There’s a Surprising Use for the Water You Flush Down the Toilet

Rivers in America have long featured wastewater—water that has been used in some way, like in a sink, shower, or toilet—as an ingredient.

Treatment plants became more common in the late 1800s but did little more than remove solids before piping the rest out to the ocean, wetlands, and rivers.

The turning point came in the 1970s with the Clean Water Act , which introduced some of the first water pollution regulations.

Highly treated wastewater presents an opportunity to do better than simply not causing harm.

In the U.S. Southwest , which has been plagued by drought for decades , many turn to recycled water as a resource for irrigating crops, tending golf courses, recharging groundwater, creating ski-resort snow, and even replenishing aquifers used for drinking water.