Virtual Tour of the Water Journey

A Brief History of Western


Until the late 1970s, the District’s sole source of imported water was the Colorado River. However, because of the mineral content of this water source, many communities within Western’s District have increasingly come under pressure to improve the quality of effluent discharged into the Santa Ana River Basin. One solution was to begin importing Northern California water, with its lower salt content, which had become available with the construction of the State Water Project. Western began supplying Northern California water, treated at Metropolitan’s Henry J. Mills Filtration Plant in Riverside, in 1979.

During the years since Western was approved by the voters, the District has served a leadership role in groundwater management and water resources protection. Western has worked to educate the public about the importance of conserving water resources. These programs are an important component of Western’s role as a supplier of imported water. Without a reliable imported water supply, western Riverside County’s homes, industry, and agriculture would not be as they are today. Yet, because this water is imported, conservation and responsible management of it and all local water resources are vital. Since 1954, Western Municipal Water District of Riverside County has provided both. 

Bringing Water to Southern California. For nearly a century. 

The Metropolitan Water District of Southern California has helped Southern California grow and thrive by delivering high-quality water to our region. Now they are helping the region meet the challenges of climate change and extended drought. 

Where your water travels from

From Source to Tap.

Follow the extraordinary journey your water must take before you use it, from sources high in the Rockies and the Sierra Nevada, through critical purification processes, to homes and businesses across Southern California.

Take a virtual tour and see precisely how water flows into western Riverside County for availability at the turn of a tap for you. 

Chose an adventure:

The State Water Project - Capable of delivering water to 27 million Californians and three-quarters of a million acres of farmland, the California State Water Project is the largest state-built water and power system in the nation. The project that spans more than 700 miles down the heart of the state is operated and maintained by the California Department of Water Resources. The California Legislature passed the Burns-Porter Act in 1959, which authorized $1.75 billion in bonds to construct the initial facilities. Voters approved the sale of the bonds in 1960. In addition to providing drinking and irrigation water, the project is operated to improve water quality in the Delta, provide flood control and recreation, and enhance fish and wildlife.

The Metropolitan Water District of Southern California Distribution and Treatment System - Metropolitan’s responsibility to deliver reliable water to Southern California cannot be understated. Neither can our vast storage and distribution system. They operate and maintain an expansive range of reservoirs, water treatment plants, hydroelectric facilities, large-diameter pipelines and tunnels, and about 400 service connections that distribute water imported from hundreds of miles away to 26 member agencies, which then deliver it to the taps of 19 million people across 5,200 square miles, including right here in western Riverside.

Maintaining their vast infrastructure, built for flexibility and resilience, is no simple task. Investments in infrastructure ensure their water system, which began operating in 1941, remains reliable now and into the future.

The Colorado River Aqueduct - The Colorado River Aqueduct is a 242-mile system comprised of open canals, tunnels, and siphons that carry millions of gallons of water daily from the Colorado River across the desert to the people of Southern California. The engineering marvel was built in the 1930s, as the nation emerged from the Great Depression, and immediately became an essential element in creating the vibrant Southern California we know today. The system works by pumping water up to higher elevations at five different points along the aqueduct and then allowing it to flow downhill by gravity.