State engineer briefs Senate Natural Resources on Nevada's groundwater challenges and process for reviewing water-rights bills

Adam Sullivan, state engineer and principal administrator of the Division of Water Resources, told the Senate Committee on Natural Resources that Nevada is the "driest state in the nation" and that most municipal and irrigation supplies come from surface water while roughly one-third of the state's supply is groundwater. "Water use by volume is primarily used for irrigation — about 70% for irrigation, 10% for municipal and 10% for mining," Sullivan said.

Sullivan said groundwater administration presents the Division's greatest challenges because "the data are limited" and it is harder to understand long-term groundwater availability. He told the committee the Division receives about "a thousand water right applications per year" and that the office was created in 1903 to quantify water rights and to establish a procedure for appropriating new water rights.

The nut of Sullivan's presentation was that Nevada's existing appropriations exceed estimated long-term supply in many places and that resolving remaining questions depends on better data and careful statutory implementation. "Water rights that are already appropriated across most of the state exceed what we estimate as the long-term water supply," he said. He urged lawmakers to rely on updated science, including work being done through the Nevada Water Initiative, to inform policy decisions.

Sullivan reviewed core legal principles governing the Division's daily work: the prior-appropriation doctrine ("first in time, first in right"), beneficial use as both the measure and limit of rights, and the forfeiture rule often summarized as "use it or lose it." He emphasized that water rights are a right to use public water rather than private ownership of water and that rights remain tied to beneficial use.

Sullivan outlined long-term pressures: continuing population growth and economic development that increase demand; a legacy of appropriations that exceed sustainable supply in many basins; chronic groundwater-level declines in some areas; and the lack of new water to appropriate. He warned that ad hoc exceptions to foundational water-law principles can slow Division work and create perceptions of arbitrary decision-making.

On administration and planning, Sullivan said the Division is modernizing processes and building capacity: the 2023 Legislature funded 10 new positions and those positions "have all been filled," which he said is helping to chip away at backlog though training and institutional knowledge take time. He described the Nevada Water Initiative as a key effort to update baseline science, including recharge and connectivity estimates, and mentioned an initiative event slated for March 27 to present that work.

Sullivan closed by describing how the Division evaluates proposed statutory changes: does the proposal uphold basic principles of Nevada water law; will it protect aquifers and existing users; is the proposal a narrow fix tailored to a specific area; can the underlying issue be resolved within the existing statutory framework; and what are the implications for Division workload and cost. "When I testify on a bill, this is where I'm coming from," he said.

The committee followed the presentation with questions about mountain recharge and data updates. Sullivan said those are a priority of the Nevada Water Initiative and that newer methods and additional data collection are improving the Division's ability to quantify mountain recharge, discharge, consumptive use and inter-basin connectivity.

The presentation provided background material the committee said would inform consideration of two bills that followed the overview: SB31 (adjudication of vested water rights) and SB36 (groundwater conservation/voluntary retirement of groundwater rights).