STATE CAPITOL, PHOENIX – Republican members of the Arizona State Legislature are seeking answers to basic questions regarding Arizona’s groundwater supply such as “How much water do we have?”

In a letter sent to the Arizona Department of Water Resources (ADWR) on December 23, 2024, Representative Gail Griffin, Senator Tim Dunn, and former Senator Sine Kerr asked the agency to provide basic information on the following details related to Arizona’s rural groundwater basins:

1. The average depth-to-water level in each basin.
2. The maximum depth of each basin.
3. The average depth of each basin.
4. The total volume of groundwater in each basin.
5. The number of index wells in each basin.

A copy of the letter can be found here, which also requested the Department’s sources and assumptions. 

According to Representative Griffin, the request is needed because state and local officials currently do not have this information. In 2022, as a part of the major Water Infrastructure Finance Authority (WIFA) overhaul, the state passed legislation requiring the director of ADWR to conduct a recurring “Supply and Demand Assessment” for each of Arizona’s fifty-one rural groundwater basins every five years. See ARS 45-105(B)(14).

“The intent was to give Arizonans a better understanding of the groundwater supply beneath their feet,” said Representative Griffin. “For the last two years however, none of the Department’s assessments have included this basic information—such as ‘how much water do we have’ and ‘how long will that water last.’ This information is a fundamental component of the ‘supply’ side of the ‘supply and demand’ equation and needs to be included in each of the Department’s five-year ‘Supply and Demand’ Assessments.”

Copies of the Department’s Supply and Demand Assessments can be found here. Representative Griffin encourages members of the public to review any of the 21 assessments that have been issued to-date.

During a Special Meeting of the House Committee on Natural Resources, Energy & Water (NREW) on February 20, 2025, the Department stated that the recurring 5-year Supply and Demand Assessments are intended to be like “water budgets,” showing the amount of water that is going in and coming out of a basin each year.

When asked by Representative Teresa Martinez, however, “How much [water] do we currently have in our ‘bank account’,” the Department did not provide an answer.

“What good is a ‘water budget’ if we don’t know how much is in our ‘bank account’?” asked Representative Griffin.

On January 7, 2025, the Department provided a preliminary response to the December 23 letter, stating the number of active index wells in each basin and the maximum depth of each basin at its deepest point. A copy of the Department’s response can be found here.

According to the Department’s preliminary response, the Willcox and Gila Bend groundwater basins are 4,800 feet deep at their deepest points, but the Department has yet to provide the total amount of groundwater that is available to each of these depths.

Representative Griffin notes that the depth to bedrock in each groundwater basin is not even across the entire basin, resulting in some areas that are deeper than others and some places that are seeing declines while other areas where water levels are increasing.

“Just because you drill a well does not guarantee that there will be one hundred years’ worth of water,” said Representative Griffin.

“Republicans and Democrats both agree we need to know how much water is available in order to make informed decisions on critical groundwater policy,” said Representative Griffin. “It’s also essential to our ability to plan for the future. How are we supposed to plan if we don’t know how much water we have?”

To address the lack of complete information, Representative Griffin has introduced legislation—HB2271 (supply and demand; assessment; groundwater)—to update the 5-year Supply and Demand Assessment statute and require the Department to include this information in its reports, moving forward.

If adopted, the bill would provide critical answers to these basic questions, such as, “How much water do we have?” and “How many years will that water last at the current rate of decline?” With this information, lawmakers can plan to add new tools that work for rural Arizona, such as groundwater recharge, replenishment, and reuse.

“We understand that additional steps may be necessary to gather this information, but we also believe that taking these steps is necessity to do our jobs effectively,” said Representative Griffin. “I think the Department wants to make decisions based on science and that, if we give it the time and opportunity to gather this information, it will result in a better and more constructive dialogue for everyone.”

The bill advanced out of the House NREW Committee last week on a party-line vote. The bill received support from Pinal County Supervisor Stephen Miller and a ‘thumbs up’ from former Democrat lawmaker Tom Prezelski.

HB2271 passed the House on Wednesday and now advances to the Senate for consideration.

Gail Griffin is a Republican member of the Arizona House of Representatives serving Legislative District 19, which includes areas of Greenlee, Graham, Cochise, and eastern Pima and Santa Cruz Counties. She also serves as Chairman of the House Natural Resources, Energy & Water Committee.