New State Water-Use Regulation Offers Regional Benefits from Seawater Desalination

February 05, 2016

The San Diego County Water Authority is working with state regulators to certify the Claude “Bud” Lewis Carlsbad Desalination Plant…

The San Diego County Water Authority is working with state regulators to certify the Claude “Bud” Lewis Carlsbad Desalination Plant as a drought-resilient local supply source that will reduce state-mandated water-use targets across the region.

Changes to the state’s emergency drought response regulation adopted Tuesday by the State Water Resources Control Board provide a mechanism for the San Diego region to receive drought-resiliency benefits from the Carlsbad plant, which started commercial production in December 2015. With that facility now online, the Water Authority expects that state-mandated water-use targets for local water agencies will soon be lowered to align more closely with local water supply investments.

“The State Board’s decision is good news for our communities and ratepayers,” said Water Authority Board Chair Mark Weston. “These modifications recognize the need to take into account local water supply development efforts as well as increased conservation when implementing emergency drought response measures. Supplies from the Carlsbad desalination plant will reduce the need for extreme water conservation efforts in our region, an appropriate benefit for our proactive efforts to improve our water supply reliability by investing in the plant.”

The State Board revised its unprecedented water-use regulation that took effect in June 2015 and extended the new rule through October. It affords local water agencies that have developed drought-sustainable supplies since 2013 a supply credit of up to 8 percentage points toward the state-mandated water-use targets. The Carlsbad desalination plant provides the region with up to 56,000 acre-feet of drought-proof water each year, reducing the region’s reliance on other water sources.

Starting in June 2015, the State Board’s water-use regulation directed Water Authority member agencies to reduce water use by 12 to 36 percent through February compared to the 2013 baseline levels. Through the first seven months of mandates, total regional potable water use in San Diego County declined by 24 percent from June through December. That beats the state’s aggregate target of 20 percent for the region. Conserved water has been stored in the newly expanded San Vicente Reservoir since early May 2015.

The Water Authority expects to certify the desalination plant supplies with the State Board in early March and finalize the actual reductions to local agencies’ state-mandated water-savings targets. The revised water-use mandates for local water agencies will vary depending on their initial targets set in May 2015. However, the modified emergency regulation still requires that every local water agency reduce water use compared to 2013 baseline levels to ensure conservation continues during this drought emergency. The minimum reduction is 8 percent compared to baseline levels, but most agencies in the San Diego region will still need to meet higher savings targets. The State Board will reconsider its regulations after the peak snow conditions are assessed in early April.

Over the past several months, the Water Authority joined with its member agencies and local civic and business groups to advocate for state policies that reflected local water supply investments and conditions. The proposed modifications were designed to achieve important statewide water management goals in a more equitable and sustainable manner, allow communities to receive the benefits of their investments in water supply reliability and minimize unnecessary impacts to ratepayers.

“I want to give special thanks to the residents and business leaders who provided comments to the State Board and helped improve the regulation,” Weston said. “Water conservation is still important and we still must keep water use below 2013 levels to meet the state mandate, but we can now do so with fewer impacts to our economy and quality of life. Businesses will have more flexibility to conduct their operations, and residents will have greater leeway to replace their dead lawns with water-efficient landscapes. Together, we can continue to make the most of our precious water supplies as we seek additional improvements to the state’s drought response measures.”

More information about the State Board actions is at

  • The San Diego County Water Authority sustains a $268 billion regional economy and the quality of life for 3.3 million residents through a multi-decade water supply diversification plan, major infrastructure investments and forward-thinking policies that promote fiscal and environmental responsibility. A public agency created in 1944, the Water Authority delivers wholesale water supplies to 23 retail water providers, including cities, special districts and a military base.

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