Getting Closer to Governing Direct Potable Reuse

Colorado water providers are one step closer to getting guidance that could encourage them to reuse more water, thanks to a new report.

A National Water Research Institute-organized panel of reuse experts worked for 18 months to craft a report that details potential Colorado Department of Public Health and Environment regulations for direct potable reuse, which isn’t addressed in current regulations. Colorado has no active direct potable reuse projects, which move purified wastewater directly into drinking water facilities. Some communities are doing indirect potable reuse, which runs treated wastewater through an environmental buffer, such as a creek, before treating it for drinking.

The report is part of WateReuse Colorado’s efforts to follow up on the 2015 Colorado Water Plan, which said, “Widespread development of potable reuse will be an important facet of closing the future water supply-demand gap.” The plan said Colorado needed a clear regulatory framework on reuse if reuse is to help address that gap—a consequence of population growth, climate change and other challenges.

Getting this framework in place will give utilities the certainty they need to pursue direct potable reuse, which is critical for optimizing supplies they already have, says Laura Belanger from Western Resource Advocates. “We want them to use the supplies they already have to the fullest extent, and that will ideally leave water in our streams and rivers.”

The report prioritized health and recommended the state require three independent treatment technologies for both pathogens and chemicals. It said the state should establish limits for certain unregulated chemicals, including compounds that are toxic or newly discovered.

“We’re taking it to an extreme level of safety because we know it’s super important to protect public health,” says panel chair Larry Schimmoller from Jacobs.

The report’s expert advice provides a strong starting point for the state to move forward and give water providers the governance they’re asking for, says Ron Falco from CDPHE’s Water Quality Control Division. He hopes the division can find resources to start gathering stakeholder feedback later this year. Staff would then make recommendations to the Water Quality Control Commission for a rulemaking process.

To help overcome its reliance on non-renewable groundwater, Castle Rock Water aims to get one-third of its long-term supply from reuse. This year the town is completing upgrades to its Plum Creek facilities, which were designed for indirect potable reuse and possibly adding direct later. The direct option would move water within facilities rather than in the creek, increasing system reliability while reducing pumping costs and evaporative loss.

Reuse is a cost-effective approach that makes sense, says Mark Marlowe, director of Castle Rock Water. “This is part of what we need to do as a state to make sure that we have a reliable long-term supply.”

Dana Strongin is a freelance journalist, writer and editor based in central Colorado.