Our energy system depends on water. About half of the nation’s water withdrawals every day are just for cooling power plants. In addition, the oil and gas industries use tens of millions of gallons a day, injecting water into aging oil fields to improve production, and to free natural gas in shale formations through hydraulic fracturing. Those numbers are not large from a national perspective, but they can be significant locally.
We need to reuse our water, and conserve our water. This is really true on a global scale, as water wars are literally being fought in some areas of the world.