The Complete Step-by-Step Guide to Getting a Building Permit in Montana
Not all counties are alike when getting a building
permit in Montana
Picture two neighbors on opposite sides of a county line, both pouring a patio and setting a hot tub the same weekend. One of them needs three permits and a septic evaluation. The other needs nothing but an electrician. Same project, same state, completely different paperwork. That's not a hypothetical, it's just how Montana's permit system actually works. There is no single Montana building code that applies uniformly from Eureka to Ekalaka. Instead, permitting authority is split between the state and whichever cities or counties have taken it over locally, and which one applies to you depends entirely on your address.
That fragmentation is exactly why "do I need a permit for this?" doesn't have a one-line answer, and why we've laid this guide out as an actual sequence of steps rather than a general overview. Follow it in order, from figuring out who regulates your property all the way through your final inspection, and you'll know exactly where you stand before a shovel ever touches the ground.
Why this is worth doing right the first time
A permit isn't just a fee and a form. It's the record that an inspector, not just your contractor, verified the gas line, the electrical circuit, or the structural framing was done to code. That record matters at resale, when a buyer's inspector or a title company asks whether work was permitted. It matters to your homeowner's insurance, which can deny a claim tied to unpermitted work. And for anything involving gas or 240V electrical, which describes most of what goes into an outdoor kitchen, hot tub, or pool, it's the difference between a system that's been checked by a third party and one that hasn't. None of that shows up until something goes wrong, which is exactly when you don't want to be finding out.
Step 1: Determine who actually regulates your property
Before you research a single code requirement, find out which of three possible authorities governs your land, because the answer changes everything downstream:
A certified city.
Some Montana cities have been certified by the state to write and enforce their own building codes across the full set of trades: building, plumbing, electrical, mechanical, and sometimes site prep. Missoula and Bozeman both fall into this category.
A certified county.
A handful of counties, including Missoula County, are certified the same way for the unincorporated land outside city limits.
The state Building Codes Bureau, by default.
Everywhere else (any city or county that hasn't been separately certified) falls under Montana's Department of Labor & Industry, Building Codes Bureau, which issues and inspects permits directly rather than through a local building department.
Here's the part that trips people up: certification applies to a specific government, not a whole region. Gallatin County is a good example. The city of Bozeman is certified and runs its own building department. Step outside Bozeman's city limits into unincorporated Gallatin County, and you're no longer dealing with the city at all.
You're under the state Building Codes Bureau instead, because the county itself was never separately certified. Flathead County and Ravalli County work the same way: neither has its own building department, so state staff handle permits and inspections there directly, including for projects inside towns like Kalispell unless that specific municipality is separately certified.
Action:
Look up your property and confirm whether it sits inside city limits or in unincorporated county land, then check that specific government against the state's certified jurisdiction list. Don't assume based on what a neighboring county or a nearby town requires.
Step 2: Pull your property's actual record
Once you know who regulates your property, get the specifics of your lot before you plan around anything. Most certified jurisdictions maintain an online property lookup. Missoula County's Fast Facts tool is a good example: it will show your zoning designation, whether you're in a mapped floodplain or shoreline area, and your septic or well permit history.
This matters more than it sounds. A pool or an outdoor kitchen that's otherwise perfectly fine can still require floodplain review or a septic evaluation depending on where the lot sits relative to a drainfield or a waterway.
Step 3: Get the actual exemption list for your jurisdiction, not a general rule of thumb
Every certified jurisdiction publishes its own list of what's exempt from a building permit, and the thresholds are specific enough that guessing is a bad idea. As one real example, Missoula County exempts decks 30 inches or less from grade to the deck surface, small non-commercial sheds under 200 square feet, greenhouses and hoop structures for the owner's own residential use, and open-air, non-habitable additions like covered porches or lean-to storage.
Here's the detail that catches people off guard, though: pergolas and gazebos are classified under commercial building code in that same jurisdiction and are specifically carved out of the deck and patio exemption, even at a small residential scale. Bozeman, separately, treats decks and fences as their own stand-alone permit category with a published exemption document rather than folding them into general construction rules.
The point isn't to memorize any one jurisdiction's numbers. It's that you need to pull the actual current document for your specific city or county rather than relying on what applied somewhere else, or what applied last year.
Action:
Request or download the exemption list directly from your jurisdiction's building division before assuming any project, even a small one, is automatically exempt.
Step 4: Separate the "can I build it here" question from the "how do I build it" question
This is one of the most consistently misunderstood parts of the process. Even a structure that's fully exempt from a building permit can still require a zoning compliance permit or land use permit, confirming it meets setback, coverage, and use requirements for your specific zoning district, plus floodplain or shoreline permits if you're near water, and separate electrical, plumbing, or mechanical permits for the trade work involved.
In most jurisdictions these are reviewed by an entirely different department than the one that issues building permits: Planning, Development & Sustainability handles zoning and land use in Missoula County, for instance, while a separate Building Division handles construction permits. Getting a "no permit needed" answer from one office doesn't mean you're clear with the other.
Action:
Ask explicitly about zoning/land use compliance and any trade permits (electrical, plumbing, mechanical) even after you've confirmed the structure itself is exempt from a building permit.
Step 5: Call before you assume, and get it in writing
For anything that touches gas, electrical, plumbing, water, or a structure near a property line, wetland, or slope, a phone call to the building department is worth more than any guide, including this one, because they're working from the current version of the code and know your specific parcel.
In Missoula County, that's the Building Division at 406-258-3701 (option 2) for construction questions and Planning, Development & Sustainability at 406-258-4642 for zoning and land use.
For projects under direct state jurisdiction, the Building Codes Bureau can be reached through Montana's ebiz.mt.gov portal or the regional field office for your area. When the answer is anything other than an obvious yes or no, ask for it in an email so you have a record of exactly what you were told.
Step 6: Prepare your application materials
Once you've confirmed a permit is required, gather what the application will actually ask for:
A site plan showing the structure's location relative to property lines, setbacks, and existing structures.
Floor plans and elevation drawings for anything with walls or a roof.
Engineer-sealed structural details, most commonly roof truss specifications, for any roofed or enclosed structure, which applies to a fully covered outdoor kitchen or a four-season patio structure but generally not to a simple ground-level patio.
Any supporting documents specific to your project: manufacturer specs for a spa or swim spa, gas line routing for an outdoor kitchen, or a septic evaluation for a pool.
Step 7: Submit your application and pay the fees
Permit fees in most Montana jurisdictions are calculated from the estimated construction value of the project, using a standard cost-per-square-foot valuation table matched against a published fee schedule with value brackets.
As a real example of the mechanics: a project valued in a given bracket in Missoula County's fee schedule is assigned a flat fee tied to that bracket, so a small increase in project value can bump you into the next fee tier.
Projects issued directly through the state Building Codes Bureau also carry an additional plan review fee, currently 35% of the base building permit fee, that's specific to the state process and doesn't necessarily apply to a locally certified jurisdiction's own fee schedule. Ask your specific office for its fee calculator or published schedule rather than estimating from a different jurisdiction's numbers.
Action:
Get a written fee estimate before you commit to a design, especially for larger structures where the valuation-based fee can shift meaningfully with square footage.
Step 8: Track the plan review
Review timelines range from same-day for very simple, clearly conforming projects to several weeks for anything larger or more complex, and it depends heavily on the office's current workload.
If your plans come back with corrections, such as a missing setback dimension or an unclear truss spec, respond promptly, since most offices process resubmittals in the order received, the same as new applications.
Step 9: Schedule inspections at each required stage, not just at the end
A permit typically requires inspection at multiple points during construction, not a single sign-off when the work is finished. Depending on the project, that can include a footing or foundation inspection before it's covered, a framing inspection before drywall or siding goes up, rough electrical and plumbing inspections before those are enclosed, and a final inspection once everything is complete.
Missoula County, for example, allows inspections to be scheduled online with 24 hours' notice or by phone, and even offers a remote inspection option for roofing. Skipping an inspection stage, such as covering a footing before it's checked, is one of the most common and most expensive mistakes on owner-managed projects, because it can mean opening the work back up.
Action:
Get the full inspection sequence for your specific permit type in writing when the permit is issued, and schedule each one before you close in the work it covers.
Step 10: Get final sign-off and keep the paperwork
Once the last inspection passes, keep the final approval or certificate on file permanently, not just until the project wraps up. It's the document that answers an insurance adjuster's or a future buyer's question about whether the gas line, the electrical circuit, or the pool equipment was installed and inspected to code.
A closer look at what this means for our services specifically
With the general process covered, here's how it plays out project by project. For each one, ask the questions below in order. They'll tell you which permits are actually in play before you call anyone.
First: is a gas line being run to it? If yes, that's a mechanical permit, full stop. Second: is new electrical being run (outlets, lighting, a hood vent, a fridge)? That's an electrical permit. Third: does it have a roof or enclosed walls? If so, add a building permit to the list, plus engineer-sealed truss details if it's a solid roof. An open countertop-and-grill structure with no gas or electrical hookups is the one scenario that sometimes clears all three questions, but confirm that with your building department rather than assuming.
First question: is it being wired to a dedicated 240V circuit? In practice this is nearly always yes, and it nearly always means an electrical permit regardless of what the tub itself requires. Second: does it need a gas line for a heater, or new plumbing? Add mechanical or plumbing permits accordingly. Third: is it sitting on a new pad, deck, or patio? That structure gets evaluated on its own under Step 3's exemption rules. A spa itself isn't usually the trigger; the platform under it can be.
Assume all three apply until told otherwise: a building permit, zoning/land use compliance, and, critically for any property on a septic system, a septic evaluation to confirm the pool won't compromise the drainfield. Add floodplain or shoreline review if the lot is anywhere near mapped water. Montana treats a genuinely private, single-family pool differently than a public or commercial one for licensing purposes, but that distinction doesn't remove local building and zoning requirements. It only affects whether the pool needs to be licensed and inspected like a public facility.
Patios, decks, and hardscape.
First question: how high off grade is it? Low decks and ground-level hardscape, such as pavers, flagstone, or poured concrete with nothing attached above it, are the most likely exempt category across most jurisdictions, but the exact height cutoff is set locally, so confirm the number rather than assuming it matches what you've read elsewhere. Second question: is it structurally attached to the house? An attached deck is treated as a structural addition in most places and generally needs a permit regardless of height.
Pergolas and covered structures.
Don't extend the deck exemption to these by default. In at least one major Montana jurisdiction, pergolas and gazebos are explicitly classified under commercial building code and excluded from the residential deck and patio exemption, meaning a small, simple pergola can require a full building permit even where a deck of similar size and height wouldn't. Check this one specifically; it's the single most common surprise in this category.
Same first question as the outdoor kitchen: is gas involved? That's a mechanical permit. A larger built structure, a full masonry fireplace for instance, is more likely to also need a building permit than a small prefabricated or portable fire feature.
The trigger is almost always height. Taller fences (commonly in the 6- to 8-foot range, though the exact cutoff is set locally) typically require a building permit plus zoning compliance; shorter fences are more often exempt from the building permit itself but should still be checked against setback rules, especially on corner lots.
Mistakes that end up costing people the most
A few patterns come up again and again on owner-managed projects, and they're worth calling out directly:
Starting work before the permit is actually issued.
Most jurisdictions charge a real penalty on top of the standard fee if inspectors find work underway without an issued permit, in some cases scaled to how far along the work already is.
Assuming a rule from one jurisdiction carries over to another.
A deck height exemption, a fee schedule, or a septic requirement in one county doesn't transfer across a county line, or even across a city boundary within the same county.
Treating a pergola like a deck.
As covered above, this is the most common single mix-up we see.
Skipping the zoning or septic review because the structure itself is building-permit-exempt.
An exempt structure can still need a separate zoning or environmental health sign-off.
Not budgeting for the plan review fee on state-issued permits.
That 35% add-on catches people who priced only the base permit fee.
A short glossary, since the terminology isn't always intuitive
Building permit:
Covers the structure itself, including framing, roofing, and foundation.
Electrical, plumbing, and mechanical permits:
Separate, trade-specific permits that often apply even when the building permit doesn't (a hot tub's electrical circuit is the clearest example).
Zoning compliance or land use permit:
Confirms the project meets setback, use, and coverage rules for your zoning district; issued by planning staff, not the building department.
Floodplain or shoreline permit:
Required for work near mapped water, regardless of whether the structure itself needs a building permit.
Septic evaluation:
Confirms new construction, especially a pool, won't compromise an existing drainfield.
Frequently asked questions
What happens if I build without a required permit?
Beyond the penalty fees described above, unpermitted work can complicate a future sale, since buyers' inspectors and title companies commonly ask about permit history, and it can affect whether an insurance claim tied to that work is honored.
Does the answer change if I'm hiring a licensed contractor?
The permit still has to be pulled and inspected either way. A licensed contractor doesn't exempt the project from the process, though a contractor who regularly pulls permits in your jurisdiction will usually know its specific exemption thresholds without having to look them up.
Who's actually responsible for getting the permit: me or the contractor?
In Montana's state-administered system, the property owner is formally responsible for the permit even when a contractor manages the application on their behalf, which is one more reason to keep a copy of everything for your own records rather than relying solely on the contractor's file.
My project is small. Does any of this really apply?
Small is relative to the thresholds, not to your own sense of scale. A pergola well under 100 square feet can still trigger a full building permit in a jurisdiction that classifies it commercially, while a much larger ground-level patio next door might need nothing at all. This is exactly why Step 3 matters more than intuition.
Where we fit into this process
As your contractor, we pull the required permits ourselves as part of any project we build, and we've been through this process enough times in enough jurisdictions to know where the real gotchas are: the pergola classification, the septic evaluation for a pool, and the difference between what a city and its surrounding county each require.
Working through this guide yourself isn't about replacing that. It's about knowing enough going in to ask sharp questions, understand why a permit timeline adds a few days to the front of a project, and avoid designing something around an assumption that turns out to be wrong for your specific address. If you're planning a project and want to know exactly what it will take before the design is finalized, that's a conversation we're glad to have early.
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