Part 2: Santa Barbara famously built an expensive desal plant in the 90s which was promptly decommissioned because it started raining again. They’ve refurbished it and brought it back on line now.

If a city has multiple sources of water, they can turn to desal (or reverse osmosis of wastewater even) if they are running short. But the initial costs of building such a plant run into the hundreds of millions of dollars. Which raises the cost of water. And guess what? After a certain point necessary for cooking and hygiene, water consumers will cut back on water use if the cost rises. So a city could build a desal plant, then raise rates to pay for it, only to push their customers into conserving enough that they don’t have to run the desal plant. They could’ve just raised rates to manage demand, and not built the plant, saved $300 million, but in places like California it’s illegal to set rates like that.

A lot of California cities, 25%+ of water is used on lawns. That’s the culture after decades of underpriced water. Charge something approaching the real price, and people suddenly don’t want to be responsible for large swaths of ornamental sod any more. Places in the Middle East need desal. Most places in the US would have enough water if it was priced appropriately.