Arizona Blocks New Homes in Greater Phoenix Due to Lack of Water

Greater Phoenix, the region with the fastest population growth in the US, is confronting a reckoning that will block future growth: Arizona has determined that there isn’t enough groundwater left in the region for all of the already approved housing projects under development.

State officials are moving to stop developers without approvals from building some new subdivisions, a clear signal that the era of explosive growth in Greater Phoenix is coming to an end, the New York Times reported.

The state said it would not issue new permits for home construction in parts of Maricopa County where homes rely on well water—which includes most of the area in the surrounding desert where the suburbs of Phoenix—with a population approaching 5M—have rapidly been expanding.

The state said it would not revoke building permits that already have been issued in Phoenix because Arizona is counting on new water conservation measures and “alternative sources” to produce the water necessary for housing developments that already have been approved.

According to Arizona’s state water agency, construction permits have been issued for about 80,000 new housing lots that have yet to be built in Greater Phoenix.

Gov. Katie Hobbs said at a news conference last week that Arizona was not immediately running dry, declaring that new construction would continue in Phoenix. “We’re going to manage this situation,” the governor said. “We are not out of water and we will not be running out of water.”

In areas relying on groundwater, Arizona’s action has set off an urgent race among housing developers to arrange alternative sources of water, including negotiating with farmers and Native American tribes for their share of river water, the NY Times reported.

Their options are limited because the water supply in Greater Phoenix is being squeezed from two directions: last month, Arizona joined California and Nevada in agreeing to a federal plan to reduce the amount of water they draw annually from the Colorado River by nearly a third.

Earlier this year, the Feds told the Colorado River basin states they needed to enact a new water allocation plan to avoid a doomsday scenario: low water levels at the Lake Mead and Lake Powell reservoirs would force the closure of dams, cutting off the water supply for 40M people.

The municipal water system in Phoenix relies on aqueducts linked to the Colorado River—only about 2% of the city’s water comes from wells. Phoenix already is using an estimated 2.2B gallons per day, twice as much water as the amount consumed daily by New York City.

Hobbs earlier this year released a state survey that projected groundwater resources for the next 100 years in Arizona. The survey showed that a combination of drought, overuse and climate change already have exhausted several groundwater sub-basins in Greater Phoenix.

While Hobbs expressed optimism that Arizona could manage the water problem in the short term, the state’s 100-year survey is based on a metric that’s already flawed: an assumption that the amount of water Arizona takes from the Colorado River would be constant for the next century.

According to the Kyl Center for Water Policy at Arizona State University, demand for groundwater is outpacing the state’s conservation efforts, with expanding industrial as well as residential developments rapidly depleting groundwater resources.