Can I build an ADU in Riverton?

Most likely yes. Utah state law (HB 82) requires cities to allow internal ADUs. Riverton may also allow detached ADUs depending on zoning. Contact Riverton planning department to confirm your property qualifies.

How much does an ADU permit cost in Riverton?

ADU permit fees in Riverton follow the city fee schedule: Building Permit — Valuation-based per UBC fee table; Plan Check (Residential) — 45% of building permit fee; State Surcharge — 1% of permit fee. Under Utah law, impact fees for internal or attached ADUs may be reduced or waived — confirm with the building department.

Accessory Dwelling Unit (ADU) in Riverton, Utah

Required for construction of a secondary dwelling unit on a residential property in Riverton, including basement apartments, detached cottages, and garage conversions.

Verified 2026-06-27 · Source

When you need this permit

Property zoned for ADU use (check {city} zoning map)
Owner-occupancy of primary or accessory unit (varies by city)
Maximum size limits (typically 50-65% of primary dwelling or 1,000 sq ft)
Adequate parking (typically one additional off-street space)
Separate entrance from primary dwelling

Required documents

Req
Building Plans
Full construction drawings including floor plan, elevations, and sections
Req
Site Plan
Property layout showing both units, setbacks, parking, and access
Req
Zoning Compliance Letter
Verification that the property qualifies for an ADU under {city} zoning code
Req
Fire Separation Details
1-hour fire separation between units if attached/internal

Fee schedule

Fee type	Amount	Notes
Building Permit	Valuation-based per UBC fee table	—
Plan Check (Residential)	45% of building permit fee	—
State Surcharge	1% of permit fee	—

Review timeline

~14–30 business days

Typical estimate — confirm current times with the Riverton building department

Inspection process

1
Foundation
Footings, forms, rebar — before concrete pour
2
Framing
Structure, fire separation, egress windows
3
MEP Rough-In
Mechanical, electrical, plumbing rough-ins before walls closed
4
Insulation
Insulation and vapor barrier before drywall
5
Final
All work complete, smoke/CO detectors, address posted, ready for occupancy

Tips

Utah HB 82 (2021) requires most cities to allow at least internal ADUs — but Riverton may have additional local rules.
Basement apartments in Riverton must have egress windows in every bedroom (5.7 sq ft minimum opening).
ADU impact fees in Utah are often reduced or waived — ask Riverton about current fee schedules.
A rental business license from Riverton is typically required before renting an ADU.

Frequently asked questions

Can I build an ADU in Riverton?: Most likely yes. Utah state law (HB 82) requires cities to allow internal ADUs. Riverton may also allow detached ADUs depending on zoning. Contact Riverton planning department to confirm your property qualifies.
How much does an ADU permit cost in Riverton?: ADU permit fees in Riverton follow the city fee schedule: Building Permit — Valuation-based per UBC fee table; Plan Check (Residential) — 45% of building permit fee; State Surcharge — 1% of permit fee. Under Utah law, impact fees for internal or attached ADUs may be reduced or waived — confirm with the building department.

Sources & verification

Key facts verified against official sources. Last reviewed 2026-06-27.

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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