Wastewater treatment technology has made remarkable advances in the last 100 years, a far cry from when we commonly dumped raw sewage straight into our waterways. And the technology exists to treat wastewater to the point where it can meet drinking water quality standards. A number of scientists, engineers, and environmental groups have promoted the reuse of so-called graywater for drinking water as an important tool in our drinking water toolbox.

But the public still says “ick.” According to a recent study, it’s hard for people to set aside the knowledge that the water was once in contact with sewage. The irony, of course, is that if your drinking water source is a surface water body, you are almost certainly drinking some treated wastewater. For example, Aurora gets some of their drinking water from the Fox River, which contains treated wastewater from upstream communities such as Elgin, St. Charles, and Batavia. This treated wastewater also plays an important role in maintaining flows in most rivers in Illinois; wastewater discharge was the only source of water in some of them during the drought this year.

Orange County, California, is the largest user of treated wastewater for drinking water in the country. They don’t discharge their effluent (70 million gallons a day) into a river, but into a basin that replenishes an aquifer. This passage through sediments seems to make people feel better, even though it’s not clear that there is any improvement in the water quality because of this.

A couple in Oak Park recently installed one of the first graywater systems in Illinois in their home. They’re reusing water from their bathtubs and showers not for drinking, but for use in flush toilets. It’s a clever system. The most difficult part was getting the proper permits, since the current plumbing code doesn’t allow for reuse of graywater. The code is currently being modified to address this shortcoming.

Whatever you think of graywater, it’s definitely going to play a role in our water use in the future.