Metropolitan is the nation's largest wholesale water agency, delivering a reliable supply of imported water to its 26 member agencies serving nearly 19 million people and thousands of businesses in its six-county service area. It operates a complex storage and distribution system that includes an extensive range of reservoirs and distribution pipelines and facilities. The distribution system is comprised of hundreds of miles of pipelines and tunnels, and about 400 service connections of member agencies that in turn provide water across 5,200 square miles.
Since 2009, Metropolitan has doubled the amount of water stored in reservoirs like Diamond Valley Lake in southwest Riverside County, local groundwater basins and in water banking programs in Lake Mead and the San Joaquin Valley. Today, Metropolitan has 13 times more water storage capacity than it did in 1980.