Turns out one of the single biggest sources of energy use in your home doesn't even show up in the electricity section of your utility bill. 

In California today, just delivering water accounts for 20 percent of the state's energy consumption. It takes power to gather water, purify water, and distribute water, especially in places like southern California where water is piped hundreds of miles to supply Los Angeles' sprawling demands.

On the flip side, producing power requires a great deal of water. Nothing in this country, aside from agriculture, uses more water than power production.

So if fresh water is required to make power, and it takes power to purify and distribute fresh water … well, you can see where this is going: A Mad-Max style future in which the only clothing left is the cast-offs from 80's hair bands and leather daddies.

Nationally, [this is] a challenge, but regionally it could be a calamity. As the Congressional Research report notes, "much of the growth in the energy sector's water demand is concentrated in regions with already intense competition over water."

Other worrying trends: Climate change is going to make water even more scarce in some areas of the country, and new fuels like ethanol and shale gas are even more water-intensive than the old-style fossil fuels they replace. So if you don't know what a "navy shower" is, you better learn quick.