Arizona says developers don't have enough groundwater to build in desert west of Phoenix

home is being built in in Rio Verde Foothills, Arizona, U.S. on January 7, 2023.

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Developers planning to build homes in the desert west of Phoenix don’t have enough groundwater supplies to move forward with their plans, a state modeling report found. 

Plans to construct homes west of the White Tank Mountains will require alternative sources of water to proceed as the state grapples with a historic megadrought and water shortages, according to the report.

Water sources are dwindling across the Western United States and mounting restrictions on the Colorado River are affecting all sectors of the economy, including homebuilding. But amid a nationwide housing shortage, developers are bombarding Arizona with plans to build homes even as water shortages worsen.

The Arizona Department of Water Resources reported that the Lower Hassayampa sub-basin that encompasses the far West Valley of Phoenix is projected to have a total unmet demand of 4.4 million acre-feet of water over a 100-year period. The department therefore can’t move to approve the development of subdivisions solely dependent on groundwater.

“We must talk about the challenge of our time: Arizona’s decades-long drought, over usage of the Colorado River, and the combined ramifications on our water supply, our forests, and our communities,” Gov. Katie Hobbs said in a statement last week. 

Developers in the Phoenix area are required to get state certificates proving that they have 100 years’ worth of water supplies in the ground over which they’re building before they’re approved to construct any properties. 

The megadrought has generated the driest two decades in the West in at least 1,200 years, and human-caused climate change has helped to fuel the conditions. Arizona has experienced cuts to its Colorado River water allocation and now must curb 21% of its water usage from the river, or roughly 592,000 acre-feet each year, an amount that would supply more than 2 million Arizona households annually. 

Despite warnings that there isn’t enough water to sustain growth in development, some Arizona developers have argued that they can work around diminishing water supplies, saying new homes will have low flow fixtures, drip irrigation, desert landscaping and other drought-friendly measures. More than two dozen housing developments are in the works around Phoenix.

Rising Risks: Building through the great western drought