What are some reasons why there are no large scale fresh water desalination plants in California? Cost vs benefit. Desalination plants are incredibly expensive to initially build, also expensive to operate and maintain . Energy requirements are massive, and they don't produce very much fresh water.

California does use desalination, but it is not the primary water source because it is exceptionally expensive and environmentally controversial. As of 2026, the state has several plants, including the massive Carlsbad facility, but expansion is slow. The primary hurdle is cost: desalinated water can cost double or triple the price of recycled water or groundwater due to the massive amount of energy required for reverse osmosis. Additionally, there are major environmental concerns: the intake pipes can suck in and kill tiny marine organisms, and the leftover "brine" (highly concentrated salt water) can damage the ocean floor if not dispersed correctly. State regulators, such as the California Coastal Commission, maintain extremely high standards for new projects, often leading to the rejection of proposals (like the Huntington Beach plant) in favor of more sustainable and cheaper alternatives like stormwater capture and wastewater recycling.