Whenever California is pummeled by drought — as is still very much the case despite recent rain — a lot of people find themselves asking, “What if we got water from the ocean?”

In San Diego County, it’s already happening at a $1 billion facility by the beach.

Recently, as I reported on San Diego’s decades-long quest for water stability, I visited the Carlsbad Desalination Plant, the largest such facility in the country, to see how it works.