A decade after Arizona rejected local farmers’ effort to rein in agricultural development they feared would drain the San Simon Valley’s groundwater supply, applications for large-scale wells have surged, and the region’s already strained aquifer is being depleted faster than it can recover.
Since farmers first petitioned the state for groundwater protections in 2015, landowners or companies tied to them have submitted 154 applications for high-capacity wells in the southeastern Arizona sub-basin. That’s more than were filed over the preceding 35 years combined, according to an AZCIR analysis of state records.
Water officials estimate the sub-basin is losing about 50,000 acre-feet more groundwater than is naturally replenished each year—roughly the amount used by 150,000 Arizona homes. Overpumping has permanently reduced the aquifer’s ability to store water, and parts of the valley are sinking.
Now, local farmers are trying again to protect what’s left of San Simon’s groundwater supply. In September, the Arizona Department of Water Resources formally acknowledged their petition for an Irrigation Non-Expansion Area, or INA, opening the door to a permanent ban on irrigating new farmland.
The spike in San Simon well applications reflects a trend AZCIR has documented before: As Arizona restricts groundwater pumping in some areas, investors look to others with fewer limits. In southeastern Arizona, the Douglas basin adopted stricter controls in 2022, followed by the Willcox basin in 2025.
“Now, we’re the only place that’s unregulated down here with agricultural potential,” said local farmer Mark Cook, one of the lead INA petitioners.
But a legal challenge to similar groundwater restrictions elsewhere in Arizona could jeopardize the farmers’ latest effort.
In January, a Maricopa County Superior Court judge sided with two out-of-state investors who argued that ADWR improperly established an INA in Mohave County’s Hualapai basin. If upheld, the ruling could force the agency to follow a lengthier process for establishing INAs statewide, including in San Simon. The agency appealed, and a decision is pending.
The San Simon petition has already triggered a temporary ban on irrigating land that has not been irrigated in the past five years. But those restrictions could disappear if the petition fails or the court invalidates the state’s INA process. Landowners can still apply for new wells in the meantime, potentially allowing them to move quickly if the ban is lifted.
Ten applications for large-scale wells were filed in August 2025 alone as petitioners gathered support, AZCIR’s analysis found. Another 10 followed between the January ruling in the Hualapai case and ADWR’s acknowledgment of the San Simon petition in September.
“This is what happens all the time,” said Paul Hirt, an Arizona State University professor emeritus and San Simon sub-basin resident who has studied and worked on water policy in the American West for decades.
“Every single time the department talks about establishing (these types of restrictions), there’s a whole bunch of people scrambling to try to get their hat in the ring before the decision is made.”
Cook, a lead petitioner on both INA efforts, comes from a family that has farmed in southeastern Arizona for generations. He grew up in nearby Willcox.
After some time out of state, he returned to the region in 1999 to find that its once-vibrant cotton industry was mostly gone. Groundwater levels had fallen so far that pumping water for cotton was no longer economical. What remained, he said, were higher-value crops like pecans and pistachios that could justify the higher pumping costs.
When Cook started planting near Bowie, there were only four or five other farmers in the area, so it was relatively easy to informally limit expansion and pumping, he said. When he and his partners bought land to expand their operations, they planted less than half of it, intentionally leaving the rest unfarmed.
But as nut prices increased around 2015, growers from places like California—where sweeping groundwater regulations had been approved the previous year—started looking to Arizona’s largely unregulated basins for places to expand.
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Cook underestimated how attractive even less desirable farmland would become to growers, even as one of his partners urged him to buy certain parcels to keep them from being planted.
“I told him: ‘No, no, no, there’s no way anyone in their right mind would buy that and plant it,” he recalled. “‘Anyone that’s going to make that kind of capital investment is going to do their homework.’”
“Well, he was right, and I was wrong,” he said.
That same year, Cook and other farmers filed their first INA petition, seeking to prevent further agricultural development and the additional groundwater pumping they believed would follow. The move was not well-received, with some landowners accusing them of trying to shut out competitors.
“This petition isn’t about water shortage. It’s about a premeditated land-take,” local farm owner Lisa Chima said at a 2015 town hall meeting.
Other landowners worried that an INA would upend plans to farm their land after retiring. One said he’d spent his life savings on land that he likely couldn’t afford to irrigate fast enough to qualify for water rights under an INA.
ADWR ultimately denied the petition, which failed again on appeal. Much of the depletion Cook and his partners feared had not yet occurred—the young nut trees were still using far less water than they would once mature. And under state law, ADWR could not consider that expected future pumping when deciding whether the aquifer qualified for protection.
Over the next decade, the trees grew larger and new agricultural development continued. The strain on San Simon’s aquifer became increasingly evident.
As neighboring Douglas and Willcox adopted stricter groundwater controls unavailable to sub-basins like San Simon under state law, the valley became one of the few places in southeastern Arizona with scant limits on agricultural expansion and conditions attractive to growers.
“That, in particular, really put the squeeze on us,” Cook said.
A similar pattern played out in northwest Arizona’s Hualapai basin, where AZCIR documented an influx of out-of-state investors and industrial-scale farms that took control of 99% of the basin’s agricultural land starting in 2014. It took two attempts to establish an INA there, and the pending lawsuit could still invalidate it.
“It’s a major vulnerability,” especially in rural Arizona, said Christopher Kuzdas, Water Program director for the Environmental Defense Fund, a nonprofit advocacy group. “(Outside interests) can just show up, sink a well, and take as much as they want for whatever they want.”
Beyond the 154 applications for new wells in San Simon, state records reviewed by AZCIR show that existing wells changed hands as large-scale operations moved into the valley. While records indicate many of those wells remain capped, they could be used again.
Companies tied to Diamond Nut from California’s Central Valley took over 53 wells just three months after the INA was rejected on appeal in 2015, AZCIR found, making the out-of-state company one of the valley’s largest well-owners alongside Cook and his partners.
Since then, the California companies have drilled at least 24 more wells with an average depth of about 1,200 feet, according to ADWR data. Some can pump up to 2,000 gallons per minute.
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New wells are also reaching into the valley’s lower aquifer, which used to flow naturally to the surface. ADWR predicts that portions of the upper aquifer, which residents have historically relied upon, will be depleted in less than a century.
An August report by ADWR’s chief hydrologist found that groundwater levels have been declining for decades, with losses accelerating alongside increased agricultural activity. San Simon’s groundwater deficit is already larger than those that prompted the recent restrictions in the Hualapai and Douglas basins.
The effects are visible above ground, too. As groundwater is pumped out, underground sediment can compress, causing the land above it to sink. Parts of the San Simon sub-basin have sunk nearly seven feet since 1996, according to the ADWR report.
That underground compression can permanently reduce the aquifer’s ability to store water, even if groundwater levels eventually recover. The sinking ground can also split open, creating cracks known as fissures that can damage roads, buildings and other infrastructure. The Arizona Geological Survey has mapped approximately 26 miles of those fissures in the area.
By 2025, even a longtime opponent of expanded groundwater regulation was acknowledging the growing pressure on San Simon’s water supply.
State Rep. Gail Griffin, who had blocked previous attempts at groundwater regulation, backed legislation that would have allowed San Simon residents to vote to establish an INA. The Hereford Republican said during a legislative hearing that the measure was needed to “stop the bleeding.”
But the bill would also have eliminated some water-use reporting requirements and added new complications to the existing regulatory process. Gov. Katie Hobbs’ office said the legislation was full of “poison pills” that would have weakened the state’s already limited INA protections.
Some San Simon residents who wanted stronger groundwater regulation opposed the bill for the same reason. Hirt, the ASU professor emeritus and water policy expert, joined other sub-basin residents in urging Hobbs to veto the measure.
“It’s appalling to us that we have waited a decade for the Legislature to finally acknowledge that something needs to be done, and now the proposed solution is an inadequate partial INA,” the residents wrote. “It’s unacceptable.”
Hobbs vetoed the measure soon after, accusing lawmakers of using it as “political cover” after years of failing to enact broader groundwater reform. With no other regulatory option available, Cook and his partners returned to the same tool they’d sought in 2015, believing a decade of additional data would make an INA petition harder to reject.
Their renewed effort faces some of the same opposition, including from Silverado Farms, whose owner, Lisa Chima, spoke out against the 2015 petition. Her husband, Geneal Chima, told AZCIR that the sub-basin still has enough water and does “not need any water restrictions or regulations.”
The new petition also moved slowly, with ADWR taking nearly a year to formally acknowledge it. Some of that time was spent determining whether the petition had enough eligible irrigators to proceed. But the Hualapai court fight also loomed over the process.
“It’s absolutely causing a delay,” said Kuzdas, whose organization backed the petitioners in an amicus brief in the Hualapai case. “And that delay is having a real impact in San Simon on the growers there.”
The timing matters because the INA process was designed to move relatively quickly. In court filings, ADWR argued that prolonged uncertainty over whether new land can be irrigated can itself create problems for farmers. If the appeals court finds Arizona’s current INA process invalid, the fate of San Simon’s pending petition will be unclear.
Even if the petition succeeds, an INA would not reduce the groundwater pumping already depleting the aquifer.
Near Portal and Paradise at the southern end of the sub-basin, concerns about household wells going dry—as they have in some neighboring basins—have prompted residents to begin discussing the possibility of an INA, Hirt said. But the area is less agricultural than northern San Simon, and some of those residents’ concerns fall outside what an INA can address.
“It’s really a tool for farmers to protect themselves from the next generation of farmers coming in and taking their water,” Hirt said.
Arizona offers another way to manage groundwater through Active Management Areas, which can impose broader limits on pumping. But AMAs cannot be established in individual sub-basins like San Simon—at least not without a change in state law.
For Cook, even the limited restrictions petitioners are seeking represent a difficult compromise.
“I’m a big private property rights guy myself, and none of us liked what the INA would do in that regard. But unfortunately, it was the only tool available to us,” Cook said.
“All we can do is keep it from getting worse.”
Christopher Lomahquahu contributed to this story.
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