Fergus County, Montana Building Permit Guide

Fergus County is not a certified building-code jurisdiction, so it issues no building permit. What it does require is a Development Permit from the Planning Office at 712 West Main Street, Lewistown: $50 before construction, $500 if work has already begun, with about 30 working days for processing. The permit flags road, floodplain and septic issues and assigns the physical address. Inside Lewistown the City’s Building Department issues building permits; in the rest of the county the State permits commercial buildings and a house with fewer than 5 units needs none.

What needs a permit in Fergus County?

The County’s own form puts it plainly: anyone proposing to build a residential or commercial structure in Fergus County should first obtain a Development Permit. The form asks for all proposed construction, including outbuildings. The permit exists to catch property, road and floodplain limitations before work starts and to give the structure an address for emergency services.

The Planning Office uses the application to decide which of these other approvals the project needs:

• Floodplain permit, for work in the designated floodplain under the County’s Floodplain Hazard Management Regulations.
• Septic permit from the County Sanitarian. A Development Permit has to be completed before a septic permit application can be approved.
• Rights-of-way construction permit, for a new or altered approach or utility work in a county road right-of-way.
• Buildings for lease or rent review, which has its own permit fee.

For the building code, the form tells applicants to contact the state Building Codes office about state permits for all building in the county. Outside Lewistown that means a state building permit for commercial buildings and residential buildings of 5 or more units; smaller houses, farm and ranch buildings and private garages are exempt from it.

Who issues permits in Fergus County?

Planning and the Sanitarian share Suite 101 of the courthouse and one phone number, so a project usually starts there.

The 5 incorporated places:

• Lewistown (population 6,179): the only certified jurisdiction in the county, for building, inside city limits. Applicants bring their documents to the Building Department, the permit is issued once the plans are approved, and the contractor needs a valid City business licence. The City’s Building Department page lists the 2021 edition of the building codes; the State’s 2024 editions took effect on September 26, 2026, and state rules give a certified city 90 days from the State’s notice to adopt them. Under the City Code the building inspector checks zoning before issuing any building permit, and the zoning title carries the City’s floodplain regulations. The City Code applies zoning inside the city limits, while the Planning Department (406-535-1775) describes its zoning work as covering the city and the 2 miles around it. Trade permits remain with the State.
• Denton (population 207): not certified. The Town says construction, improvements and signs may need a permit when the property is in the floodplain or under a land use agreement, and its clerks hand out the land use application. The Town office is at 515 Broadway Avenue (406-567-2571), open Monday to Friday, 9:00 a.m. to 4:00 p.m.
• Moore (population 203): not certified, but the Town Code’s zoning chapter requires a permit from the Town Council before a building or structure is erected, reconstructed, structurally altered, enlarged or moved. The application needs a plat drawn to scale showing the lot and the building. The Town Clerk also serves as floodplain administrator and is in the office at 201 W Fergus Avenue, Suite 2, on Wednesdays and Thursdays (406-374-2480).
• Winifred (population 178) and Grass Range (population 114): neither is certified, so the state rules apply to building there. The published sources do not say whether either town requires a permit of its own. Winifred’s town office is on 406-462-5425 and Grass Range’s on 406-428-2174.

Planning questions near Lewistown go to a separate City-County Planning Board, which has jurisdiction over the city and a 4.5-mile area of the county around it.

Fergus County applications

None of the County applications is filed through a portal. Each is a PDF returned to Suite 101 with its fee.

• Development Permit Application Form: a 2-page form with a sample site plan on the cover. Planning staff mark on it whether a floodplain permit, septic permit or approach permit is needed, then record the address assigned.
• Rights of Way Construction Permit Application: for new construction, alteration of an existing encroachment or utility work, returned to the Planning Office.
• Site Visit Request and Septic Permit Application: one form for the County site evaluation and the permit, followed by an As-Built form when the system is in.
• Certified installer and certified site evaluator applications: for contractors who want County certification.

Environmental Health fees can be paid online, with a service fee added ($6 on the $200 permit). In Lewistown, the Building Department posts residential and commercial building permit requirements, its Standards for Design and Construction and a Development Review Checklist.

Fergus County fees

Planning fees are from the Planning Office Fee Schedule approved in January 2026, where every fee is non-refundable. Septic fees are from the Environmental Health schedule dated December 11, 2025 and the current septic application.

The septic application combines the permit and the County site evaluation: a new system is $475 with a certified installer or $925 if the owner installs it, and those totals drop to $200 and $650 when someone else supplies the site evaluation. The County evaluates sites for single-family residential systems only.

Electrical, plumbing and mechanical permits

The Development Permit form lists one number, 406-841-2056, for state building, electrical, plumbing and mechanical permits and inspections, and that covers the trades throughout Fergus County. Lewistown’s certification is for building alone, so electrical and plumbing permits for work in the city are also taken out with the State.

What to prepare

A right-of-way application needs a plot plan or map, with the site flagged or staked.

How to apply: Fergus County steps

Processing times and inspections

The Planning Office gives a 30-working-day processing period, weather permitting, for a Development Permit filed before construction, and 30 to 60 working days for one filed after the fact. Staff visit the site to collect the staked locations; if no stakes are visible the applicant gets one courtesy call, and the address is not released until any repeat-visit fees are paid.

A permit to construct a septic system is valid for 12 months from issue, and the Sanitarian is usually in the field on Wednesdays and Thursdays. Work in a county right-of-way has to be done to the satisfaction of the County’s representative, with $20 billed for each inspection after the first.

The County does not inspect buildings. State inspectors cover state-permitted work, and the Lewistown Building Department covers permits it issues.

Local details that matter

Two planning boards: the 5-member County Planning Board meets on the second Thursday of the month when it has business, and the 9-member City-County Planning Board meets on the third Thursday as needed.

Addresses: the Planning Office assigns every new physical address in the county and passes it to Central Montana Dispatch and the local post office. While doing so it checks whether the development needs septic service or sits in the special flood hazard area.

Utilities and water: the Development Permit form lists Fergus Electric Cooperative (406-538-3465) and NorthWestern Energy new construction (800-371-8666) for service, and the DNRC on 406-538-7401 for water rights and well information.

The Road Book: the Planning Office sells a township-by-township book of county roads and landowners for $50, cash or check.

Montana building code

Montana adopts one building code, based on the 2024 International Codes from 26 September 2026; a certified local program or the state Building Codes Program enforces it, and the state code does not reach houses of fewer than five units, farm and ranch buildings or private garages unless a local government has made it apply to them. How Montana’s statewide code works

Official permitting resources for Fergus County

These are the primary sources behind this guide. Codes, fee schedules and procedures change — confirm the position for your filing date.

• Montana effective construction code editions
• Montana certified local building programs
• Montana DLI state building permit application
• Fergus County Environmental Health (Sanitarian): septic permits
• Fergus County Planning Office
• Fergus County Development Permit Application Form
• Fergus County Planning Office Fee Schedule (January 2026)
• Fergus County addressing and GIS services
• Fergus County floodplain programs
• Fergus County Rights of Way Construction Permit Application
• Fergus County Site Visit Request and Septic Permit Application
• Fergus County Environmental Health fee schedule
• City of Lewistown Building Department

Fergus County permit FAQs

Do I need a building permit for a house in Fergus County?

Not a building permit, outside Lewistown, if the building has fewer than 5 dwelling units. You do need the County’s $50 Development Permit before construction, and a septic permit if the house will have its own system.

What happens if I build before getting the Development Permit?

The fee rises from $50 to $500, and processing can take 30 to 60 working days instead of 30.

How much is a septic permit in Fergus County?

$200 with a certified installer or $650 if you install it yourself, plus $275 if the County does the site evaluation. That makes $475 or $925 for a new system with a County evaluation.

How do I get an address for a new house?

Through the Development Permit. The Planning Office assigns the address once it has located the staked driveway and building site.

Who issues building permits in Lewistown?

The City of Lewistown Building Department, 308 4th Avenue South, 406-535-1776. Your contractor needs a City business licence.

Do I need a permit for a driveway onto a county road?

Yes, a Rights of Way Construction Permit, with a $50 inspection fee ($100 after the fact). Approaches onto state highways go through the Montana Department of Transportation.

What does a floodplain permit cost in Fergus County?

Floodplain review is $500, with another $250 if construction starts before the review.

Simplify Fergus County permitting with Alliance Permitting

Alliance Permitting is a permit documentation and submission company in Montana. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.

This guide is provided by Alliance Permitting for general information about Fergus County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.