Lewis and Clark County, Montana Building Permit Guide

On the state list of certified building-code jurisdictions, Helena (447-8438) and East Helena (594-6322) run programs for their city limits only; Lewis and Clark County is not certified, and all other areas are under the State Building Codes Bureau. That area held 37868 of the county’s 75331 residents by the Census Bureau’s Vintage 2025 estimate.

This guide covers the state and county permits outside the two cities, and Helena’s Building Division. The county checklist and the state bureau list different state phone numbers; both are given below.

What requires a permit in Lewis and Clark County?

The county’s construction checklist for building outside city limits says a state building permit is required for all non-residential construction, a state plumbing permit for residential work done by a contractor and for all non-residential work, and a state electrical permit for all construction.

County permits also apply: a Floodplain Permit for any construction in a Special Flood Hazard Area (development within the floodway is prohibited), an Approach Permit for every road approach onto a county or public road, an Excavation Permit for digging in a county or public road right-of-way or easement, and an Encroachment Agreement for encroachments into county rights-of-way. A county address is needed before a septic permit can be issued.

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

Who handles permitting in Lewis and Clark County?

CDP processes county permit applications and fees outside city limits and acts as liaison between the applicant and other county departments. The state’s office address and phone above come from its building-codes pages; confirm the number to call with the state.

County roads, addresses and zoning

Road approaches and excavation

Under the 2023 County Public Works Manual, an Approach Permit is needed before construction, and the approach must be built by a Certified Approach Installer; on hard-surfaced roads the approach must be hard-surfaced for at least 15 feet from the roadway. Excavation Permits are reviewed by Public Works, and Encroachment Agreements are approved by the Public Works Director.

Addresses

County address applications, for parcels outside Helena and East Helena, need the form, a copy of the filed certificate of survey or deed, and the fee.

Rental buildings

Buildings for Lease or Rent review is required when 4 or more rental buildings go on one tract.

Floodplain

Floodplain Permits are applied for on the Joint Application Form under the county floodplain ordinance, which took effect November 11, 2022.

Lewis and Clark County permit costs and fees

Where the state issues the permit, the fee follows a valuation table and plan review is 35 percent of the permit fee; a certified local program sets its own schedule. Montana’s state permit rules

How to get a permit in Lewis and Clark County

Where the state issues the permit, plan review averages about three weeks, and the building permit must be issued before any trade permit. Montana’s state permit rules

Building permits in Helena

Helena (35138 residents in the Vintage 2025 estimate) runs its City Building Division at 316 N. Park Avenue, Room 435, open Monday - Friday 9:00 a.m. to 4:00 p.m. Building permits, planning cases and inspection scheduling run through the Civic Access portal, and fees can be paid by card, cash or check. East Helena (2325 residents) has its own certified program.

Official Lewis and Clark County permitting resources

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

• Lewis and Clark County CDP permits
• County construction checklist
• County fee schedule (October 1, 2025)
• Lewis and Clark Public Health, Environmental Health
• Helena Building Division
• Montana Building Codes Program
• Montana DLI list of certified building-code jurisdictions

Frequently asked questions

Does a house outside Helena need a state building permit?

The county checklist says state building permits are required for all non-residential construction; a state electrical permit is required for all construction, and a state plumbing permit when a contractor does residential work.

Do I need an address before a septic permit?

Yes. Outside Helena and East Helena, a county address is required before a septic permit is issued; the fee is $25 including the plaque.

Which number reaches the state building program?

The bureau lists (406) 841-2056; the county’s construction checklist lists (406) 841-2040. Confirm with the state.

Simplify Lewis and Clark County permitting with Alliance Permitting

• Confirm whether Helena, East Helena or the state and county handle the parcel
• Prepare the state permits and the county address, approach, floodplain and septic applications
• Track each permit through to final

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 Lewis and Clark County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.