Reducing water-hogging crops is the most impactful option (agriculture uses more than 80% of CA's non-environmental water use and agricultural water waste is mo

Reducing water-hogging crops is the most impactful option (agriculture uses more than 80% of CA's non-environmental water use and agricultural water waste is more than 99% of CA's water waste), but would require state (or very likely, federal) legislation. With the current political climate, and the likely outcome of the 2022 election, this option is the least likely to happen. Desalinization is not a magic bullet. Plants are expensive to build and to operate, even taking into account the use of passive renewables to provide most or all of the energy. There are currently 11 desalinization plants in CA (mostly in SoCal), the largest of which (in Carslbad, the largest such plant in the U.S.) can only provide enough water for 300,000 people a year. That is 30% of San Diego's water needs. CA's population is approximately 39 million. To scale up to the the entire state, we would need more than 120 additional plants just to address residential water use, for a cost of at least $120 billion (not taking into account inflation since the Carlsbad plant was completed). Reducing grass yards has been part of the playbook for several decades now. At this point, reducing grass yards amongst everyone except the superrich would have minimal impact because the rest of us have already heavily cut back. Gutter water flows to reclamation plants in most areas, but during storms flows directly to the ocean because the plants don't have the ability to handle the surge in flows. In SoCal, many water districts have begun using permeable asphalt to (re)pave streets so that rain water can absorb into the ground and recharge underground aquifers. A number of spreading pools and spreading grounds have also been built along storm channels, to provide areas where excess rainwater can collect and slowly absorb into the ground.