Accessory Dwelling Unit (ADU) Permit in Green River, Wyoming

Green River requires an accessory dwelling unit (adu) permit for: No ADU-specific permit or zoning pathway exists in Green River; do not apply expecting an 'ADU' permit type; An accessory structure (garage, shed, workshop) may NOT include residential occupancy per Zoning Code Section 9.6.A ('Accessory Buildings, Structures and Uses') and the Shed & Accessory Structure Brochure; A genuine second dwelling unit on a property requires the lot to be zoned for Multi-Unit Dwelling use (the zoning Table of Uses permits 'Multi-Unit Dwelling' only in specific districts, e.g. R-3/R-4, not R-1/R-2 single-family districts) — this is processed as a standard residential building permit for a duplex/multi-family structure, not an ADU permit; Confirm zoning district and permitted use eligibility with Development Services/Planning before attempting any second-unit project. If your project isn't listed, confirm with City of Green River Development Services — Building Inspection Division at (307) 872-6140 before starting work.

Plan review for an accessory dwelling unit (adu) permit in Green River typically runs 1–14 business days. This is an estimate, not a published figure — confirm current review times with City of Green River Development Services — Building Inspection Division at (307) 872-6140.

Depending on your project, Green River may also ask for: Shed & Accessory Structure Brochure (DocumentCenter Doc #4092). See the required-documents checklist on this page for details on each.

Apply through City of Green River Development Services — Building Inspection Division at 50 E 2nd North Street, Green River, WY 82935. Phone: (307) 872-6140, email: Contact via Development Services (see department website). Office hours: Monday through Friday, 8:00 a.m. to 5:00 p.m.. Official information: https://www.grwyo.org/87/Building-Inspection.

Green River, Wyoming has adopted: 2024 International Building Code (IBC), including Appendices B, I, J — adopted by City of Green River Code of Ordinances Sec. 7-16 (Ord. No. 16-02, 8-1-16; amended through Ord. No. 25-01, 1-21-25); Chapter 27 (Electrical) of the IBC is deleted by local amendment since electrical is separately governed by the local NEC adoption (Sec. 7-76); 2024 International Residential Code (IRC), including Appendices AA, BA, BE, BF, CA, CB, CD — Sec. 7-17 (Ord. No. 25-01, 1-21-25); local design criteria: Ground Snow Load 30 psf, Wind Speed 115 mph, Seismic Design Category C, Weathering Severe, Frost Line Depth 42 inches, Termite None to Slight, Winter Design Temp -20°F, Ice Shield Underlayment Required, Air Freezing Index 2282, Elevation 6,132 ft; 2024 International Plumbing Code (IPC), including all appendices — Sec. 7-31 (Ord. No. 25-01, 1-21-25), with local amendment to Section 305.4 (Freezing) restricting exterior/attic/crawlspace pipe placement; 2024 International Mechanical Code (IMC), including all appendices — Sec. 7-46 (Ord. No. 25-01, 1-21-25); 2024 International Fuel Gas Code (IFGC) — Sec. 7-91 (Ord. No. 25-01, 1-21-25); National Electrical Code (NEC), latest edition as adopted by the Wyoming State Fire Marshal's Office (2023 NEC was in effect through June 30, 2026; per wsfm.wyo.gov/electrical-safety, the 2026 NEC took effect statewide July 1, 2026) — adopted by reference for Green River under Sec. 7-76 (Ord. No. 16-02, 8-1-16; amended through Ord. No. 25-01, 1-21-25); enforced locally by the City under Home Rule, not by the state electrical program. Local amendments apply — see the Green River overview page for the full list.

Green River's zoning code has no dedicated ADU permit or use category. Its definition of an accessory structure/use explicitly excludes residential occupancy. A genuine second dwelling unit requires the property to be zoned for Multi-Unit Dwelling use (e.g., R-3 or R-4), processed as a standard residential building permit for that use — not as an accessory structure to an existing single-family home.