Report: Water and energy in California
California’s water system uses energy to pump, convey, treat, and heat water. Although agriculture uses roughly four times more water than cities, cities account for most water-related energy use. Water is also required for hydropower generation, thermoelectric power plants, and oil and gas extraction. Improving water use efficiency can reduce energy consumption; conversely, improving energy efficiency can reduce impacts on water supply and quality. … The water system uses approximately 20% of the state’s electricity and 30% of its natural gas for business and home use, according to data from 2001—accounting for more than 5% of California’s greenhouse gas emissions.