Phoenix wastewater drinking water plant costs 300 million dollars and is half built, with tap water arriving by 2029

How the Phoenix wastewater drinking water plant works

The Phoenix wastewater drinking water plant taking shape north of the city is the Cave Creek Water Reclamation Plant, built around a process called direct potable reuse, meaning wastewater is treated until it is clean enough to drink and sent straight into the drinking water system, instead of first passing through a river or reservoir. Construction began in August 2024, and the City of Phoenix says the project reached about the halfway point in March 2026, marked by crews filling a 1 million gallon treatment basin. The 300 million dollar plant is designed to take in 8 million gallons a day of wastewater and turn it into 6.75 million gallons a day of drinking water, Assistant Water Services Director Nazario Prieto says.

We're talking receiving 8 million gallons per day of wastewater to produce 6.75 million gallons a day of potable water.

Nazario Prieto, Phoenix Assistant Water Services Director. Source 3.

The City of Phoenix states the finished plant will serve 25,000 households. The site has done this kind of work before. It ran as a recycled water plant producing nonpotable water, water clean enough for irrigation and industry but not for drinking, from 2000 to 2008, before closing.

Why Phoenix needs the water now

Record heat in March 2026 melted Rocky Mountain snowpack faster than usual, shrinking the water that feeds the Colorado River, the source the City of Phoenix relies on for much of its supply, ABC15 Arizona reports. Arizona faces cuts to its Colorado River water allocation as the shortage continues, and Prieto ties the new plant directly to those cuts.

Eventually, this program is going to offset some of those cuts.

Nazario Prieto, Phoenix Assistant Water Services Director. Source 4.

Arizona regulators have already written rules for this. The Arizona Department of Environmental Quality has written what the Arizona Municipal Water Users Association calls some of the most comprehensive direct potable reuse regulations in the nation, meaning the state, not just the city, has set safety rules for turning treated wastewater into drinking water.

When the water actually reaches the tap

The City of Phoenix own project page states the plant will feature advanced water purification and produce its purified water by 2027. That is not the same milestone as water flowing to a house. Reading that page alongside Prieto own account shows why. Once the purification equipment is running, the city holds the treated water for a required 1 year demonstration period before any of it enters the water system that reaches customers. Prieto states the plant is expected to be fully operational, meaning cleared for direct potable reuse, by 2029, which lines up with equipment turning on in 2027 followed by the year long demonstration period plus additional testing time.

Phoenix is not the first place to try this. Orange County, California, already produces up to 130 million gallons of purified drinking water a day for nearly 1 million residents, and Singapore meets nearly 40% of its national water demand with its own recycled water program called NEWater, the Arizona Municipal Water Users Association states. Phoenix already depends on rivers for about 98% of its water supply and already recycles 97% of the 70 billion gallons of wastewater it generates each year for nonpotable uses, so this project is adding drinking water to a system it already runs at large scale.