Legal Alert: The Superior Court granted Home Builders Association of Central Arizona motion for summary judgment in the homebuilders’ lawsuit against Arizona Department of Water Resources on April 21st, 2026. This could potentially provide a path forward for residential development on groundwater in the Valley.
The Challenged “Rules”
In November 2024, ADWR released an updated groundwater model for the Phoenix AMA. Based on this model, ADWR shifted from site-specific assessments to two new “AMA-Wide” standards. HBACA challenged the following two applications of the Phoenix AMA model:
- AMA-Wide Unmet Demand Rule: If modeling predicts that even a single well in the Phoenix AMA cannot meet its demand within 100 years, ADWR concludes that groundwater is not physically available anywhere in the domain.
- AMA-Wide Depth-to-Water Rule: If modeling predicts that the depth-to-water will exceed 1,000 feet at any location in the domain within 100 years, groundwater is deemed unavailable for the entire area.
The Court’s Findings
The court determined these standards are “rules” under the APA and that ADWR had not followed the proper promulgation procedures. The ruling notes that agencies cannot “camouflage” new rules as old ones to avoid statutory limits.
Final Order
Accordingly, Judge Blaney granted summary judgment in favor of HBACA, declaring both the Unmet Demand Rule and the Depth-to-Water Rule invalid. ADWR is enjoined from relying on these rules when reviewing or adjudicating applications for water supply certificates.
Next Steps
HBACA has until May 8 to prepare and lodge a formal form of Judgment. ADWR then has 20 days to file any objections. ADWR also has the right to appeal and to request a stay of judgment under ARCP 62.
At Gammage & Burnham, our Water Law attorneys bring a distinguished depth of experience and insight to one of Arizona’s most complex and consequential issues. Positioned at the forefront of this evolving area, our team is committed to guiding both businesses and residential developers through the legal and regulatory landscape shaping the future of water rights in Arizona.
Learn more about our Water Law Practice Group by clicking the link below: https://www.gblaw.com/practice-areas/water-law/
Learn more about our Water Law Attorneys by clicking the links below:
Grady Gammage Jr. https://www.gblaw.com/professional/grady-gammage-jr/
Michael J. Pearce https://www.gblaw.com/professional/michael-j-pearce/
Alexandra M. Arboleda https://www.gblaw.com/professional/alexandra-m-arboleda/
Kyle R. Stenseth https://www.gblaw.com/professional/kyle-r-stenseth/
Sean F. Krieg https://www.gblaw.com/professional/sean-f-krieg/
