[hawkice]

Essentially, water is subsidized by the Californian water pricing rules in order to provide low-cost feed that boosts milk production in cows (this is why alfalfa in particular probably won't be pushed out). Californian dairy is a surprisingly powerful lobbying group with enough of a budget to also have a general public ad campaign to protect their interests.

The price subsidy encourages overconsumption, which causes the shortage.

Most places raise prices to fund desalination plants (if they have access to large bodies of water near the population centers, like California does), but that's why they don't. And given they won't do the obviously ideal strategy that works for everyone else in the world, it's been hard to get money from the struggling general budget to build the facilities. Why should every other department struggling for a budget to meet basic needs lose their chance because they won't adopt a simple price structure change?

Instead, non-renewable reserves are being depleted, as mentioned in the article.

The problem here isn't really technical in nature, though.

[CN7R]

I don't think the current model of agricultural production in California is sustainable; for something that takes up 70-80% of the state's water, it only amounts to 2-2.5% of the GDP.

If the problem for California is one of policy, what endeavors can technology take on to help?

[hawkice]

Develop tech to make alternate feed cheaper without dropping milk production or quality compared to alfalfa.

Improve water distribution in soil (I think there is a way to optimize this, varying by soil type and many other factors, that would minimize runoff). Or, get easier systems to recycle runoff. Ideally something with no/few moving or manufactured parts.

Reduce the cost of desalination plants and create a more realtime water market. Having one single water market would be a fundamentally technical task (albeit a complex one), but would level out prices, removing the incentive to make the policy mistakes.

[Detect]

Farmers are sunlight harvesters. Figuring out how to turn sunlight + carbon dioxide (renewables) into profitable products for sale can be achieved through good management in addition to appropriate technology.

Soil's water holding capacity can be increased through techniques like green mature and cover cropping. The permaculture approach to water is to slow it, spread it, and sink it.