A Voluntary Program to Boost California’s Climate Leadership

In 2016, the California State Legislature passed Senate Bill 1425 to support the state’s GHG reduction efforts. This bill required CalEPA to oversee the development of a voluntary registry for GHG emissions resulting from the water-energy nexus.

The Climate Registry, which has been managing GHG reporting programs since its founding in 2008, was awarded a contract to administer the Water-Energy Nexus Registry on behalf of CalEPA. TCR worked with water and wastewater agencies and other stakeholders throughout 2018 and early 2019 to design the GHG protocols and program policies that govern the Water-Energy Nexus Registry.

The Water-Energy Nexus Registry officially launched in May 2019. It is open to organizations with operations in California at no cost to participate. There are no minimum participation requirements.

For more information on the registry, please see the FAQs.


“The ability to comprehensively assess the relationships among water, energy and greenhouse gas emissions will lead to more efficient investments, more effective programs, and more resilient markets.”

– Frances Spivy-Weber, former Vice-Chair, California State Water Resources Control Board


What is the Water-Energy Nexus?

Moving, treating, and using water requires energy, and providing energy to businesses and homes requires water. This connection between our water and energy systems is the Water-Energy Nexus.

In California, about two percent of total energy consumption is related to the extraction, storage, conveyance, treatment and disposal of water, while end-use activities such as heating and cooling account for around 10 percent, according to the California Department of Water Resources. The energy required to power California’s water lifecycle contributes to its carbon footprint. Increasing the efficiency of our water system will support California’s state-wide GHG reduction target of 40 percent below 1990 levels by the year 2030.