Lol no. It's as simple as boiling the water.

It's expensive and you need to build the infrastructure to do it on the large scale. But it's been implemented before. If California was smart they would have implemented it already but they can't even manage to build a train line let alone bother with long sighted infrastructure development plans. For a place with such restrictive environmental laws their blindspots are enormous. Hell they still just dump their sewage straight into the ocean.