Advanced Water Purification: Creating Arizona's Next Water Supply

Arizona communities have spent decades showing that we can thrive in the desert by making every drop of water count. To do so, cities have invested in conservation programs, infrastructure upgrades, groundwater storage, and water recycling, while residents have reduced water use. These efforts have helped Arizona communities grow while using water more efficiently than ever.

As Colorado River supplies become increasingly uncertain, conservation alone cannot solve every challenge. While continuing to conserve, communities must also develop new, dependable local water sources to replace reduced Colorado River water supplies and avoid relying solely on groundwater pumping. One of the most promising tools available today is Advanced Water Purification (AWP).

Understanding Advanced Water Purification

Advanced Water Purification (AWP) is a safe and reliable near-term option we have to maximize our water portfolios and add resiliency — and perhaps one of the most misunderstood.

AWP is a proven process that further purifies highly treated recycled water using multiple layers of advanced treatment technology. The result is exceptionally high-quality water that meets or exceeds stringent federal and state drinking water standards.

While some view AWP as a new concept, communities around the world have safely used similar technologies for decades. Orange County, California, operates one of the largest advanced water purification systems in the world, producing up to 130 million gallons of purified water daily and supplying drinking water to nearly 1 million residents. Singapore has built purified recycled water — locally called NEWater — into a cornerstone of its national water strategy, with five facilities now meeting nearly 40 percent of the country's water demand. Even NASA uses advanced water recycling technology in space.

Nature Recycles Water. Advanced Water Purification Accelerates the Process.

Every drop of water on Earth has been recycled countless times through nature's water cycle. Water evaporates, condenses, falls as rain or snow, flows through rivers and groundwater systems, and is used again.

Advanced Water Purification follows the same basic principle, using technology to speed up and carefully control the process. Rather than relying solely on natural filtration, purified water passes through multiple treatment barriers, including microfiltration, reverse osmosis, and advanced oxidation. Each step removes different types of contaminants and provides additional protection.

More Testing, Not Less. Safety Through Multiple Layers of Protection.

One of the most common misconceptions about AWP is the phrase "toilet-to-tap." While memorable, it does not accurately describe how the process works.

Water does not move directly from a drain to a drinking water system. Instead, like all sources of water, it undergoes extensive treatment and testing throughout purification. Advanced Water Purification facilities are designed around a multi-barrier approach — each treatment step provides its own level of protection, and operators continuously monitor water quality throughout the process. If performance standards are not met, the system is designed to respond immediately.

The result is water that is subject to more rigorous testing and monitoring requirements than virtually any other water supply available.

Rigorous State Oversight and Regulation Ensure Safety

Advanced Water Purification facilities are subject to extensive regulatory oversight and monitoring.

In Arizona, the Arizona Department of Environmental Quality (ADEQ) developed some of the nation's most comprehensive direct potable reuse regulations. These regulations were adopted following years of scientific review, technical evaluation, stakeholder engagement, and collaboration among water providers, public health experts, regulators, and industry professionals.

Before purified water can enter a drinking water system, facilities must demonstrate they can consistently meet stringent treatment and operational requirements. The regulations require multiple treatment barriers, continuous monitoring, detailed reporting, and extensive safeguards to protect public health. Arizona's regulatory framework ensures that advanced purified water meets or exceeds all applicable drinking water standards before it reaches customers.

Why Arizona Communities Are Investing in AWP

The greatest benefit of Advanced Water Purification is not just that it produces clean water. It creates a new local water supply.

Unlike external water supplies that depend on river conditions, snowpack, or interstate negotiations, purified water starts with a resource communities already have: the water that flows through their existing wastewater treatment systems. That makes AWP an important tool for improving water reliability and resilience in the face of long-term drought and uncertainty around the Colorado River.

Across Arizona, communities are investing in projects to capture more value from every drop of water they already use. In Phoenix, construction is underway on the city's first Advanced Water Purification facility at the Cave Creek Road Water Reclamation Plant. It is expected to produce up to 5 million gallons of purified water per day when it comes online — enough to serve tens of thousands of households. Additional projects are being developed in North Phoenix and through regional partnerships to help create future water supplies for Valley communities.

Looking Ahead

Arizona has always succeeded by planning ahead.

Advanced Water Purification represents another example of that approach. It is a proven technology, backed by decades of successful operation, rigorous testing, and extensive oversight. Most importantly, it helps create a safe, reliable and locally controlled water supply that can support communities for generations to come.

As Arizona continues adapting to changing water conditions, Advanced Water Purification will play an increasingly important role in protecting our water future.

For 57 years, the Arizona Municipal Water Users Association has worked to protect our member cities' ability to provide assured, safe, and sustainable water supplies to their communities — Avondale, Chandler, Gilbert, Glendale, Goodyear, Mesa, Peoria, Phoenix, Scottsdale, and Tempe. For more information, visit amwua.org.

This article was featured on KTAR's website as part of AMWUA’s Water Watch partnership.