Judicial Deference to the State Engineer’s NRS 533.380 Extension-of-Time Determinations When Supported by Substantial Evidence of Diligence Toward Full Perfection

1. Introduction

In THORSON, P.E. v. ESMERALDA MINERALS, LLC (Nev. Feb. 20, 2026), the Nevada Supreme Court reversed a district court order that had set aside the State Engineer’s grant of an extension of time (EOT) under NRS 533.380. The dispute arose in the Clayton Valley hydrographic basin (Esmeralda County), where Albemarle Corporation (a lithium operator that acquired the Silver Peak Lithium Operation) holds certificated and permitted groundwater rights totaling 20,000 acre-feet per annum (afa), including permits 52918 through 52921.

Respondents Esmeralda Minerals, LLC and its parent Pure Energy Minerals, Ltd. (collectively, “Pure Energy”)—entities with mining claims in the same basin—objected to Albemarle’s EOT requests, arguing that Albemarle was effectively speculating and “hoarding” water because the project historically used less water than the full permitted amount and allegedly could not physically reach full beneficial use.

After the district court remanded for an evidentiary hearing, the State Engineer conducted a four-day hearing and again granted Albemarle’s 2017 EOT (ultimately a one-year extension). The district court then granted judicial review again and ordered the State Engineer to reverse. The State Engineer and Albemarle appealed.

The central legal questions were: (1) whether the State Engineer applied the correct legal standard for an EOT (diligence toward perfecting the entire appropriation), and (2) whether substantial evidence supported the State Engineer’s findings such that the district court was required to defer rather than reweigh the record.

2. Summary of the Opinion

The Nevada Supreme Court held that the State Engineer applied the correct legal standard and that the EOT grant was supported by substantial evidence. The Court faulted the district court for placing “undue weight” on an isolated phrase (“some quantity of water”) while overlooking that, read as a whole, the State Engineer measured Albemarle’s showing against its obligation to put the full 20,000 afa to beneficial use.

On the evidentiary record, the Court emphasized the limited role of judicial review under NRS 533.450: the State Engineer’s decision is presumed correct; reviewing courts may not reweigh evidence, reassess credibility, or substitute their judgment where substantial evidence supports the agency’s factfinding. Because a reasonable mind could accept the evidence cited by the State Engineer as adequate, the Court ordered the district court’s judgment reversed.

3. Analysis

3.1 Precedents Cited

• Bacher v. Off. of State Eng’r of Nev. (2006)
  • Principle used: Beneficial use is a “fundamental requirement” of Nevada water law because water is “a precious and increasingly scarce resource.”
  • Standard of review: Substantial evidence is “that which a reasonable mind might accept as adequate to support a conclusion,” and courts may not substitute their judgment for the State Engineer’s or reweigh evidence/credibility.
  • Influence here: The Court relied on Bacher to (a) frame the EOT inquiry as ultimately tied to beneficial use, and (b) enforce strong appellate restraint once the State Engineer’s factual findings clear the substantial-evidence threshold.
• Desert Irrigation, Ltd. v. State (1997)
  • Principle used: An EOT applicant must show diligence toward perfecting the entire appropriation—not merely some portion of permitted water.
  • Influence here: The Court reaffirmed the “entire appropriation” requirement, but distinguished Desert Irrigation on its facts: unlike the rightsholder there (who failed to pursue perfection and later attempted to redirect rights to a separate, non-contiguous development), Albemarle’s record showed efforts aimed at expanding use within the existing operation toward full use.
• King v. St. Clatr (2018)
  • Principle used: On appeal, the Supreme Court performs the same review as the district court in judicial review of administrative decisions.
  • Influence here: This anchored the Court’s posture: it independently applied the administrative review framework (legal questions de novo; factual findings for substantial evidence) rather than deferring to the district court’s view.
• Pyramid Lake Paiute Tribe of Indians v. Ricci (2010)
  • Principle used: Questions of law—such as whether the State Engineer applied the correct legal standard—are reviewed de novo.
  • Influence here: The Court used de novo review to reject the district court’s conclusion that the State Engineer applied a “some quantity of water” standard, finding instead that the decision repeatedly referenced the statutory obligation to perfect the full appropriation.
• Wilson v. Pahrump Fair Water, LLC (2021)
  • Principles used: (a) deference to executive agencies’ specialized expertise; (b) heightened deference can be especially warranted in technically and scientifically complex water-rights determinations; (c) the State Engineer may draw inferences from expert evidence based on technical expertise.
  • Influence here: The Court invoked Pahrump Fair Water to justify deference to the State Engineer’s evaluation of competing expert opinions—including Pure Energy’s argument that full use was “impossible.”

3.2 Legal Reasoning

(A) The governing EOT standard under NRS 533.380

• Under NRS 533.380(1), an appropriator must timely show the water has been put to beneficial use.
• Under NRS 533.380(3), the State Engineer may grant EOTs for good cause if the applicant shows it is “proceeding in good faith and with reasonable diligence to perfect” the rights.
• Under NRS 533.380(6), “reasonable diligence” is the “steady application of effort” under all facts and circumstances, and work on one feature of an integrated system may count toward diligence for the whole.
• Consistent with Desert Irrigation, Ltd. v. State, diligence must be toward perfecting the entire appropriation, not merely a fraction.

(B) The Court’s correction of the district court’s “wrong legal standard” finding

• The district court focused on the State Engineer’s isolated phrase “some quantity of water” as evidence that the Engineer applied an impermissibly relaxed standard.
• On de novo review, the Supreme Court read the agency decision “in full” and concluded the State Engineer repeatedly measured Albemarle’s showing against the obligation “to put the full 20,000 (afa) to beneficial use.”
• The Court’s method is instructive: it treats “legal standard” review as a holistic inquiry into what the decision actually required and found, not a “gotcha” exercise based on stray language.

(C) Substantial evidence and the prohibition on reweighing

• The Court reaffirmed that under NRS 533.450(10) the State Engineer’s decision is presumed correct and the challenger bears the burden.
• The State Engineer cited evidence of Albemarle’s plan and progress toward full use: regulatory compliance efforts, infrastructure maintenance and efficiency improvements, increasing active wells, pursuit of a “super permit” (block permit) to expand wells/production, the effect of bureaucratic delays, and scientific studies to understand the groundwater system—paired with the technical complexity and operational environment of the site.
• The Court emphasized that the State Engineer may discount evidence (including expert testimony) as immaterial or unreliable and may choose among competing expert views—an especially salient point where Pure Energy argued “impossibility” of full beneficial use.
• Because a “reasonable mind” could accept the cited evidence as adequate, the Court held the substantial-evidence standard was satisfied and the district court erred by reaching the opposite conclusion.

(D) Why the one-year EOT mattered

The Court highlighted the State Engineer’s cautious approach: rather than granting the requested five-year EOT, the State Engineer granted only one year. This fact supported the reasonableness of the agency’s judgment and undercut the narrative that the decision amounted to unchecked speculation or hoarding.

3.3 Impact

• Reinforced deference in technically complex EOT disputes: The opinion strengthens the practical insulation of State Engineer factfinding where the record contains credible evidence of ongoing, project-oriented diligence—even when challengers present competing expert opinions.
• Holistic reading of agency decisions: Reviewing courts are cautioned against elevating isolated phrasing over the decision’s full articulation of the governing standard and findings.
• Project-development activities can constitute “diligence”: The Court’s acceptance of evidence such as regulatory compliance work, scientific studies, and infrastructure preparation signals that diligence is not limited to immediate pumping increases, particularly where an integrated system requires prerequisite steps.
• Litigation posture for objectors: Objectors seeking to overturn EOTs will likely need to target clear legal error, internal inconsistency, or a record so thin that no reasonable mind could find diligence—rather than urging courts to choose among permissible inferences.
• Administrative record strategy: Applicants may treat this decision as support for developing a detailed evidentiary narrative of “steady application of effort” (including staged expansion plans), anticipating that substantial evidence review is deferential once that narrative is documented.

4. Complex Concepts Simplified

• Beneficial use: The foundational requirement that water rights exist to the extent the water is actually used for a productive, legally recognized purpose—not merely claimed or held.
• Perfecting a water right: Completing the work and actual use needed to convert a permitted right into an exercised right within the permitted limits (e.g., the full 20,000 afa).
• Extension of time (EOT): Extra time granted by the State Engineer to finish development and demonstrate beneficial use, allowed when the applicant shows good faith and reasonable diligence.
• Reasonable diligence: Not “maximum speed,” but a steady, efficient effort under real-world constraints (engineering, regulatory approvals, operational complexity). Work on one part of an integrated project can count toward the whole.
• Substantial evidence: A low-to-moderate evidentiary threshold: enough relevant evidence that a reasonable person could agree with the agency. It does not require the “best” or “most” evidence.
• Arbitrary or capricious: A decision lacking a rational connection to the evidence or made without consideration of relevant factors. If substantial evidence supports the agency’s findings, overturning for arbitrariness is difficult.
• De novo review vs. deferential review: Courts review legal questions fresh (de novo), but they defer to the agency on factual findings if supported by substantial evidence.

5. Conclusion

This decision reasserts a clear rule for Nevada water-right administration: when the State Engineer applies the correct NRS 533.380 standard—diligence toward perfecting the entire appropriation—and substantial evidence supports the factual findings, courts may not overturn the EOT grant by reweighing the record or seizing on isolated language. The opinion situates EOT determinations within the State Engineer’s technical expertise and confirms that documented, project-wide efforts (including regulatory and scientific groundwork) can satisfy “reasonable diligence,” shaping how future applicants and objectors will build and attack EOT records under NRS 533.450.