PHOENIX — As Arizona continues to grapple with water scarcity, cities are gaining a new option to supplement their supplies. New rules approved in March by the Arizona Department of Environmental Quality (ADEQ) now allow wastewater that has undergone advanced purification to be used directly as drinking water.
Previously, purified wastewater had to first be stored in aquifers or surface water before being re-treated and sent to homes. Under the updated regulations, cities can now treat wastewater through advanced purification and pipe it directly into municipal drinking water systems.
The process involves ultrafiltration, reverse osmosis, ultraviolet light disinfection and advanced oxidation to eliminate impurities and meet state drinking water standards. ADEQ officials say the result is water that’s cleaner than many traditional sources.
“This regulation creates a path for direct use while ensuring safety and transparency,” said Randy Matas, deputy director of ADEQ’s Water Quality Division. “Facilities must conduct real-time testing, with water quality reported every 15 minutes.”
Scottsdale, Phoenix and Tucson Leading the Way
Scottsdale has been researching direct reuse options since 2012 and plans to meet the new standards by 2029. Bryan Cassens, the city’s water reclamation director, said the treatment system is highly efficient, recovering about 85% of processed water. While energy-intensive, particularly during reverse osmosis, Scottsdale has partnered with APS to manage energy use.
“The expectation is that Arizona is going to get less than what it currently gets,” said Cassens. “We have to be prepared to deal with getting less water.”
Phoenix plans to launch its first direct reuse system by 2030 at the Cave Creek Water Reclamation Plant. Tucson has a similar facility in development, scheduled for completion in 2031.
Scottsdale spokesperson Bryan Bouchard emphasized that purified water will be blended with other sources like Central Arizona Project water to ensure consistent supply. “This isn’t just about now — it’s about the future of our kids and grandkids,” he said.
Oversight and Expansion
ADEQ will conduct regular inspections and monitor data from treatment facilities. While the agency sets the safety standards, it allows flexibility in how each city meets those requirements.
Experts expect smaller cities to adopt similar systems as infrastructure improves and public confidence grows. The goal is to create a diverse water portfolio that helps Arizona communities weather future supply reductions.
“All water is recycled,” Matas said. “This just makes that process more direct and sustainable.”
