Gallatin County Commission adopts zoning edits to comply with state ADU law after residents urge caution

The Gallatin County Commission on Feb. 10 adopted zone text amendments intended to bring several rural zoning districts into compliance with 2025 state law that expands where accessory dwelling units (ADUs) are allowed.

Ashley Burke, county planning, told commissioners the amendments implement Senate Bill 532, now effective Oct. 1, 2025, and clarify that ADUs may be internal, attached or detached from a principal dwelling, do not count as using a development right, and must be subordinate to the primary residence. Burke also said the changes remove an examples list that had unintentionally excluded some types of ADUs and revise appeals language so the commission must decide appeals within 60 days.

The revisions are part of a package covering Rees Creek, Bridal Cottonwood and South Cottonwood Canyon zoning regulations. Planning staff presented the changes as county-initiated edits to ensure consistency with state law; the planning board recommended approval. Commissioner (mover) framed the edits as legally necessary, saying the county must align its regulations with state statute to avoid unenforceable rules.

Members of the public raised strong objections during the Rees Creek hearing. Melissa Blessing, a long-time Rees Creek resident, said the changes would accelerate development and harm wildlife and rural character, urging commissioners to reconsider striking conditional-use requirements: “Consistent zoning is death by overpopulation,” she said. Bill Jordan, a Belgrade resident, said he shared many of Blessing’s concerns but acknowledged the county is under a legal mandate to comply with SB 532 and asked planning staff to explain the county’s options.

Commissioners acknowledged the tension between local land-use preferences and state law. One commissioner said existing density caps on parcels will not change under the amendments, but allowed occupants of ADUs may now be unrelated renters, which could alter vehicle miles traveled and neighborhood activity. Commissioners adopted findings that the amendments comply with county growth policy and state law and voted to authorize the chair to sign the resolutions. Motions passed 2-0.

The commission also discussed technical clarifications in the Bridal Cottonwood and South Cottonwood drafts (size limits and proximity standards), and flagged one section in the natural-resources zone that staff suggested could be struck to avoid confusion; the commission agreed to continue consideration of that particular edit to the March 10 meeting so the public can be notified.

What happens next: The chair is authorized to sign the three zone text amendment resolutions; appeals of Board of Adjustment decisions can still be taken to district court, and the commission emphasized that the amendments are being made to comply with state law rather than to expand density beyond current development-right limits.