What power generation and sewage treatment have in common.

They're drinking sewage cocktails.

The struggle to get drought-parched citizens of the US southwest to drink sewage recycled into fresh water shows how conservation campaigns go wrong and how to fix them.

Take the greater San Diego area. It imports 90% of its water. It’s water sources are already drying up and drought is set to make the situation worse. Even knowing those facts, two attempts to win public support for programs to recycle sewage into drinking water have failed.

One of the few successes is El Paso TX, whose citizens are lapping up “toilet to tap.” 40% of its potable water is supplied from recycled sewage. El Paso’s public education campaign employs the “Mother Theresa” strategy.  That is, if you knew a mass murderer owned a very nice sweater you would still be creeped out by the thought of touching it. But if that sweater came into Mother Theresa’s hands before yours, and she wore it, you would want the sweater.

So, El Paso promised to pump its treated sewage into the ground. The water would percolate through underground rock and gravel before it enters the aquifer that feeds into El Paso’s fresh water system. Experts carped that the treated sewage might be dirtied in its passage to and through the aquifer. These appeals to reason failed to shake the public faith in the purity of nature.

Elsewhere, Singaporeans consume 3 million gallons a day of drinking water purified from sewage.

To win public support the government made it personal. Singapore, the campaign explained, had become dependent on uncertain foreign water supplies. This threatened national security and continued economic growth – the foundation of the wealth of each Singaporean.