recreational Reserve.

OMWD is a Municipal Water District organized and operating pursuant to Water Code Sections 71000 et seq., and was incorporated on April 9, 1959, to develop an adequate water supply for landowners and residents. On June 14, 1960, residents of OMWD voted to become a member of the San Diego County Water Authority, thus becoming eligible to purchase water transported into San Diego County via the massive aqueducts of SDCWA and its wholesaler, Metropolitan Water District of Southern California. At over 48 square miles, OMWD currently serves a population of approximately 80,000 residents in northern San Diego County.

Potable Water Operations

• 17 water storage reservoirs with a capacity of nearly 80 million gallons of water
• Over 27,000 meters are served
• Over 400 miles of potable water pipeline
• OMWD’s David C. McCollom Water Treatment Plant treats up to 34 million gallons of water each day 

Wastewater/Recycled Water Operations

• OMWD’s 4S Ranch Water Reclamation Facility produces up to 2 million gallons per day of recycled water
• 46 miles of recycled water pipeline
• Sewer service to 6,600 dwellings in 4S Ranch and Rancho Cielo

Elfin Forest Recreational Reserve

• 784 acres of natural habitat in the heart of North County
• 11 miles of trails for hikers, bikers, and equestrians