In this May 2015 photo, Catarina Negrin holds preschooler Alana Nichols while standing near a graywater filtering system outside her home in Berkeley, Calif. Graywater is recycled waste water from kitchen appliances, bath tubs, showers and sinks.

(AP Photo/Eric Risberg)

So you recycle your cans, newspapers, and even your old cell phone. But how about your water? That’s the concept behind graywater, the used water that comes from your laundry machine, bathroom sink, or shower. Once the water is collected, it's re-used to water plants or flush the toilet.

Lawmakers passed a bill in 2013 allowing for graywater use in Colorado, but the practice has gone virtually nowhere.

The Colorado chapter of the U.S. Green Building Council works to ensure that buildings in the state are environmentally friendly. Patti Mason, the chapter's director, said the use of graywater is prevalent in states like Oregon, Texas and New Mexico. But in Colorado the practice is still not widely utilized.

The 2013 Colorado legislation stipulates that a new legal framework must be created before graywater usage can occur in the state. And because this is not a statewide program, local jurisdictions must then create their own graywater programs using regulations and best practices developed by the state. Those regulations come from Colorado's Water Quality Control Commission as well as the state's Plumbing Board.

But since that legal framework continues to be developed at this point, Mason said the use of graywater in Colorado remains stagnant.