Mechanical / HVAC Permit in Darby, Montana

Darby requires a mechanical / hvac permit for: Mechanical permit required for new construction, renovation, or repair of mechanical systems; Complete all sections of the Mechanical Permit Application; form may be submitted electronically or in person at Town Hall; For new commercial projects: include load calculations and equipment specifications; Contractor license number required on the application. If your project isn't listed, confirm with Town of Darby Building Department at (406) 821-3753 before starting work.

In Darby, the published Mechanical Permit Fee — valuation $1.00 to $1,000 is: $75 for the first $1,000 plus 2.0% of the balance of construction value. Additional published fees: Mechanical Permit Fee — valuation $1,001 to $10,000 — $255 for the first $10,000 plus 0.5% of the balance of construction value; Mechanical Permit Fee — valuation $10,001 to $50,000 — $455 for the first $50,000 plus 0.3% of the balance of construction value. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Darby does not publish a plan-review timeline for this permit. Contact Town of Darby Building Department at (406) 821-3753 for current turnaround.

You'll need: Mechanical Permit Application. See the required-documents checklist on this page for details on each.

Apply through Town of Darby Building Department at 101 E Tanner Ave / PO Box 37, Darby, MT 59829. Phone: (406) 821-3753, email: darbymontana@usa.net. Office hours: Town Hall: Monday-Friday, 8:00 am - 5:00 pm. Source: Town of Darby Contact Us page (darbymt.net/a/contact-us/). Building permit applications and fee payment are handled in person at Town Hall; the current contracted building inspector is Construct Montana, LLC, (406) 552-3238, inspector@constructmt.com; the Montana DLI-certified program contact of record is Tim Netzley, (406) 961-2423 (also listed as (406) 880-5832 on the Town's own Building Permit Application form).. Official information: https://www.darbymt.net/a/building-related-code/.

Darby, Montana has adopted: Montana has a mandatory statewide building code administered by the Montana Department of Labor & Industry (DLI) Building Codes Bureau, amended by the Administrative Rules of Montana (ARM) Title 24, Chapter 301. Cities, counties, and towns may become 'certified' to locally administer permitting and inspection for all or part of the code; a certified local program's adopted code 'may include only codes adopted by the Building Codes Bureau' (ARM 24.301.202). Non-certified areas fall under direct state administration by the DLI Building Codes Bureau. Source: Montana DLI Building Codes Bureau, Certified City, County and Town Programs page (bsd.dli.mt.gov/building-codes-permits/certified-government).; Darby is a Montana DLI-certified jurisdiction for Building (B), Plumbing (P), Mechanical (M), Electrical (E), and Swimming Pool (SP) — full trade certification — within Darby town limits ('City Limits' jurisdiction scope). Certified program contact on file with DLI: Tim Netzley, (406) 961-2423. Verified directly against the DLI's official 'Certified City, County and Town Programs' roster PDF (updated 2026-04-22): row reads 'Darby | B, P, M, E, SP | Tim Netzley | 961-2423 | City Limits'. Source: https://bsd.dli.mt.gov/_docs/building-codes-permits/certified-city.pdf; The Town's own Building Permit Application states: 'All work shall conform to the most current building codes - IBC, IRC, IEBC, ISPSC, IECC, NEC, IMC, IFGC, UPC and Montana A.R.M; and applicable local codes' and 'Electrical, Plumbing, Mechanical permits are applied for and inspected by Town of Darby, effective September 16, 2021.' Source: Town of Darby Building Permit Application (amended 2022-03-23), https://www.darbymt.net/a/wp-content/uploads/2022/03/Building-Permit-Application-amended-2022-03-23.pdf; Montana uses the Uniform Plumbing Code (UPC), not the International Plumbing Code — confirmed on Darby's own Plumbing Permit Application, which requires a licensed Master Plumber 'in accordance with Title 50, Chapter 60, Section 505, MCA and Sections 8.70.302, 8.70.303, 8.70.304, and 8.70.305 ARM' and states 'All provisions of the Uniform Plumbing Codes and the International Building codes will be strictly enforced.' Source: Town of Darby Plumbing Permit Application (2023-08-22), https://www.darbymt.net/a/wp-content/uploads/2023/08/Plumbing-Permit-Final-TOD-2023-08-22.pdf; State-adopted code editions in effect statewide since June 11, 2022 (per DLI Building Codes Bureau, applicable as the baseline Darby enforces as a certified jurisdiction): 2021 IBC, 2021 IRC, 2021 IEBC, 2021 IMC, 2021 IFGC, 2021 IECC, 2021 UPC, 2020 NEC, 2021 ISPSC. Source: Montana DLI Building Codes Bureau, Current Codes page, https://bsd.dli.mt.gov/building-codes-permits/current-codes. Darby's own permit application does not list specific code-edition years locally; no local re-adoption ordinance/administrative order text was found published online (Town Hall does not publish a codified municipal code online) beyond the applications' own reference to 'most current building codes'.. Local amendments apply — see the Darby overview page for the full list.