Accessory Dwelling Unit (ADU) Permit in Riverton, Wyoming
VerifiedThe City of Riverton has NO dedicated Accessory Dwelling Unit ordinance, definition, or permit category in its Zoning Code (Title 17, ecode360, chapters 17.04 through 17.88 reviewed in full). 'Accessory building/use' in Riverton's code means a subordinate NON-DWELLING structure (shed, garage, storage building) — not a secondary living unit. The closest legal pathway to a second housing unit on one lot is the R-2 Residential District, which permits 'multiple-family dwellings containing not more than two living units' (RMC § 17.32.010.A) as a true duplex — each unit independently meeting the district's own minimum floor area (425 sq ft per unit) — built and permitted as standard new residential construction, not as an accessory/ADU pathway.
Verified 2026-07-01 · Source
When you need this permit
- No ADU-specific zoning category exists; R-1, R-2A, and R-4 districts have no provision for a secondary dwelling unit on a single-family lot
- R-2 Residential District (RMC § 17.32.010–.040) permits a duplex (two full living units) as a permitted use: minimum lot area 5,000 sq ft, maximum 2 living units per lot, each unit minimum 425 sq ft floor area, max 40% lot coverage by main + accessory buildings, paved parking/driveway required for multi-family
- A true second unit in Riverton must be built under the standard residential building permit process for the applicable zoning district (R-2 for a duplex) — there is no owner-occupancy requirement, no size-ratio-to-primary-structure limit, and no distinct 'ADU' fee
- Property must first be confirmed as zoned R-2 (or petitioned for rezone) — R-1 does not allow a second dwelling unit
Required documents
- Req
Application for Building Permit
Same combined application used for any new residential construction; no ADU-specific form exists
- Req
Zoning Verification
Confirm R-2 zoning designation with the Community Development Department's Planning & Zoning division before applying
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| New Residential Construction (duplex, per RMC R-2 district) — same as residential-building-permit | $0.42 per square foot of building area (includes building and all building systems) | City of Riverton Resolution No. 1355, Category 2.A — no separate ADU fee line exists because no ADU category exists |
Review timeline
~1–30 business days
Typical estimate — confirm current times with the Riverton building department
Inspection process
- 1
Standard new-construction inspection sequence
Same sequence as residential-building-permit: temporary electric, footing, foundation wall, perimeter drain, underground plumbing, rough MEP, rough framing, sewer/water, final
Tips
- Riverton has NO accessory dwelling unit ordinance — do not confuse Riverton's 'accessory building/use' (RMC Chapter 17.20, which covers sheds/garages/non-dwelling subordinate structures) with an ADU. This was confirmed by reading the FULL Title 17 Zoning Code (ecode360, chapters 17.04–17.88) — the terms 'accessory dwelling,' 'ADU,' 'second dwelling,' 'guest house,' 'in-law,' and 'carriage house' do not appear anywhere in the code.
- The only legal path to a second housing unit on one lot is rezoning to (or already being in) R-2, which allows a duplex (max 2 units, 425 sq ft minimum floor area per unit) as a permitted use — this is a full second dwelling unit, not a reduced-standard 'accessory' unit, and carries no owner-occupancy requirement.
- Confirm your parcel's zoning district with Community Development/Planning & Zoning at (307) 856-2999 before designing any second unit — R-1 does not allow it at all.
Frequently asked questions
- Can I build an accessory dwelling unit (ADU) in Riverton, Wyoming?
- Riverton's Zoning Code (Title 17) has no ADU ordinance or permit category. The only way to add a second dwelling unit on one lot is if the property is zoned R-2, which permits a duplex (maximum two living units, each at least 425 sq ft) as a standard permitted use — built and permitted like any other new residential construction, not as a distinct 'ADU.' R-1-zoned single-family lots do not allow a second unit at all.
- Is there a different, cheaper permit process for a small second unit in Riverton?
- No. Because there is no ADU category, a second unit is charged the standard new-residential-construction fee ($0.42 per square foot of building area under Resolution No. 1355), the same as any other new dwelling.
Sources & verification
Verified against official sources. Last reviewed 2026-07-01.
- City of Riverton Community Development Department — Building Division — official building department
- Riverton Municipal Code Title 17 — Zoning, Chapter 17.20 (Accessory Uses) and Chapter 17.32 (R-2 Residential District) (ecode360, full title reviewed via print view)
- City of Riverton Resolution No. 1355 — Building Permit Fees and Planning Fees
Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Riverton building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.
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