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.
There are two kinds of water: treated water, which has been cleaned up for drinking; and raw water, which comes from a river or reservoir and is not yet fit for human consumption.