You are viewing the permanent link for the record currently in effect, published 2026-07-03.
Darby building permits
VerifiedDarby, Montana — as published 2026-07-03.
Verified 2026-07-03 · Source
Codes adopted
Permit types & fees
Building Permit (New Construction, Addition, Alteration, Repair)
VerifiedRequired for new construction, additions, alterations, repairs, mobile home placement, re-roofing, demolition, and other structural work in the Town of Darby. Reviewed against the IBC, IRC, IEBC, ISPSC, IECC, NEC, IMC, IFGC, and UPC as adopted statewide and enforced locally by Darby as a Montana DLI-certified jurisdiction (certified for Building, Plumbing, Mechanical, Electrical, and Swimming Pool). Applications are submitted in person at Town Hall.
Verified 2026-07-03 · Source
Requirements
- Building permit required for new construction, additions, alterations, repairs, mobile home installation, re-roofing, demolition, siding, signs, fences at/over 6 feet, and changes of use
- Complete and sign the Building Permit Application; fees are based on the Town's valuation-based fee table or the flat Miscellaneous Permit Fee schedule (whichever applies to the scope of work)
- Provide a plot plan showing building location and distances from each side of the lot, indicating alleys or streets
- Provide 2 sets of plans drawn to scale, including foundation, floor and roof framing, floor plans, and exterior elevations (one set may be submitted digitally)
- All work must conform to the most current adopted building codes (IBC, IRC, IEBC, ISPSC, IECC, NEC, IMC, IFGC, UPC) and Montana Administrative Rules (A.R.M.), plus applicable local codes
- Design criteria compliance: 46.0 psf ground snow load, 112 mph wind speed, Seismic Design Category C, severe weathering, 36-inch frost line depth, required ice shield underlayment
- Setback compliance: occupied buildings 25 ft front/rear, 5 ft sides (15 ft corner lot); accessory buildings 25 ft front, 7.5 ft rear, same side setbacks as occupied buildings
Required documents
- RequiredBuilding Permit ApplicationTown of Darby Building Permit Application (amended 2022-03-23), completed and submitted in person at Town Hall (101 E Tanner Ave / PO Box 37, Darby, MT 59829)
- RequiredPlot PlanSite plan showing building location and distances from each lot line, alleys, and streets
- RequiredConstruction Drawings (2 sets)Foundation, floor and roof framing, floor plans, and exterior elevations drawn to scale; one set may be digital
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Building Permit Fee — valuation $1.00 to $500.00 | $29.38 | Town of Darby Building Permit Fee Schedule (Res. 649, updated 4/13/2021) |
| Building Permit Fee — valuation $501.00 to $2,000.00 | $29.38 for the first $500.00, plus $3.81 for each additional $100.00 or fraction thereof | Town of Darby Building Permit Fee Schedule |
| Building Permit Fee — valuation $2,001.00 to $25,000.00 | $86.56 for the first $2,000.00, plus $17.50 for each additional $1,000.00 or fraction thereof | Town of Darby Building Permit Fee Schedule |
| Building Permit Fee — valuation $25,001.00 to $50,000.00 | $489.06 for the first $25,000.00, plus $12.63 for each additional $1,000.00 or fraction thereof | Town of Darby Building Permit Fee Schedule |
| Building Permit Fee — valuation $50,001.00 to $100,000.00 | $804.69 for the first $50,000.00, plus $8.75 for each additional $1,000.00 or fraction thereof | Town of Darby Building Permit Fee Schedule |
| Building Permit Fee — valuation $100,001.00 to $500,000.00 | $1,242.19 for the first $100,000.00, plus $7.00 for each additional $1,000.00 or fraction thereof | Town of Darby Building Permit Fee Schedule |
| Building Permit Fee — valuation $500,001.00 to $1,000,000.00 | $4,042.19 for the first $500,000.00, plus $6.19 for each additional $1,000.00 or fraction thereof | Town of Darby Building Permit Fee Schedule |
| Building Permit Fee — valuation $1,000,001.00 and up | $7,010.94 for the first $1,000,000.00, plus $4.56 for each additional $1,000.00 or fraction thereof | Town of Darby Building Permit Fee Schedule |
| Re-roof up to 3,000 square feet (flat fee) | $50.00 | Town of Darby Building Permit Fee Schedule, Miscellaneous Permit Fees table |
| Re-roof over 3,000 square feet (flat fee) | $75.00 | Town of Darby Building Permit Fee Schedule, Miscellaneous Permit Fees table |
| Fence (no fee if under 6 feet) | Flat Miscellaneous Permit Fee applies at/over 6 feet (specific dollar amount not legibly resolved from the source PDF's table alignment) | Town of Darby Building Permit Fee Schedule; confidence: this line's exact dollar figure could not be cleanly parsed from the source PDF table layout and is reported as unresolved rather than guessed |
| Siding (flat fee) | $50.00 | Town of Darby Building Permit Fee Schedule, Miscellaneous Permit Fees table |
| Demolition (flat fee) | $50.00 | Town of Darby Building Permit Fee Schedule, Miscellaneous Permit Fees table |
| Sign (flat fee) | $75.00 | Town of Darby Building Permit Fee Schedule, Miscellaneous Permit Fees table |
| Change of use (flat fee) | $30.00 | Town of Darby Building Permit Fee Schedule, Miscellaneous Permit Fees table |
| Footing or Foundation only | $1 per lineal foot, or $5 per pier, or based on valuation | Town of Darby Building Permit Fee Schedule, Miscellaneous Permit Fees table |
| Other Inspections and Fees (after-hours, re-inspection, unlisted inspection, additional plan review) | $47.00 per hour minimum (half-hour minimum for re-inspection/plan-review line items), or the total hourly cost to the jurisdiction, whichever is greater | Town of Darby Building Permit Fee Schedule |
Electrical Permit
VerifiedRequired for new construction, renovation, or repair of electrical systems within the Town of Darby. Darby is a Montana DLI-certified jurisdiction for electrical permitting and has applied for and inspected electrical permits directly (rather than routing to the state) effective September 16, 2021.
Verified 2026-07-03 · Source
Requirements
- Electrical permit required for new construction, renovation, or repair of electrical systems
- Complete all sections of the Electrical Permit Application; form may be submitted electronically via the form's submit button or in person at Town Hall
- For commercial projects: include load calculations, equipment specifications, grounding detail, and panel/feeder schedule(s)
- Contractor license number and master/journeyman license number required on the application
- Related permit numbers (Building, Plumbing, Mechanical) must be cross-referenced on the application if applicable
Required documents
- RequiredElectrical Permit ApplicationTown of Darby Electrical Permit Application (2021), submitted in person at Town Hall or electronically
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Electrical Permit Fee — valuation $1.00 to $1,000 | $45 for the first $500 plus 6.0% of the balance of construction value | Town of Darby Electrical Permit Application fee table |
| Electrical Permit Fee — valuation $1,001 to $10,000 | $75 for the first $1,000 plus 2.0% of the balance of construction value | Town of Darby Electrical Permit Application fee table |
| Electrical Permit Fee — valuation $10,001 to $50,000 | $255 for the first $10,000 plus 0.5% of the balance of construction value | Town of Darby Electrical Permit Application fee table |
| Electrical Permit Fee — valuation $50,001 or more | $455 for the first $50,000 plus 0.3% of the balance of construction value | Town of Darby Electrical Permit Application fee table |
Plumbing Permit
VerifiedRequired for new construction, remodel/alteration, or addition involving plumbing systems within the Town of Darby, governed by the Uniform Plumbing Code (UPC) and Montana statute (Title 50, Chapter 60, Section 505, MCA; ARM 8.70.302-8.70.305). Darby is a Montana DLI-certified jurisdiction for plumbing permitting and applies for/inspects plumbing permits directly, effective September 16, 2021.
Verified 2026-07-03 · Source
Requirements
- Plumbing work must be performed by a licensed Master Plumber, per Title 50, Chapter 60, Section 505, MCA and ARM 8.70.302-8.70.305
- Permit becomes null and void if authorized work has not commenced within 180 days, or if it exceeds the expiration date on the issued permit
- 24 hours' notice required for all inspections
- Applicant/property owner is responsible for compliance with all applicable Uniform Plumbing Code and International Building Code provisions
Required documents
- RequiredPlumbing Permit ApplicationTown of Darby Plumbing Permit Application (final, 2023-08-22), submitted at Town Hall (101 E Tanner Ave / PO Box 37, Darby, MT 59829)
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Plumbing Permit Fee — valuation $1.00 to $1,000 | $75 for the first $1,000 plus 2.0% of the balance of construction value | Town of Darby Plumbing Permit Application fee table (the same table also lists a $45-for-first-$500-plus-6.0%-of-balance tier consistent with the Electrical/Mechanical fee structure) |
| Plumbing Permit Fee — valuation $1,001 to $10,000 | $225 for the first $10,000 plus 0.5% of the balance of construction value | Town of Darby Plumbing Permit Application fee table |
| Plumbing Permit Fee — valuation $10,001 to $50,000 | $455 for the first $50,000 plus 0.3% of the balance of construction value | Town of Darby Plumbing Permit Application fee table |
Mechanical / HVAC Permit
VerifiedRequired for new construction, renovation, or repair of mechanical (HVAC) systems within the Town of Darby. Darby is a Montana DLI-certified jurisdiction for mechanical permitting and applies for/inspects mechanical permits directly, effective September 16, 2021.
Verified 2026-07-03 · Source
Requirements
- 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
Required documents
- RequiredMechanical Permit ApplicationTown of Darby Mechanical Permit Application (2021), submitted in person at Town Hall or electronically
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Mechanical Permit Fee — valuation $1.00 to $1,000 | $75 for the first $1,000 plus 2.0% of the balance of construction value | Town of Darby Mechanical Permit Application fee table (the same table also lists a $45-for-first-$500-plus-6.0%-of-balance tier) |
| Mechanical Permit Fee — valuation $1,001 to $10,000 | $255 for the first $10,000 plus 0.5% of the balance of construction value | Town of Darby Mechanical Permit Application fee table |
| Mechanical Permit Fee — valuation $10,001 to $50,000 | $455 for the first $50,000 plus 0.3% of the balance of construction value | Town of Darby Mechanical Permit Application fee table |
Solar PV Permit (via Town Electrical Permit)
VerifiedDarby is a Montana DLI-certified jurisdiction for Electrical permitting (effective September 16, 2021) and self-administers electrical permits directly rather than routing to the state. The Town's own Electrical Permit Application (2021) — the same form and valuation-based fee table used for all electrical work in Darby — does not contain a distinct solar/photovoltaic/alternative-energy line item or checkbox; a residential or commercial solar PV interconnection is therefore billed under the Town's general valuation-based Electrical Permit, with racking/structural attachment covered by the Town's Residential Building Permit (Darby also holds full B, P, M, E, SP certification).
Verified 2026-07-20 · Source
Requirements
- Complete the Town of Darby Electrical Permit Application for the interconnection/wiring work, submitted in person at Town Hall or electronically
- Complete the Town of Darby Residential Building Permit Application for the roof-mount racking/structural attachment portion of a rooftop installation
- Contractor license number and master/journeyman license number required on the electrical application
- Grid-tied systems require a licensed electrical contractor to perform the final utility interconnection, consistent with statewide Montana electrical-permitting practice
Required documents
- RequiredElectrical Permit ApplicationTown of Darby Electrical Permit Application (2021); no solar-specific field exists — filed as standard electrical work with a declared valuation
- OptionalResidential Building Permit ApplicationRequired for the structural/racking portion of a rooftop solar installation, since Darby holds full local Building certification
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Electrical Permit Fee — valuation $1.00 to $1,000 | $45 for the first $500 plus 6.0% of the balance of construction value | Town of Darby Electrical Permit Application fee table — the same schedule applied to all electrical work in Darby, including a solar PV interconnection's declared valuation; no solar-specific line item exists on the Town's own application form, confirmed by direct review of the PDF |
| Electrical Permit Fee — valuation $1,001 to $10,000 | $75 for the first $1,000 plus 2.0% of the balance of construction value | Town of Darby Electrical Permit Application fee table |
| Electrical Permit Fee — valuation $10,001 to $50,000 | $255 for the first $10,000 plus 0.5% of the balance of construction value | Town of Darby Electrical Permit Application fee table |
| Electrical Permit Fee — valuation $50,001 or more | $455 for the first $50,000 plus 0.3% of the balance of construction value | Town of Darby Electrical Permit Application fee table |
Electric Vehicle Charging Station Permit (via Town Electrical Permit)
VerifiedDarby is a Montana DLI-certified jurisdiction for Electrical permitting (effective September 16, 2021) and self-administers electrical permits directly rather than routing to the state -- the same mechanism documented in this file's electrical-permit and solar-pv-permit entries. The Town's own Electrical Permit Application (2021), the same form and valuation-based fee table used for all electrical work in Darby, does not contain a distinct EV charger/EVSE line item or checkbox; an EV charger installation is therefore billed under the Town's general valuation-based Electrical Permit, with no separate EV-specific permit or fee. Re-chased 2026-07-20: directly re-fetched and confirmed the Town's live Electrical Permit Application PDF still hosts this exact same fee table verbatim, so it remains the real, currently-effective governing figure for this permit.
Verified 2026-07-20 · Source
Requirements
- Complete the Town of Darby Electrical Permit Application for the charger circuit/installation work, submitted in person at Town Hall or electronically
- Contractor license number and master/journeyman license number required on the application
- No EV-charger-specific line item exists on the Town's own Electrical Permit Application form, confirmed by direct review of the PDF; the installation is declared and billed at its construction valuation like any other electrical work
- For a Level 3 or commercial-scale charger requiring a new structure (e.g., a canopy), a separate Town of Darby Residential/Commercial Building Permit would additionally apply for that structural portion, since Darby holds full local Building certification
Required documents
- RequiredElectrical Permit ApplicationTown of Darby Electrical Permit Application (2021); no EV-charger-specific field exists -- filed as standard electrical work with a declared valuation
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Electrical Permit Fee — valuation $1.00 to $1,000 | $45 for the first $500 plus 6.0% of the balance of construction value | Town of Darby Electrical Permit Application fee table -- the same schedule applied to all electrical work in Darby, including an EV charger's declared valuation; no EV-specific line item exists on the Town's own application form, confirmed by direct review of the PDF Re-confirmed live 2026-07-20 against the same currently-hosted PDF. |
| Electrical Permit Fee — valuation $1,001 to $10,000 | $75 for the first $1,000 plus 2.0% of the balance of construction value | Town of Darby Electrical Permit Application fee table Re-confirmed live 2026-07-20 against the same currently-hosted PDF. |
| Electrical Permit Fee — valuation $10,001 to $50,000 | $255 for the first $10,000 plus 0.5% of the balance of construction value | Town of Darby Electrical Permit Application fee table Re-confirmed live 2026-07-20 against the same currently-hosted PDF. |
| Electrical Permit Fee — valuation $50,001 or more | $455 for the first $50,000 plus 0.3% of the balance of construction value | Town of Darby Electrical Permit Application fee table Re-confirmed live 2026-07-20 against the same currently-hosted PDF. |
Sign Permit (via Town Building Permit)
VerifiedRequired for installing or replacing a sign within the Town of Darby. Darby publishes no separate sign-permit application form or standalone sign ordinance; a sign is filed as a flat-fee line item on the Town's general Building Permit process (the same application and in-person submission at Town Hall used for all other structural/building work), per the Town's own Building Permit Fee Schedule.
Verified 2026-07-22 · Source
Requirements
- File using the Town of Darby Building Permit Application (same form and process as other building work); no separate sign-specific application form is published by the Town
- Fee is a flat Miscellaneous Permit Fee per the Town's Building Permit Fee Schedule (see fees)
- No dedicated sign code, size/height/setback standard, or zoning ordinance section specific to signs was found published on the Town's website as of this review; whether the general Building Permit setback rules (25 ft front/rear, 5 ft sides for occupied structures) apply to freestanding signs is not confirmed either way
Required documents
- RequiredBuilding Permit ApplicationTown of Darby Building Permit Application (amended 2022-03-23); the same general-purpose form used for all building work is used for a sign, since no separate sign application exists
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Sign (flat fee) | $50.00 | Town of Darby Building Permit Fee Schedule (Res. 649, updated 4/13/2021), Miscellaneous Permit Fees table. Re-extracted and cross-checked directly from the source PDF on 2026-07-22 using two independent extraction methods (pdftotext -table and pdftotext -raw), both of which pair 'Sign' with $50.00 and 'Change of use' with $75.00 -- the opposite of the $75.00/$30.00 pairing recorded in this same file's residential-building-permit entry (lastVerified 2026-07-03), which appears to have resulted from a row-misaligned read of the same PDF's column layout via a third extraction method. This entry uses the freshly re-verified pairing; the residential-building-permit entry was left untouched per this task's scope (edit exactly one permitTypes addition batch, no existing entries modified) and should be corrected in a follow-up pass. |
Change of Use Permit (via Town Building Permit)
VerifiedRequired when a building's occupancy or use classification changes within the Town of Darby. Darby publishes no separate change-of-use application form or standalone certificate-of-occupancy process; a change of use is filed as a flat-fee line item on the Town's general Building Permit process (the same application and in-person submission at Town Hall used for all other structural/building work), per the Town's own Building Permit Fee Schedule.
Verified 2026-07-22 · Source
Requirements
- File using the Town of Darby Building Permit Application (same form and process as other building work); no separate change-of-use-specific application form is published by the Town
- Fee is a flat Miscellaneous Permit Fee per the Town's Building Permit Fee Schedule (see fees)
- No standalone certificate-of-occupancy (CO) permit or process, distinct from the change-of-use line item, was found published on the Town's website as of this review
Required documents
- RequiredBuilding Permit ApplicationTown of Darby Building Permit Application (amended 2022-03-23); the same general-purpose form used for all building work is used for a change of use, since no separate application exists
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Change of use (flat fee) | $75.00 | Town of Darby Building Permit Fee Schedule (Res. 649, updated 4/13/2021), Miscellaneous Permit Fees table. Re-extracted and cross-checked directly from the source PDF on 2026-07-22 using two independent extraction methods (pdftotext -table and pdftotext -raw), both of which pair 'Change of use' with $75.00 and 'Sign' with $50.00 -- the opposite of the $30.00/$75.00 pairing recorded in this same file's residential-building-permit entry (lastVerified 2026-07-03), which appears to have resulted from a row-misaligned read of the same PDF's column layout via a third extraction method. This entry uses the freshly re-verified pairing; the residential-building-permit entry was left untouched per this task's scope and should be corrected in a follow-up pass. |
Fire Sprinkler / Fire Alarm Permit
No dedicated local fire-sprinkler or fire-alarm permitting process is published by the Town of Darby. Darby's Montana DLI trade certification (verified via the DLI's Certified City, County and Town Programs roster, cited elsewhere in this file) covers Building (B), Plumbing (P), Mechanical (M), Electrical (E), and Swimming Pool (SP) only -- it does NOT include Fire Protection (FP), the trade category DLI uses for fire-suppression/sprinkler work. The Town's own Building Permit Fee Schedule contains no fire, sprinkler, or alarm line item. Fire service in Darby is provided by the Darby Volunteer Fire Department (contracted service, non-emergency (406) 821-3100, 500 N. Main Street), but no published plan-review or permit process for fire sprinkler/alarm systems was found on the Town's site, and the department's own website (darbyfire.com) returned an HTTP 404 error on direct fetch during this review.
Reviewed 2026-07-22 · Source
Requirements
- No Darby-specific fire-sprinkler or fire-alarm permit requirements are published; contact the Town of Darby Building Department ((406) 821-3753) and the Darby Volunteer Fire Department (non-emergency (406) 821-3100) directly to confirm the current review pathway for a specific project
- Montana licenses fire-protection contractors/installers statewide through the DLI Fire Protection License Program (business and individual endorsements for selling, installing, and servicing fire protection systems), separate from any local plan-review or permitting step -- this governs who may perform the work, not who reviews/permits it locally
- Darby is not DLI-certified for the Fire Protection (FP) trade (its certification covers B, P, M, E, SP only), so fire-suppression plan review does not fall under the Town's own certified Building Department program the way Electrical, Plumbing, and Mechanical work does
Required documents
Fee schedule
| Fee type | Amount | Notes |
|---|---|---|
| Fire sprinkler/alarm permit fee | Not published | No fire, sprinkler, or alarm line item appears anywhere in the Town of Darby's Building Permit Fee Schedule (confirmed by direct text search of the source PDF); no fee could be identified after exhausting the Town's published materials. |
Sources & verification
Verified against official sources. Last reviewed 2026-07-03.
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 Darby building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.