Metropolitan Water District: Re-envisioning Water Delivery

The Metropolitan Water District of Southern California is re-engineering its water system to better serve communities that were disproportionately impacted by the severe drought in 2021-22. While Metropolitan delivers water from both the Colorado River and the Sierra Nevada to Southern California, some communities only have access to Sierra supplies, via the State Water Project. So when the last drought saw these state project supplies slow to a trickle, the nearly 7 million people in these communities were required to dramatically reduce their water use, or risk running out of water.

To prevent such threats in the future, Metropolitan is moving fast to build a series of four new infrastructure projects will help make these parts of Los Angeles, San Bernardino and Ventura counties more water resilient during future dry years. Looking to the future, as SWP supplies become more stressed, these communities will benefit from Metropolitan’s investments in re-engineering its water system to allow Colorado River water and water stored in Diamond Valley Lake to be delivered to more communities and freeing up SWP supplies for other parts of the system.

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Specifically, the redesign of Metropolitan’s water delivery system will:

  • Overcome new climate challenges: California’s systems of aqueducts and reservoirs were built decades ago and were largely built to deliver water from the Sierra Nevada snowpack. But how, when and where California receives precipitation is changing drastically. Even when our snowpack is limited, every California community needs a reliable water supply. The redesign of Metropolitan’s system will provide the necessary flexibility to ensure available supplies can reach more communities in the district’s service area.
  • Improve water equality: As California’s climate has changed, some communities have been disproportionately impacted by drought. The redesign of Metropolitan’s water delivery system will extend new water sources to many of these communities, lessening the impacts of drought by ensuring access to alternative water resources when needed and making available SWP supplies for the remaining communities with limited access to other supplies.
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Project Overview

For more than 80 years, Metropolitan has proudly provided Southern California with the water that has allowed the region to thrive and prosper, supplying 26 member agencies that collectively serve 19 million people over 5,200 square miles. Metropolitan has spent nearly a century developing a vast network of reservoirs, treatment plants, hydroelectric facilities and tunnels to get water to where Southern Californians use it.


Now, Metropolitan is again looking ahead – and making sure that water is available and equitable even in the face of a changing climate. The $110 million investment to reengineer Metropolitan’s water delivery system includes a series of four projects, consisting of new pipelines and redesigned pump stations, that will collectively push water from the Colorado River and Diamond Valley Lake, Southern California’s largest reservoir, into communities that currently have limited access to these diverse and stored supplies.

Specifically, customers served by Inland Empire Utilities Agency, Three Valleys Municipal Water District, and Upper San Gabriel Valley Municipal Water District will gain access to these vital water resources. The investment also will benefit the three other SWP-dependent agencies – Calleguas Municipal Water District, Las Virgenes Municipal Water District, and the Los Angeles Department of Water and Power – by making limited state project supplies more available to them.