Accessory Dwelling Unit (ADU) Permit in Kalispell, Montana
VerifiedRequired for construction of a new accessory dwelling unit (or second unit as part of a duplex) on a residential property in Kalispell. Governed by Kalispell Municipal Code Section 27.20.082, substantially liberalized by Ordinance 1950 (effective May 4, 2026): an ADU is now a permitted use in any zone where a single-family dwelling is a permitted use.
Verified 2026-07-02 · Source
When you need this permit
- An ADU (or a second unit provided as part of a duplex) is a permitted use in any zone where a single-family dwelling is a permitted use (KMC 27.20.082(1), as amended by Ord. 1950, eff. 5-4-2026)
- Maximum height: single story, no more than 18 feet, unless the setbacks for a principal structure are met (in which case the district's standard maximum building height applies) — KMC 27.20.082(2)(a)
- Gross floor area of living space limited to no more than 1,000 square feet — KMC 27.20.082(2)(b)
- Rental periods of less than 30 days are not permitted for an ADU (i.e., ADUs cannot be used as short-term rentals) — KMC 27.20.082(2)(c)
- An ADU shall not contain more than one dwelling unit — KMC 27.20.082(2)(d)
- An ADU must meet the setbacks required for a principal structure, unless an existing conforming or nonconforming accessory structure is being converted into the ADU (in which case existing setbacks may be maintained) — KMC 27.20.082(3)(a)
- A building permit is required for all ADU construction, reviewed against the 2021 IRC and applicable zoning standards
- Separate trade permits (electrical, plumbing, mechanical) required for ADU construction
Required documents
- Required
Residential Building Permit Application
Standard building permit application; describe the ADU scope
- Required
Site Plan
Showing the ADU location, setbacks from lot lines, and relationship to the principal structure, to confirm compliance with KMC 27.20.082
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Building Permit Fee — valuation-based (same Building Permit Fee Schedule as new construction) | $23.50 minimum (valuation $1-$500) scaling to $6,444.85 for the first $1,000,000 plus $5.25 per additional $1,000 over $1,000,000 | City of Kalispell Building Permit Fee Schedule, effective 09/04/2024 — Kalispell does not publish a distinct ADU-specific fee variance |
Review timeline
14–21 business days
Kalispell’s published plan-review target
Inspection process
- 1
Foundation
Footings and foundation before concrete pour
- 2
Framing
Structural framing before wall cover
- 3
MEP Rough-In
Mechanical, electrical, plumbing rough-ins before walls closed — separate trade permits required
- 4
Final
All work complete, ready for occupancy
Tips
- Kalispell significantly expanded ADU eligibility effective May 4, 2026 (Ordinance 1950) — an ADU is now allowed in any zone where a single-family home is a permitted use, not just the previously-limited set of higher-density zones.
- ADUs are capped at 1,000 square feet of gross living area and a single story (18 feet max height) unless full principal-structure setbacks are met.
- ADUs cannot be rented for periods of less than 30 days — short-term rental use is prohibited by ordinance.
- Converting an existing conforming or nonconforming accessory structure (e.g., a detached garage) into an ADU allows the existing setbacks to be maintained rather than requiring full principal-structure setbacks.
Frequently asked questions
- Can I build an ADU on my property in Kalispell?
- As of Ordinance 1950 (effective May 4, 2026), an ADU is a permitted use in any zone where a single-family dwelling is a permitted use in Kalispell. It is limited to 1,000 square feet of living space, a single story/18-foot height (unless full principal-structure setbacks are met), and cannot be used as a short-term rental (minimum 30-day rental period). Source: Kalispell Municipal Code Section 27.20.082.
Sources & verification
Verified against official sources. Last reviewed 2026-07-02.
- City of Kalispell Building Department — official building department
- Kalispell Municipal Code Chapter 27.20 Supplementary Regulations — Section 27.20.082 Accessory Dwelling Units (eCode360)
- Current Res. Permit Fee Schedule (PDF, effective 09/04/2024)
- Building | City of Kalispell
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 Kalispell building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.
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