The San Diego County Water Authority’s use peaked in 2002 at 732k acre feet. Last year it was down to 522kaf, a 29 percent drop even as population has risen by 12 percent. This is one of many examples of “decoupling” between growth and water use. As we adapt to conditions of increasing water scarcity in the western United States, this is a good thing. But as Ry Rivard reports in Voice of San Diego, there are downsides:

Over a decade ago, Southern California water officials rushed to build or expand treatment plants so they could keep up with the demand for drinkable water. That cost hundreds of millions of dollars.

Now demand for water has fallen dramatically. The treatment plants sit largely unused during parts of the year and officials are fighting over how to pay for some of them.