Accessory Dwelling Unit (ADU) Permit in Evanston, Wyoming

Evanston requires an accessory dwelling unit (adu) permit for: ADUs are permitted (P8) or conditional-review (C8) uses only in specific residential districts per the Evanston City Code § 24-15 Schedule of Permitted Land Uses — confirm your lot's zoning district with the Engineering & Planning Department before applying; Only ONE accessory dwelling unit is permitted on a lot with a detached single-family dwelling; ADUs are prohibited on lots with attached single-family or multi-family dwellings; Lot must comply with the minimum lot area requirement for its zoning district, or the minimum usable open space per dwelling unit must be maintained with the ADU added; ADU cannot be subdivided or segregated in ownership from the principal dwelling, nor reclassified from accessory to principal use; Size limit: detached ADU may not exceed 50% of the principal dwelling's footprint or 1,200 sq ft, whichever is less (garage/porch/deck excluded from the calculation); minimum size 190 sq ft; a detached ADU of 400 sq ft or less (and at least 190 sq ft) must comply with IRC Appendix BB Tiny Houses; all accessory buildings combined (including a detached ADU) may not exceed 75% of the principal building's footprint; the size limitation does not apply to an ADU located entirely within a basement; Maximum 2 bedrooms/sleeping areas in the ADU; Building appearance must match or complement the principal dwelling's architectural style (siding, roofing, window materials); Detached ADUs comply with accessory-use setbacks/height limits; attached ADUs comply with principal-use setbacks for the district; One additional off-street parking space required for the ADU (paved, dust-free surface), beyond the district's normal minimum; ADU may not be a manufactured home, mobile home, travel unit, or temporary/seasonal structure (yurts, tents, units on skids) EXCEPT a manufactured home may serve as the ADU only in the LR-M or RR zoning districts and only if the principal building is also a manufactured home (must additionally meet Evanston City Code § 7-52.1); ADU may share water/sewer service with the principal unit if separate shutoff valves exist; no more than one bill per meter; ADU must have a separate house number from the principal dwelling; ADU must be on a permanent foundation (manufactured ADUs must meet § 7-52.1 foundation/skirt-wall requirements); Occupancy limited to no more than one family (persons related by blood, marriage, or adoption), with an exception allowing a non-family caretaker on a temporary/intermittent basis; One-year residency: the property owner must have physically lived in the principal dwelling as their primary residence for one year before applying for the ADU permit, EXCEPT an ADU may be built simultaneously with a new single-family home on a vacant/undeveloped lot without the waiting period; Owner-occupancy: the property owner must physically live in either the principal dwelling or the ADU as their primary residence for more than 50% of the calendar year for the ADU to be occupied; After City approval, the owner must record a 'Notice of Accessory Dwelling Unit Regulations' with the Uinta County Clerk (in a form approved by the Engineering and Planning Department); IRC Appendix BC (Accessory Dwelling Units) applies unless this Section specifies otherwise. If your project isn't listed, confirm with City of Evanston Engineering & Planning Department — Building Department at (307) 783-6470 before starting work.

In Evanston, the published City Building Permit Fee is: $0.010 × project cost (minimum charge $30.00). 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 Evanston typically runs 1–10 business days. This is an estimate, not a published figure — confirm current review times with City of Evanston Engineering & Planning Department — Building Department at (307) 783-6470.

You'll need: Ordinance No. 26-01 (ADU zoning amendment, adopted March 3, 2026); Zoning Requirements; Notice of Accessory Dwelling Unit Regulations (recorded with Uinta County Clerk). See the required-documents checklist on this page for details on each.

Apply through City of Evanston Engineering & Planning Department — Building Department at 33 Allegiance Circle, Evanston, WY 82930. Phone: (307) 783-6470, email: jhergert@evanstonwy.org. Office hours: Monday through Thursday 7:30 am–5 pm; Friday 7:30 am–1:30 pm (City Hall hours; contact Building Department directly for its own hours). Official information: https://engineering-planning-evanstonwy.hub.arcgis.com/pages/5d3f1221a8a94c8d9d12e0c6e6d8bea9.

Yes, as of Ordinance No. 26-01, adopted March 3, 2026. ADUs are permitted or conditional uses (depending on zoning district) on lots with a detached single-family dwelling, subject to 17 standards codified at Evanston City Code § 24-26.1 covering size, parking, occupancy, owner-occupancy, and more.

Yes. The property owner must have lived in the principal dwelling for one year before applying (with an exception for new construction on vacant lots), and the owner must continue to live in either the principal dwelling or the ADU as their primary residence for more than 50% of the calendar year.

The ordinance's stated purpose (per the Evanston Comprehensive Plan) includes using ADUs to generate rental income, but occupancy is limited to no more than one family at a time (or a caretaker for a family member), and the owner-occupancy requirement (§ 24-26.1(15)) must be maintained.