About Us

Western Municipal Water District is securing your water supply for today and tomorrow.

Western is one of the largest public agencies in Riverside County providing water, wastewater (sewer), and recycled water services to nearly 1 million people, both wholesale and retail customers, across 527-square miles in western Riverside County.

Providing customers with an exceptional customer experience is our top priority, and we do this by pairing consistent delivery of safe, reliable drinking water and wastewater services with outstanding customer service. We view our customers as essential partners in ensuring long-term water security for our region.

Who we serve

Western has been serving the community since 1954, providing reliable water and wastewater services to wholesale and retail customers from Corona to Temecula. This regional area includes the cities of Corona, Norco and Riverside and the water agencies serving Box Springs, Eagle Valley, Lake Elsinore, Temescal Valley and Temecula. 

Western directly services approximately 25,000 residential and business retail connections located within portions of the cities of Riverside and Perris, as well as the unincorporated communities of El Sobrante, Eagle Valley, Lake Mathews, portions of Mead Valley and March Air Reserve Base. 

In 2005, with the merger of Murrieta's water utility agency, Western began serving a 6.5-square mile section of western Murrieta, primarily in the historic downtown area of the city. 

Rainbow is Western’s most distant served community is an unincorporated area of southern Riverside County bordering San Diego County.

Where your water comes from

As a member agency of The Metropolitan Water District of Southern California (MWD), the state’s largest water supplier, Western receives most of its water from the Sacramento-San Joaquin Bay-Delta by way of the California State Water Project (SWP). The SWP is a water storage and delivery system of reservoirs, aqueducts, power plants and pumping plants extending more than 700 miles, transporting your water from northern California to its final destination here in southern California entering the Western distribution system where it is closely monitored until it reaches your tap.

Western's water imported from the Colorado River travels more than 200 miles across the arid desert through open aqueducts and pipelines built by MWD in the 1930s.

Western has a groundwater supply in its Murrieta service area, which is combined with imported water for the region’s residents. Western also has rights to groundwater in the Bunker Hill Basin in the San Bernardino valley. Water from the basin is transported into our Riverside service area as part of an agreement with the City of Riverside/Riverside Public Utilities.

Protecting the source

Western is one of five member agencies of the Santa Ana Watershed Project Authority, a regional water resources planning and project implementation organization. 

As a water rights steward for the Santa Ana River Watershed, Western works to protect this important resource by carefully monitoring the quantities of water taken by all regional agencies with rights to this critical resource. Western’s general manager also serves as a court-appointed guardian or “watermaster”, as required by two 1969 court rulings or adjudications. These judgments determined the rights of the watershed users and other watershed entities. 

The court designated four public agencies – including Western – to represent the interests of the upper and lower areas of the Santa Ana River and gave the agencies the responsibility to oversee the watershed and fulfill court-ordered obligations. 

Western is involved in four watermaster functions: 

  • Santa Ana River – 1969 surface water rights 
  • San Bernardino Basin Area – 1969 groundwater adjudication 
  • Chino Groundwater Basin – 1978 groundwater adjudication 
  • Santa Margarita River – 1964 surface and groundwater adjudication