Bolthole Index

Lincoln County, Montana

Building permits, zoning and septic rules in Libby, Montana

Libby, Montana requires city building permits for home construction and many alterations inside city limits.1 Libby administers municipal zoning, while Lincoln County Environmental Health handles non-public septic systems and the county Floodplain Manager issues separate floodplain permits where required.234 Libby’s overnight residential camping exception is conditional, so do not treat private land as automatic permission for ongoing RV living.5

At a glance

Building permits
City building permit required for new homes and covered alterations; listed exemptions apply1
Zoning
City zoning; lot dimensions and uses depend on the district2
Septic permits
Lincoln County Environmental Health; local wastewater permit required before installation36
RV camping
Camping generally prohibited, with a conditional overnight exception on private residential property5
Accessory dwellings
Permitted with city approval; framed construction and permanent foundation required7
Minimum home size
700 square feet per dwelling in the Agricultural-Suburban District8
Floodplain
Separate Lincoln County Floodplain Manager permit for covered work in a FEMA-regulated floodplain4

Who to call

Building permits

City of Libby Building Department

City residential building applications, plan review, inspections and questions about permit exemptions.

406-291-9629

[email protected]

Online permits →

Planning & zoning

City of Libby Planning and Zoning

Municipal zoning map, zoning ordinance and planning-related questions.

Septic permits

Lincoln County Environmental Health Services

Non-public wastewater permits, site evaluations, system design and existing septic records.

Septic permits

Lincoln County Health Department

Telephone contact for Environmental Health and septic-record questions.

283-2442

Contact details are copied from each office’s official page and were checked against it on October 11, 2026.

Off-grid gear

Going off-grid in Libby means bringing your own water and power. The kit we’d start with:

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Do you need a building permit in Libby, MT?

Libby requires a city building permit before new home construction and covered work such as additions, remodels, detached garages, decks, demolition or occupancy changes.1 The city applies adopted building codes and performs residential plan reviews and inspections.910 Electrical, plumbing and mechanical work require separate state permits.1

Some work is exempt from a city building permit, but ask the Building Department whether your exact project qualifies before starting.1 The agricultural exemption identified by Libby covers shade-cloth nursery or agricultural structures, excluding service systems; exempt work must still comply with city code.11

Who issues building permits in Libby, and what do applications cost?

For residential building permits inside Libby, contact the City Building Department at 406-291-9629 or [email protected].12 Obtain the application from the building inspector, city hall or city website.13 Libby’s application calls for the work and land identification, intended use and occupancy, construction documents, project valuation and a signature, plus information requested by the inspector.13

Libby bases building-permit fees on overall project valuation, rather than a single flat charge for every home.14 Applications are valid for 180 days; written extensions of up to 90 days each may be granted for justifiable cause.13 Ask the inspector to confirm the fee and inspection schedule for your submitted plans.1410

Does Libby have zoning, lot-size rules and setbacks?

Libby administers its own zoning ordinance and zoning map; the district controls which dimensional rules apply to a parcel.215 The city contracts with a professional planner through WWC for planning-related needs.16

Libby’s Residence A District requires at least 6,000 square feet of lot area for each dwelling.17 The Agricultural-Suburban District requires at least 1 acre and a lot width of at least 150 feet, with lot area also dependent on soil, groundwater and other development limitations.18 Agricultural-Suburban minimum yards are 35 feet in front, 25 feet at the rear and 25 feet on each side; principal and accessory buildings together may cover no more than 15% of the lot.1920 Use the parcel’s actual district rather than applying Agricultural-Suburban rules across Libby.2

How do septic permits work inside Libby?

Lincoln County Environmental Health Services handles non-public septic permitting in Lincoln County, and a local wastewater treatment system permit is required before installation.36 Libby also restricts private wastewater disposal: a system using subsurface soil absorption cannot receive a permit on a lot smaller than 20,000 square feet.21 A lot that satisfies Libby’s Residence A zoning minimum therefore does not necessarily satisfy the city’s private-wastewater minimum.1721

County septic site evaluations must be performed by a Qualified Site Evaluator, and systems must follow DEQ Circular 4.6 The homeowner exception for constructing a gravity system on the homeowner’s own residential property concerns the installer license; the local wastewater permit remains required.6 If an existing septic permit does not appear in the county’s online lookup, ask the Health Department to confirm the record.22

Can you live in an RV or tiny home in Libby?

Libby generally prohibits camping on public or private property, but allows overnight camping on private residential property with the owner’s or lawful possessor’s consent when it creates no health, safety, welfare or nuisance problem and violates no other city-code provision.5 That conditional overnight exception does not establish blanket approval for ongoing RV occupancy; ask City Planning and Zoning about your proposed duration and use before relying on an RV while building.516

Libby allows an accessory dwelling on a parcel containing a single-family dwelling, subject to city permitting, framed construction and a permanent foundation.7 Attached or detached ADUs are capped at 75% of the main dwelling’s gross floor area or 1,000 square feet, whichever is less.7 Agricultural-Suburban dwellings have a 700-square-foot minimum.8 We could not confirm a separate Libby tiny-home occupancy rule; ask the Building Department and city planning office which dwelling category your design fits.1216

Building a home in Libby: what are the steps, in order?

  • Start with City Planning and Zoning: identify the parcel’s district and check your proposed dwelling, lot dimensions and site layout against that district.2
  • Resolve wastewater design with Lincoln County Environmental Health if proposing a private system, including Libby’s soil-absorption lot-area restriction.321
  • Submit the signed building application, construction documents, intended occupancy and valuation to the city building inspector.13
  • Obtain a separate Lincoln County Floodplain Manager permit when covered construction falls within a FEMA-regulated floodplain; floodplain fees are additional to the city building-permit fee.4
  • Obtain the required state electrical, plumbing and mechanical permits, and arrange the city’s residential inspections as work progresses.110

For land beyond city limits, use the Lincoln County guide: the county’s single-family residential building-permit exemption applies to unincorporated land outside certified local building-code jurisdiction.23

Watch-outs

  • Before remodeling in Libby, request property cleanup information through the Property Evaluation Notification form or Lincoln County Asbestos Resource Program; the city warns that vermiculite insulation may contain asbestos.12
  • Libby’s Residence A lot-area minimum does not override the larger minimum for a private wastewater system using subsurface soil absorption.1721
  • We could not confirm a Libby owner-builder building-permit exemption or the city’s certificate-of-occupancy procedure; ask the City Building Department before beginning work or moving in.12

Sources

  1. Building Inspector – City Of Libby, MT (Libby), quoted and re-checked
  2. Planning and Zoning – City Of Libby, MT (Libby), quoted and re-checked
  3. Septic Permitting, quoted and re-checked
  4. Building Permit Requirements and Application (Libby), quoted and re-checked
  5. Libby Municipal Code, Title 9, Section 9.46.020 (Libby), quoted and re-checked
  6. Septic Permitting, quoted and re-checked
  7. Libby Municipal Code, Title 17, Section 17.29.010 (Libby), quoted and re-checked
  8. Libby Municipal Code, Title 17, Section 17.19.030 (Libby), quoted and re-checked
  9. Building Inspector – City Of Libby, MT (Libby), quoted and re-checked
  10. Building Inspector – City Of Libby, MT (Libby), quoted and re-checked
  11. Building Permit Requirements and Application (Libby), quoted and re-checked
  12. City of Libby Building Department (cityoflibby.com)
  13. Building Permit Requirements and Application (Libby), quoted and re-checked
  14. Building Inspector – City Of Libby, MT (Libby), quoted and re-checked
  15. Planning and Zoning – City Of Libby, MT (Libby), quoted and re-checked
  16. City of Libby Planning and Zoning (cityoflibby.com)
  17. Libby Municipal Code, Title 17, Section 17.12.030 (Libby), quoted and re-checked
  18. Libby Municipal Code, Title 17, Section 17.19.020 (Libby), quoted and re-checked
  19. Libby Municipal Code, Title 17, Section 17.19.040 (Libby), quoted and re-checked
  20. Libby Municipal Code, Title 17, Section 17.19.030 (Libby), quoted and re-checked
  21. Libby Municipal Code, Title 13, Section 13.02.280 (Libby), quoted and re-checked
  22. Lincoln County Environmental Health Services (lincolncountymt.us)
  23. bsd.dli.mt.gov, quoted and re-checked

Written October 11, 2026 from the rules quoted below, each taken from an official source and re-checked by an independent reviewer. This is research, not legal advice: rules change, so confirm with the office before you buy or build.

Answers from the rulebook for Libby

Libby’s own rules

  • Building permitRequired

    New construction, remodels, additions, alterations, improvements, detached garages, decks, storage sheds, demolition, and occupancy changes inside Libby city limits.

    • The city page lists permit exemptions including some small sheds, fences, retaining walls, finish work, and other listed work.
    • State permits are separately required for electrical, plumbing, and mechanical work.
    “Any property owner or contractor who intends to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure, or to cause any such work to be performed, shall first make application to the building inspector, and obtain the required building permit.”
  • Building code adoptedAdopted

    Buildings within Libby city’s building-code enforcement area.

    • The city adopts the most current state-directed International Building Code, International Residential Code, Uniform Code for Building Conservation, International Existing Building Code, and International Swimming Pool and Spa Code.
    • The city page separately identifies the 2021 International Residential, Energy Conservation, Existing Building, and Swimming Pool and Spa Codes.
    “The current codes that the City of Libby has adopted:”
  • InspectionsRequired

    Residential building projects and sidewalks/driveways inside Libby city limits.

    • The city building department performs plan reviews and inspections on all residential building projects.
    • The city page states sidewalks and driveways are exempt from permits but inspection is required.
    “INSPECTION RECORD (IBC-IRC requires the permit holder to notify the building inspector when work is ready for inspection)”
  • Local zoningPresent

    Land inside Libby city limits; the city administers its own Title 17 zoning ordinance and zoning map.

    • The City of Libby planning page identifies Title 17 of the Municipal Code as the Zoning Ordinance.
    • District-specific use and dimensional rules apply.
    “Zoning Ordinance (Title 17 of Municipal Code)”
  • Zoning districtsPublished

    Zoning districts inside Libby city limits.

    • The official zoning map is adopted by reference as part of Title 17.
    • The listed districts are Residence A, Residence B, Medical Community, Agricultural-Suburban, Business-Residence, Main Business, and Industrial.
    “City of Libby Zoning Map (March 23, 2021)”
  • Camping on your landLimited

    Camping on public or private property inside Libby city limits.

    • Camping on public or private property is unlawful and a public nuisance.
    • Exception: overnight camping on private residential property with consent of the owner or lawful possessor, if it does not threaten health, safety, or welfare, create a nuisance, or contradict another Libby Municipal Code provision.
    • Special-event camping may be authorized; lawful day use on public property may be authorized.
    “It is unlawful and a public nuisance for any person to camp, occupy camp facilities, or use camp paraphernalia in the following areas: 1. Any public property; or 2. Any private property.”
  • Accessory dwellingsAllowed (with conditions)

    One ADU on a lot or parcel containing a single-family dwelling inside Libby city limits.

    • The ADU must be framed and on a permanent foundation.
    • A detached or attached ADU may not exceed 75 percent of the single-family dwelling’s gross floor area or 1,000 square feet, whichever is less.
    • No additional parking is required.
    • All ADUs are subject to city permitting.

    maximum detached or attached ADU size: <= 75 percent of single-family dwelling GFA (Alternatively, maximum 1,000 square feet, whichever is less.)

    “One accessory dwelling unit (ADU) shall be permitted on a lot or parcel that contains a single-family dwelling.”
  • Off-grid sanitationLimited

    Private wastewater disposal inside Libby city limits.

    • Construction of privies, septic tanks, cesspools, or other wastewater-disposal facilities is unlawful except as provided by city code.
    • Permitted private systems must comply with state Department of Public Health recommendations and cannot use subsurface soil absorption on lots under 20,000 square feet.

    minimum lot area for subsurface soil absorption: >= 20000 square feet (No permit shall be issued for a private wastewater system employing subsurface soil absorption where the lot is less than 20,000 square feet.)

    “No permit shall be issued for any private wastewater disposal system employing subsurface soil absorption facilities where the area of the lot is less than twenty thousand square feet.”
  • Agricultural exemptionConditional

    Shade-cloth structures for nursery or agricultural purposes inside Libby city limits.

    • The city permit materials exempt shade-cloth structures constructed for nursery or agricultural purposes, but not their service systems.
    • City code must still be followed even for listed permit-exempt work.
    “Shade cloth structures constructed for nursery or agricultural purposes, not including service systems.”
  • Subdividing landRegulated (with conditions)

    Subdivision and development inside Libby city limits.

    • City Design and Construction Standards require new development or redevelopment to comply with adopted Subdivision Standards.
    • Development consisting of more than one dwelling unit is assessed the city’s actual outside-planning-consultant cost; additional invoicing may apply if review exceeds the fee schedule.
    “The city Design and Construction Standards require that any new development or redevelopment comply with adopted Subdivision Standards.”
  • Permit feesPublished (with conditions)

    City building permits and subdivision review inside Libby city limits.

    • Building permit fees are based on total project valuation.
    • The city PDF lists valuation tiers from $1 through $5,000,000 and over.
    • Subdivision fees include minor, major, exemption, environmental-health, final-plat, and mobile-home/RV/condo-development-variance fees.

    building permit fee for valuation $1-$500: 24 USD · first minor subdivision fee: 500 USD · major subdivision fee: 800 USD (Plus $50 per lot.)

    “The cost for a building permit is based on the overall cost for the project according to the permit fee scale below.”
  • Permit processPublished (with conditions)

    Building-permit applications inside Libby city limits.

    • The applicant obtains the application from the building inspector, city hall, or city website.
    • The application must identify the work and land, state intended use and occupancy, include construction documents, state valuation, be signed, and provide other information requested by the building inspector.
    • An application is valid for 180 days; written extensions may be granted for additional periods not exceeding 90 days each with justifiable cause.

    application validity: 180 days (Extensions may not exceed 90 days each.)

    “To obtain a permit, the applicant shall first get an application from the building inspector, city hall, or from cityoflibby.com.”

Rules another office applies inside Libby

Libby does not set these itself; the county, a health district or the state does, and they apply to every address inside its limits.

  • Minimum dwelling sizeDistrict specific (with conditions)

    Each dwelling unit in Libby’s Agricultural-Suburban (A-S) District.

    • The cited minimum applies in the A-S District.

    minimum dwelling floor area: >= 700 square feet

    “Each dwelling unit shall have a minimum of seven hundred (700) square feet of floor area.”
  • Minimum lot sizeDistrict specific (with conditions)

    Lots in Libby’s Agricultural-Suburban District.

    • Lot area is determined by soil, groundwater, and other urban-development limitations.
    • The minimum is one acre; A-S-1 denotes one acre, A-S-2 denotes two acres, and so on.

    minimum lot area: >= 1 acre · minimum lot width: >= 150 feet

    “Under no circumstances shall the lot area be less than one acre with a lot width not less than one hundred fifty (150) feet.”
    One more reviewed finding on this topic
  • SetbacksDistrict specific (with conditions)

    Lots in Libby’s Agricultural-Suburban District.

    • Animal pens, coops, barns, stables, and permanent corrals must be at least 100 feet from residences or public roads and at least 50 feet from property lines.

    front yard: >= 35 feet · rear yard: >= 25 feet · side yard each side: >= 25 feet

    “Every lot in the A-S District shall have the following minimum yards: Front yard 35 feet Rear yard 25 feet Side yards 25 feet each side.”
  • Lot coverageDistrict specific (with conditions)

    Principal and accessory buildings in Libby’s Agricultural-Suburban District.

    • The combined principal and accessory building coverage may not exceed 15 percent of lot area.

    maximum lot coverage: <= 15 percent

    “In the A-S District, not more than fifteen percent (15%) of the lot area shall be occupied by the principal and accessory buildings.”
  • Building in a floodplainRequired

    New construction, additions, or remodels inside Libby city limits when the property lies within a FEMA-regulated floodplain.

    • A separate permit is issued by the Lincoln County Floodplain Manager.
    • Floodplain fees are in addition to the city building permit fee.
    • Applications are available at the Lincoln County Annex.
    “If the property lies within a FEMA regulated floodplain, a separate permit will be issued by the Lincoln County Floodplain Manager.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Libby or Lincoln County directly.

  • Owner-builder exemption — Owner-builders constructing inside Libby city limits.
  • Certificate of occupancy — Buildings inside Libby city limits.
  • Building height — Buildings inside Libby city limits.
  • Tiny homes — Tiny-home occupancy inside Libby city limits.
  • Septic permit — Private septic or other private wastewater systems inside Libby city limits.
3 more unanswered
  • Septic inspection
  • Well permit
  • Short-term rentals

Each answer was extracted from an official source and independently re-checked against that source by a second reviewer. That is an evidence check, not legal advice. Rules change; confirm with the authority before you buy or build.

Unanswered questions are usually a sign that Libby publishes no rule on the point, not that none exists. Lincoln County’s page lists the county offices to call.

← All of Lincoln County: county rules, score and offices