Groundwater serves as a vital source of drinking water and supports ecosystems, agriculture, and industrial needs. A wave of recent court rulings has bolstered the authority of states to protect invaluable groundwater resources as levels have declined significantly around the country in the last several decades. Recognizing its significance, courts in Idaho, Nevada, and Montana made consequential decisions that strengthen state-level control and oversight over groundwater protection.

Idaho currently holds the unenviable distinction of having the highest rate of groundwater depletion in the entire country, according to a New York Times investigation, primarily due to over-pumping to maintain irrigation for agriculture. However, a recent court ruling has affirmed Idaho's authority to regulate groundwater use and ensure its sustainable management. The decision allows the director of the Idaho Department of Water Resources, “to initiate administrative proceedings to curtail the withdrawal of water from any well during any period where water to fill a water right in said well was not available.”[1] This ruling also allows the state to address concerns of depletion by establishing limits on groundwater allocation, implementing permitting systems, and enforcing regulations to prevent excessive pumping and combat depletion.

In Nevada, a recent ruling affirmed the state’s sovereignty over its groundwater resources. After years of declining groundwater levels resulting from the combined impacts of drought, population growth, and land development, the state implemented pumping limits, which provoked a lawsuit filed by developers. The Nevada Supreme Court affirmed that the state possesses exclusive regulatory authority over groundwater, including the ability to determine groundwater rights, allocations, and usage. Further, this ruling reinforced that Nevada, as the rightful steward of its groundwater, has the power to enact regulations, establish management plans, and allocate water resources based on local conditions and demands, “using best available science.”[2]

Montana faced a similar depletion issue related to land development and the court ruled that, “state officials have failed to impose adequate limits on the construction of new homes that rely on groundwater.”[3] The court’s decision strengthened the state's oversight and control over groundwater resources and recognized that the state has the authority to regulate groundwater withdrawals and ensure their sustainable use. Additionally, the ruling determined that the Montana Department of Natural Resources and Conservation possesses the power to manage groundwater permits and impose conditions on water users to prevent negative impacts on existing rights or the environment.

These court rulings mark significant milestones in the protection of groundwater resources. By affirming and reinforcing state authority, the rulings provide a strong legal framework for effective and sustainable groundwater management to ensure water security for its communities and ecosystems into the future.

[1] “South Valley Ground Water v. Idaho Dept of Water Resources.” Justia Law, 12 Jan. 2024, law.justia.com/cases/idaho/supreme-court-civil/2024/49632.html.

[2] Solis, Jeniffer. “Impacts of Court Groundwater Decision Still a Long Way off, Top Water Regulator Tells Lawmakers.” Nevada Current, 4 Mar. 2024, nevadacurrent.com/2024/03/04/impacts-of-court-groundwater-decision-still-a-long-way-off-top-water-regulator-tells-lawmakers/.

[3] Flavelle, Christopher. “Montana Court Restricts Use of Groundwater for New Homes.” The New York Times, The New York Times, 16 Feb. 2024, www.nytimes.com/2024/02/16/climate/montana-court-groundwater-development.html.