Graywater

The Denver Department of Public Health & Environment (DDPHE) promotes sustainable water use through the Graywater Program, which educates Denver residents about using graywater in their homes. The program provides guidelines and resources for safe implementation, helping participants reduce freshwater consumption and lower water utility costs.  

Colorado’s Water Plan (CWCB, 2023) details the water supply shortfall Colorado is facing and describes actions to help reduce the shortfall. One strategy the plan identifies is the reuse of graywater. Graywater reuse systems are an effective way to reduce water consumption for any type of building or home. When used for drip irrigation and for flushing toilets, graywater can help save Colorado’s limited water supplies. 

What is graywater?

Graywater is wastewater that originates from a clothes washer, bathtub, shower, or bathroom sink and can be used in your home for certain types of irrigation or for flushing toilets. 

Graywater is different from “black water,” which is wastewater from toilets, kitchen sinks, and dishwashers. Blackwater is not safe for reuse in the home because of the high risk of contamination by bacteria, viruses and other pathogens.

Every time we shower or wash clothes, we create graywater that is usually disposed of. Residents can lower their water bills and conserve a valuable resource by installing systems that allow them to reuse graywater. Graywater can be used for landscape irrigation and toilet flushing. Find out more about reusing graywater below.