Wastewater is becoming part of Phoenix’s water model as the city advances sustainable supply strategies.
Key Points
• Phoenix is converting wastewater into drinking water.
• The effort aims to reduce reliance on the Colorado River.
• The initiative strengthens long-term water supply.
PHOENIX — In a desert metropolis where water has long dictated survival and growth, Phoenix is advancing a strategy that reimagines one of its most overlooked resources: wastewater.
Facing prolonged drought, increasing pressure on the Colorado River and continued population growth, the city is investing in advanced water purification technology to convert treated wastewater into drinking water. The approach reflects a broader shift across the American West, where utilities are turning to reuse as a way to stretch limited supplies.
Phoenix officials consider the initiative critical to the city’s future, according to Nazario Prieto, assistant water services director for the city, who said reduced supplies from the Colorado River could lead to significant cuts and that the purification program is intended to help make up for some of those losses over time.
The initiative, known as Pure Water Phoenix, is designed to take treated wastewater and subject it to multiple layers of purification, including ultrafiltration, reverse osmosis and ultraviolet advanced oxidation. These processes remove solids, pathogens, dissolved salts and trace contaminants, producing water that meets or exceeds federal and state drinking standards.
The purified water is initially mineral-free and requires the reintroduction of essential minerals before distribution.
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Water reuse: a response to desert scarcity
Phoenix’s current water system relies heavily on surface supplies from the Colorado, Salt and Verde rivers. City data shows roughly 98% of its water historically comes from these sources, leaving the region vulnerable to long-term shortages as drought conditions persist and demand grows.
The move toward water reuse echoes a much older tradition. Long before modern Phoenix emerged, the Hohokam people engineered an extensive canal system across the Salt River Valley, sustaining agriculture in an arid environment through careful water management.
From wastewater to drinking water: Phoenix’s supply strategy
Phoenix plans three advanced water purification facilities as part of its long-term water strategy, with major milestones extending into the next decade. Together, the projects are expected to add millions of gallons of purified water per day to the city’s supply portfolio while reducing dependence on imported sources.
The first of those projects is underway in north Phoenix at the Cave Creek Water Reclamation Plant, where a previously shuttered facility is being redeveloped into a next-generation treatment site. The upgraded plant will use advanced purification processes to convert recycled water into drinking water.
When fully operational, the Cave Creek facility is expected to produce nearly 7 million gallons of purified drinking water per day — enough to serve about 25,000 households — with the ability to expand capacity in the future as demand increases.
During a construction milestone this week, crews conducted a test fill of a treatment basin capable of holding approximately 1 million gallons of water, evaluating system performance as part of ongoing development.
The Cave Creek project will begin with indirect potable reuse, in which purified water is returned to groundwater supplies or reservoirs before undergoing final treatment and distribution. Arizona regulators have expanded rules in recent years to allow for both indirect and direct potable reuse, providing cities with more flexibility to adopt advanced purification systems.
Two additional facilities are planned. The North Gateway Advanced Water Purification Facility in north Phoenix is supported by $179 million in federal funding and will further expand the city’s capacity to recycle wastewater into drinking water.
A third, larger project is planned at the 91st Avenue wastewater treatment plant in the West Valley, where expanded purification capacity is expected to play a significant role in the city’s long-term water supply strategy.
Challenges, public perception and the path forward
Across Arizona and the broader Southwest, other cities are pursuing similar approaches. Tucson is advancing its own advanced water purification system to convert wastewater into drinking water, while Scottsdale has used public outreach — including partnerships with breweries — to build acceptance of recycled water.
Supporters say advanced water purification offers a locally controlled, sustainable solution that reduces reliance on distant water sources and creates a more resilient, closed-loop system. Challenges remain, including public perception, high upfront costs and the need for continuous monitoring to ensure water quality.
For Phoenix, the stakes are tied not only to environmental pressures but also to economic stability. Reliable water supplies underpin housing development, industrial expansion and long-term planning in one of the nation’s fastest-growing metropolitan areas.
As construction progresses at Cave Creek and additional facilities move forward, the city is betting that its future will depend less on securing new water sources and more on reusing the ones it already has — transforming wastewater into a renewable supply, one gallon at a time.
© 2026, Eduardo Barraza. All rights reserved.
