Water reuse advocates celebrated in May as the Denver City Council took the first step in creating a local program to help oversee graywater use in the city.

After reviewing a draft ordinance in front of the Safety and Well-being Committee on April 12, the first official reading before city council took place on April 25, making Denver the first city in Colorado to begin establishing a local program.

In 2014, House Bill 1044 authorized the Colorado Dept. of Health and Environment (CDPHE) to develop regulations so that graywater can be reused safely. Over a two-year period, the CDPHE’s Water Quality Control Division worked with stakeholders and other State of Colorado agencies to draft Colorado’s first graywater regulation.

On May 11, 2015, Graywater Control Regulation (Regulation 86) was adopted by the Water Control Commission. It outlined requirements, prohibitions and standards for graywater use for nondrinking purposes.

While developing the graywater program for the city, CDPHE and the Plumbing Board followed the guidance of other states that have implemented graywater programs, including Oregon, New York, Texas and New Mexico. However, because this program involves the general public, local officials decided to take a more rigorous approach.

“As Denver’s population grows, water conservation will be of continued importance,” said Sonrisa Lucero, sustainability strategist, city of Denver.  “The ordinance empowers the Denver Board of Environmental Health to develop regulations to govern the use of graywater within the city and empowers the Dept. of Environmental Health, in coordination with Community Planning and Development, to administer the program.”

Denver Water says that it estimates for every 1,000 graywater systems installed in single-family homes, enough water could be saved to serve about 125 households per year.

Further, water officials say that a graywater program will support the city’s 2020 Community Sustainability Goal for Water Quantity of reducing per capita use of potable water in Denver by 22% because it provides a new option to conserve water.

In an effort to address numerous health concerns, Colorado State University conducted a study on the long-term effects of graywater on soil quality, as a result of its application for residential landscape irrigation.

The research team collected soil samples at households with existing graywater irrigations systems that had been in place for more than five years in Colorado, California and Texas.

Results indicated that graywater irrigation may actually increase the rate of infiltration of water into soils, and long-term irrigation with graywater will most likely not result in reduced infiltration capacity. Additionally, the team found that areas irrigated with graywater may not have more pathogen indicators than areas irrigated with fresh water.

Industry professionals are already considering graywater for their further development projects. A development technology company called iUnit,  which builds energy-efficient, net-zero housing communities, has started incorporating smart-water meters in its units that can detect leaks down to a leaking flapper in the toilet— which can result in nine gallons of wasted water per day.

“A lot of people don’t realize the energy involved in our water systems and also how finite a resource potable water is,” said Brice Leconte, the founder of iUnit. “By incorporating graywater systems in our communities, we are able to address this issue and make better use of water.”

“Every day that we wait, there is another project that goes by without considering the application of graywater systems,” said Patti Mason, executive director, USGBC Colorado. “Regulation 86 is just one piece of broader water reuse conversation that’s underway in Colorado. As the city of Denver moves forward with graywater implementation, we anticipate seeing other growing communities across the state follow suit.”