Wyoming WAPA Review: Arbitrary-and-Capricious Scrutiny Applies to Agency Legislative (Rulemaking) Action

1. Introduction

These consolidated appeals concern Albany County’s 2023 amendments to its zoning regulations establishing and governing an Aquifer Protection Overlay Zone (APOZ) designed to protect the Casper Aquifer, a major drinking-water source east of Laramie. The appellants included (1) ranching/landholding entities (Warren Livestock, LLC, et al.) and (2) numerous individual property owners (Bienz et al.).

The central disputes were: whether the Board had statutory authority to enact aquifer-protection zoning (including a 35-acre minimum lot size); whether differing procedures for APOZ boundary changes violated Wyoming equal protection principles; what standard of judicial review applies under the Wyoming Administrative Procedure Act (WAPA) to “legislative” agency action; and whether the amendments were arbitrary or capricious.

The decision also operates as the “second chapter” of the litigation: in Bienz v. Bd. of Cnty. Comm'rs, Cnty. of Albany, 2024 WY 102 (“Bienz I”), the Court held the Board’s legislative zoning amendments are reviewable under WAPA notwithstanding their legislative character.

2. Summary of the Opinion

The Wyoming Supreme Court affirmed the district court’s ultimate approval of the APOZ amendments, but corrected the district court’s review framework. The Court held:

• Authority: The Board acted within its county zoning authority under Wyo. Stat. Ann. § 18-5-201(a) to protect public health, safety, and welfare by regulating land use for aquifer protection, and this did not conflict with WDEQ’s environmental authority.
• Equal protection: One equal protection theory was moot due to later amendments; the remaining claim failed rational-basis review because tailoring procedures for overlay-boundary changes is rationally related to the County’s legitimate interest in aquifer protection.
• Standard of review: WAPA’s arbitrary and capricious standard applies to agency legislative action (rulemaking-like action), and the district court erred in concluding otherwise.
• Merits: The 2023 amendments—including the 35-acre minimum lot size—were supported by a rational basis in the record and were not arbitrary, capricious, or contrary to law.

3. Analysis

3.1. Precedents Cited

A. Reviewability and the adjudicatory/legislative vocabulary

• Bienz v. Bd. of Cnty. Comm'rs, Cnty. of Albany, 2024 WY 102 (“Bienz I”): The foundation for reviewability. The Court reiterates that the “legislative” label does not bar WAPA review and uses Bienz I’s conceptual distinction between adjudicatory and legislative action as the baseline for this opinion’s standard-of-review discussion.
• Holding's Little Am. v. Bd. of Cnty. Comm'rs of Laramie Cnty., 670 P.2d 699: Quoted (via Bienz I) for the classic distinction: legislative action is prospective and general; adjudicatory action targets identifiable persons/situations.
• N. Laramie Range Found. v. Converse Cnty. Bd. of Cnty. Comm'rs, 2012 WY 158: Used to explain the difference between formal trial-type contested cases and informal proceedings, and to support using arbitrary/capricious review where proceedings are not trial-type.

B. County powers, zoning breadth, and limits

• Bd. of Trs. of Laramie Cnty. v. Bd. of Cnty. Comm'rs of Laramie Cnty., 2020 WY 41; Bd. of Cnty. Comm'rs for Sublette Cnty. v. Exxon Mobil Corp., 2002 WY 151; Seherr-Thoss v. Teton Cnty. Bd. of Cnty. Comm'rs, 2014 WY 82; Ford v. Bd. of Cnty. Comm'rs of Converse Cnty., 924 P.2d 91; Carter v. Bd. of Cnty. Comm'rs of Laramie Cnty., 518 P.2d 142: These cases supply the governing “Dillon’s Rule” style framework: counties possess only powers expressly granted or necessarily implied; doubts resolve against the county.
• Schoeller v. Bd. of Cnty. Comm'rs of Park Cnty., 568 P.2d 869: Quoted for the “express powers + implied power to make the express power meaningful” concept in zoning.
• Wilson Advisory Comm. v. Bd. of Cnty. Comm'rs, 2012 WY 163; Snake River Venture [v. Bd. of Cnty. Comm'rs, Teton Cnty.], 616 P.2d 744; Northfork [Citizens For Responsible Dev. v. Bd. of Cnty. Comm'rs of Park Cnty., 2010 WY 41]: Cited for the breadth of § 18-5-201 and the principle that county zoning must remain consistent with statutory limits and state policy.
• Bd. of Cnty. Comm'rs of Teton Cnty. v. Crow, 2003 WY 40: Used to confirm a broad conception of “general welfare” in zoning and to analogize that aquifer protection plainly promotes health/safety/welfare.
• River Springs Liab. Co. v. Bd. of Cnty. Comm'rs of Cnty. of Teton, 899 P.2d 1329: The key “no conflict” principle: counties may regulate so long as county regulation does not conflict with state regulation.
• Teton Cnty. Bd. of Cnty. Comm'rs v. Bd. of Land Comm'rs, 2025 WY 48: Reinforces that broad zoning grants remain bounded by state law and policy.

C. Equal protection / uniform operation

• Mills v. Reynolds, 837 P.2d 48; Reiter v. State, 2001 WY 116: The baseline articulation: classifications must bear a rational relationship to a legitimate state concern; equal protection does not require treating different things as the same.
• State v. Johnson, 2026 WY 1; Greenwalt [v. Ram Rest. Corp. of Wyo., 2003 WY 77]; Martin v. Bd. of Cnty. Comm'rs of Laramie Cnty., 2022 WY 21: Provide the rational-basis test mechanics: presumption of validity, heavy burden, courts do not second-guess policy line-drawing.
• Powder River Basin Res. Council v. Wyo. Dep't of Env't Quality, 2020 WY 127; Matter of Birkholz, 2019 WY 19; In re SNK, 2005 WY 30; Operation Save Am. v. City of Jackson, 2012 WY 51: Support the Court’s mootness holding on the first equal protection argument and its refusal to decide issues lacking continuing controversy.

D. Arbitrary/capricious review: Wyoming and federal anchors

• Dale v. S & S Builders, LLC, 2008 WY 84: Supplies Wyoming’s modern structure distinguishing substantial-evidence review for evidentiary findings from arbitrary/capricious as a “safety net.”
• Newman v. State ex rel. Wyo. Workers' Safety & Comp. Div., 2002 WY 91: Quoted via Dale for the “safety net” concept.
• Motor Vehicle Mfrs. Ass'n of the U.S., Inc. v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29; Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402; Bowman Transportation, Inc. v. Arkansas-Best Freight System, Inc., 419 U.S. 281; Burlington Truck Lines v. United States, 371 U.S. 156: Used to justify applying arbitrary/capricious review to informal rulemaking/legislative-type administrative action and to describe what “reasoned decisionmaking” entails (relevant data, explanation, rational connection).
• Gilbert [v. Bd. of Cnty. Comm'rs of Park Cnty., 2010 WY 68]; Monaghan Farms, Inc. v. Bd. of Cnty. Comm'rs of Albany Cnty., 2023 WY 31: Emphasize deference: disagreement in the record does not make the Board’s choice arbitrary; if exercised honestly and upon due consideration, it stands.
• Elec. Power Supply Ass'n v. FERC, 753 F.3d 216 (as quoted in a treatise excerpt): Reinforces that agencies must engage significant arguments raised before them—folded into the Court’s articulation of arbitrary/capricious review.

3.2. Legal Reasoning

A. County authority to zone for aquifer protection (and the “no conflict” boundary)

The Court’s authority analysis begins with the premise that counties are political subdivisions with only delegated powers, and that doubts about power are resolved against the county. It nonetheless finds the authority here because Wyo. Stat. Ann. § 18-5-201(a) is a “broad grant” authorizing zoning to promote public health, safety, morals, and general welfare. Protecting a drinking-water aquifer falls comfortably within those ends.

The key limiting principle, drawn from Seherr-Thoss v. Teton Cnty. Bd. of Cnty. Comm'rs, 2014 WY 82 and River Springs Liab. Co. v. Bd. of Cnty. Comm'rs of Cnty. of Teton, 899 P.2d 1329, is that local zoning cannot override state law or conflict with state regulation. The appellants framed the Environmental Quality Act and WDEQ authority as exclusive. The Court rejected exclusivity on this record, stressing that the Act and WDEQ rules anticipate cooperation and even delegation, and that nothing identified by appellants preempted land-use tools like minimum lot size inside an overlay zone.

A notable move is the Court’s characterization of subdivision-sewage review statutes and WDEQ rules (e.g., Wyo. Stat. Ann. § 18-5-306 and WDEQ Rules Ch. 23) as establishing minimum system standards and review procedures, not as occupying the field of land-use density restrictions. Thus, the 35-acre minimum lot size is treated as zoning density control rather than as an impermissible substitute for discharge permitting or water-quality standard-setting.

B. Equal protection: overlay procedures vs. district-amendment procedures

The Court addressed two equal protection theories. One was declared moot because subsequent amendments removed the challenged “previously surveyed parcels” limitation and “clear and convincing” burden language, leaving no live controversy.

On the remaining theory, the Court applied rational-basis review (economic/social welfare regulation) and held that using different procedures for APOZ boundary amendments than for underlying zoning district amendments is rationally related to aquifer protection. The conceptual distinction matters: district amendments change the underlying classification (agricultural/residential/commercial), while overlay boundaries impose additional protective standards across underlying districts. Tailoring process to that specialized protective function did not create an unconstitutional classification.

C. The opinion’s core administrative-law holding: arbitrary/capricious applies to agency legislative action

The Court explicitly resolves a previously open Wyoming question: whether WAPA’s arbitrary/capricious standard applies to agency “legislative” action (here, a county’s zoning amendments). The district court, reading Bienz I narrowly, had declined to apply arbitrary/capricious review because it was not listed explicitly in the Bienz I remand framework.

The Supreme Court corrected that approach: Wyo. Stat. Ann. § 16-3-114(c) does not distinguish between legislative and adjudicatory action, and the arbitrary and capricious standard is the default for agency actions not developed through trial-type evidentiary findings (with substantial evidence reserved for “true evidentiary questions,” and arbitrary/capricious also operating as a safety net).

D. Applying arbitrary/capricious to the 35-acre minimum lot size

The challengers attacked the evidentiary basis for aquifer risk, arguing the Board relied on flawed Wenck studies and ignored contrary nitrate-trend data. The Court framed the question as whether there was a rational basis in the whole record for the Board’s choice, not whether the Court would weigh the scientific dispute differently.

The Court found rational support in, among other items, the CAPP’s express discussion of “large lot zoning” (with 35-acre lots as an example), historical sampling suggesting septic density correlates with nitrate elevation, and modeling predicting higher nitrate levels at smaller lot sizes. Under the deferential standard, the existence of competing interpretations did not render the Board’s action arbitrary.

The Court also rejected statutory and practical objections:

• “De facto rezoning” claim: Even if the 35-acre minimum matched the agricultural district’s lot size, land use remained governed by underlying districts unless further restricted by the overlay; equivalence in one dimensional standard did not transform all underlying zoning into “agricultural.”
• Conflict with subdivision exemptions: The Court relied on county provisions preserving exemptions under Wyo. Stat. Ann. § 18-5-303(a)(i), concluding the overlay’s minimum lot size did not prevent uses authorized for exempt land divisions and thus did not violate § 18-5-201.
• Future expectations/nonconformities: Citing Sheridan Cnty. Comm'n v. V.O. Gold Props., LLC, 2011 WY 16, the Court held there is no vested right in prospective land uses; disappointment of development expectations and creation of nonconforming uses are common, lawful consequences of zoning changes.

3.3. Impact

• Administrative law (major doctrinal impact): The opinion squarely establishes that WAPA arbitrary-and-capricious review applies to agency legislative action (including local-government zoning amendments reviewed under WAPA). This fills the gap identified by the Court (“not yet considered in a published opinion”) and reduces the risk that agencies could avoid meaningful review by labeling action “legislative.”
• Practical effect on rulemaking records: Even in “informal” legislative settings, agencies should expect courts to examine whether the record shows a rational connection between the materials considered and the policy choice. While Wyoming does not require federal-style rulemaking procedures, the decision incentivizes building a defensible administrative record (reports, comments, responses, stated rationale).
• Local environmental zoning: The Court validates the use of zoning density controls (like minimum lot size) as an aquifer-protection tool where it does not conflict with state environmental regulation—an important signal to counties considering overlay zones to protect drinking water or sensitive resources.
• Equal protection challenges to process design: Tailored procedures for specialized overlays (vs. baseline district amendments) will generally survive rational-basis review when linked to legitimate public purposes and applied uniformly within the relevant class.
• Future litigation pressure points: The dissent provides a roadmap for future challengers: framing an overlay as de facto water-quality regulation may gain traction if a county’s ordinance more directly duplicates, contradicts, or conditions activities governed by WDEQ permits/standards, or if record evidence shows an attempt to supplant WDEQ’s judgment.

4. Complex Concepts Simplified

• Overlay zone: A layer of extra rules imposed on top of existing zoning districts. It does not necessarily change whether land is “agricultural” or “residential,” but it can add constraints (e.g., density, setbacks, prohibited uses) to protect a special resource.
• Legislative vs. adjudicatory agency action: “Legislative” action makes general, future-looking rules (like zoning amendments). “Adjudicatory” action decides a specific dispute for specific parties (like granting/denying a permit after a hearing).
• Arbitrary and capricious review: A deferential standard asking whether the agency had a rational basis and considered relevant factors. Courts do not re-decide policy; they check for reasoned decisionmaking and legality.
• Substantial evidence review: Used for fact-finding after trial-type hearings; asks whether the record contains enough evidence a reasonable mind could accept to support the agency’s findings.
• Rational-basis equal protection: Most economic/social regulations are upheld if the classification is rationally related to a legitimate government purpose. The challenger bears a heavy burden.
• Mootness: Courts generally do not decide issues when later events remove the dispute (here, later amendments eliminated the challenged boundary-language).
• Preemption/conflict in state-local regulation: Even broad zoning power cannot override state law. But local regulation may coexist with state regulation if it does not conflict—an idea the Court drew from River Springs Liab. Co. v. Bd. of Cnty. Comm'rs of Cnty. of Teton, 899 P.2d 1329.

5. Conclusion

2026 WY 76 delivers a consequential administrative-law holding for Wyoming: agency legislative action is subject to WAPA’s arbitrary-and-capricious review. Applying that framework, the Court upheld Albany County’s aquifer-protection overlay amendments, including a 35-acre minimum lot size, as within county zoning authority, consistent with state environmental law, and supported by a rational basis in the record. The concurrence emphasizes that the statute’s plain text alone compels the standard-of-review conclusion, while the dissent warns against allowing zoning to become a vehicle for de facto water-quality regulation in an area the Legislature has assigned comprehensively to WDEQ. In the near term, the decision strengthens judicial review of rulemaking-like agency actions while affirming counties’ ability to deploy land-use tools to protect critical drinking-water resources when done without conflict with state law.