New Purified Wastewater Rules Expand Arizona Cities’ Capabilities

As water scarcity poses a critical challenge, cities across Arizona are leveraging innovative solutions to secure their water supplies. Recently, the Arizona Department of Environmental Quality (ADEQ) introduced regulations allowing municipalities to deliver advanced purified wastewater directly to residents’ taps.

Previously, cities utilized this treated water indirectly, reintroducing it into aquifers or other water systems before extraction. The new guidelines change that landscape, permitting immediate consumption.

Advanced purification entails a rigorous multi-step process that meets state drinking water standards. Key techniques include ultrafiltration, reverse osmosis, ultraviolet light disinfection, and advanced oxidation, all designed to eliminate contaminants and pathogens. Experts assert that this water is often cleaner than some conventional sources.

Notably, advanced purification is significantly more efficient in water conservation compared to household use, where standard practices can waste four to five gallons per gallon consumed, according to Bryan Cassens, Scottsdale’s director of water reclamation services.

With a focus on safety, the new regulations ensure rigorous, real-time monitoring at purification facilities. Continuous testing, with data reported every 15 minutes, forms the backbone of these standards. Inspections by ADEQ will further uphold compliance.

“We accomplish oversight in several ways,” Matas explained, noting both data monitoring and frequent facility inspections. While the ADEQ sets overarching standards, it allows cities the flexibility to design their systems.

Cities like Phoenix, Scottsdale, and Tucson are already preparing to incorporate advanced purified water into their systems. Scottsdale has been investigating this possibility since 2012 and aims to comply with the new standards by 2029. Cassens noted that approximately 85% of the water processed at Scottsdale’s facility is recovered and utilized.

Despite the efficiency of advanced purification, the process demands significant energy, particularly during the reverse osmosis stage. In response, Scottsdale has adopted energy conservation measures in collaboration with Arizona Public Service.

“Securing Scottsdale’s future water supply outstrips concerns over energy costs,” Cassens emphasized. He acknowledged the reality of diminishing water availability. “We must prepare for less.”

Advanced purification is viewed as a key component of a broader strategy for sustainable water management. Officials in Scottsdale advocate for a diversified water source approach. “Our intention is to blend this water with existing sources, including Central Arizona Project water,” stated Bryan Bouchard, a Scottsdale public information officer.

Phoenix is also advancing its capabilities, with plans for its first direct wastewater-to-drinking-water process slated for the Cave Creek reclamation plant, expected to be operational by 2030. Tucson is pursuing a similar initiative, aiming for a 2031 launch.

Matas indicated a growing interest in direct use among smaller municipalities, spurred by improved infrastructure and public confidence. For Bouchard, this initiative transcends immediate needs. “We’re shaping not just our future, but that of our children and grandchildren,” he concluded.