Accessory Dwelling Unit (ADU) Permit in Unincorporated Campbell County, Wyoming

Unincorporated Campbell County requires an accessory dwelling unit (adu) permit for: Applies only in R-L, R-R, R-S, R-1, and A-L Zoning Districts (Chapter 7 § 45.70(2)); One ADU permitted per lot in R-L/R-R/R-S/R-1; one ADU per Primary Dwelling Unit in A-L (multiple allowed in A-L only if each Primary Dwelling meets the 10-acre minimum land area under § 15.10(1)); Written verification required that the Homeowners' Association, Improvement & Service District, or recorded Covenants Agreement approves the specific ADU; if none of these entities exist for the subdivision, a Conditional Use Permit (§10.55, $200 fee) is required instead; Maximum Building Footprint Living Area: the SMALLER of 60% of the Primary Dwelling Unit's footprint, or 1,100 sq. ft.; Maximum height: cannot exceed the height of the Primary Dwelling Unit; Detached ADUs may not be located in the front or side yard areas of the Principal Dwelling (except existing buildings under §45.70(6)(e)); HUD Manufactured Homes, RVs, and boats are PROHIBITED as ADUs, except Park Model Homes are allowed in A-L/R-L/R-R districts where the Primary Dwelling is itself a manufactured home; Attached ADUs must comply with the Two-Family Dwelling provisions of the currently adopted IRC, including Appendix AK sound transmission requirements; Detached ADUs (new construction) must comply with the currently adopted IRC; attached garages to the ADU may not exceed the ADU's own allowable footprint; Existing detached accessory structures converted to an ADU are not limited by a shop/garage-to-ADU area ratio, but the ADU living area itself cannot exceed the § 45.70(6)(a) size cap; Septic/sewer: ADU's small wastewater system may interconnect with the Primary Dwelling's system (not prohibited) but must comply with Chapter 4 Building Regulations. If your project isn't listed, confirm with Campbell County Department of Public Works — Building, Planning & Zoning Division at (307) 682-1970 before starting work.

In Unincorporated Campbell County, the published ADU Zoning review (Review Process 1) is: No fee. Additional published fees: Conditional Use Permit (only if no HOA/I&S District/Covenants exists for the subdivision) — $200.00; Building Permit for ADU construction — No fee. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Plan review for an accessory dwelling unit (adu) permit in Unincorporated Campbell County typically runs 3–21 business days. This is an estimate, not a published figure — confirm current review times with Campbell County Department of Public Works — Building, Planning & Zoning Division at (307) 682-1970.

You'll need: Zoning Certificate Application (for the ADU land use); HOA / Improvement & Service District / Covenants Approval Letter; Building Permit & Zoning Certificate Application. See the required-documents checklist on this page for details on each.

Apply through Campbell County Department of Public Works — Building, Planning & Zoning Division at 500 S. Gillette Ave., Suite 1500, Gillette, WY 82716. Phone: (307) 682-1970, email: septic@campbellcountywy.gov (Small Wastewater System applications); planning@campbellcountywy.gov (Planning & Zoning); general Public Works (307) 685-8061. Office hours: Mon–Fri, 8:00 a.m.–5:00 p.m.. Official information: https://www.ccgov.net/286/Building-Division.

Yes. Chapter 7 Zoning Regulations Section 45.70 creates a dedicated ADU category for the R-L, R-R, R-S, R-1, and A-L Zoning Districts, approved administratively (Review Process 1) subject to HOA/Improvement & Service District/Covenants approval.

The maximum Building Footprint Living Area is the smaller of 60% of the Primary Dwelling Unit's footprint or 1,100 square feet, and the ADU's height cannot exceed the Primary Dwelling's height (Chapter 7 § 45.70(6)).

If there is no Homeowners' Association, Improvement & Service District, or recorded Covenants Agreement for the subdivision, the ADU application is processed instead as a Conditional Use Permit under Chapter 7 Section 10.55, which carries a $200 fee.