Scientists are developing toilets that do not use water. Water is a limited resource, but each year 1.5 trillion gallons of clean drinking water are flushed down toilets in the United States.

Three promising types of waterless toilets are solar toilets, composting toilets, and bio-toilets. Each of these toilets recycle human waste into something useable.

Solar toilets burn up waste using the energy of the sun. Waste is cooked until it becomes a charcoal-like substance called “bio char,” which can be used as fertilizer. 

Composting toilets work like a garden composter. Most of these toilets have a spinning drum that inserts air into waste and compacts it. The compost created can be used for gardening. 

Bio-toilets use bacteria to break down waste in an underground tank. Gas from the tank can be used to power gas appliances and generate electricity.

Waterless toilets may be common in the future, but don’t wait to start conserving water in your bathroom. “Install toilets that use less water,” recommends Mary-Madison Phillips, a University of Arizona student majoring in Sustainable Built Environments. 

Some older toilets use up to seven gallons per flush, while eco-friendly flush toilets use around 1.5 gallons. Also, consider flushing less often. A common saying among water conservationists is “if it’s yellow, let it mellow; if it’s brown, flush it down.”