Having non-existent or inconsistent regulations for potable reuse throughout the U.S. can be challenging, adds Cindy Wallis-Lage, president of Black & Veatch's global water business. As utilities or cities embark on DPR or IPR projects for the first time, there is a learning curve, she says. "How do we get to faster collaboration among multiple states, multiple regions of EPA?" she asks.

Moreover, professionals define terms—such as DPR and IPR—differently in different regions, she says. That can become problematic when specific terms are used in legislation and then migrate into regulations and standards for design, she says.

The WateReuse Association currently is working on a document to provide a range of common definitions to avoid confusion. But some sources say they would rather just use the term "potable reuse" to cover both IPR and DPR. "I've heard things like 'DPR-lite' [and] 'direct-direct potable reuse.' It just becomes … ridiculous because everybody is referring to a different thing," Labonte says.

Andrew Salveson, chief water-reuse technologist at Walnut Creek, Calif.-based Carrollo Engineers and a member of the panel that is overseeing the development of the facility at Cloudcroft, says small communities have unusual challenges, including securing adequate financial resources to build state-of-the-art projects and finding or training enough people to be skilled operators. "I think Cloudcroft represents a lot more than just Cloudcroft," he says. "It represents the small community throughout the southwestern United States that has a very limited water supply, and the technical and operational issues they face are different than what we find [with regard to] large utilities in big cities."

Some firms say that, large or small, communities can learn from one another and that they should be transparent about sharing information. Major forums for collaboration are conferences, where manufacturers, engineers and municipal leaders gather, says Alspach.

And the learning curve will inevitably grow shorter as the water sector overall collectively learns best practices and technological advances, he says.

Melissa Meeker, executive director of the WateReuse Association, notes that potable reuse may not be  something that every utility considers.

"Water issues are very local issues, so in different regions you have very different priorities … and I don't think you will see every utility in the U.S. going to DPR," she predicts.

That said, Meeker continues, "I do think you will see a more educated public open to considering water reuse in their water-sustainability conversations and understanding that [the supply] is not growing. We need to take advantage of every drop we have."