Bolthole Index

Lemhi County, Idaho

Building permits, zoning and land rules in Lemhi County, Idaho

64Index Score / 100
#17 of 44 in Idaho

Lemhi County, Idaho requires a building permit for construction, backed by complete building plans, a plot plan and a septic permit.1 The Lemhi County and City Building Department issues building permits and enforces the adopted codes, while the county sets zoning for unincorporated land.23 Septic permits are separate: Eastern Idaho Public Health issues them and inspects the installed system, not the building department.4

At a glance

Building permit
Required for building construction in Lemhi County5
Zoning
County zoning applies; the Salmon Area of City Impact also follows the city code36
Septic
Permit and inspection through Eastern Idaho Public Health478
RV living
Private-land occupancy rule not confirmed; ask the Building Department9
Tiny home
No separate countywide tiny-home rule confirmed; zoning and building review still matter105
Owner-builder
Idaho homeowner exemption allows an owner to permit and perform work on a primary or secondary residence11
Minimum lot size
Varies with zoning, utilities, geography and groundwater conditions12
Private well
An IDWR drilling permit is required before drilling13

Who to call

Building permits

Lemhi County and City Building Department

County building permits, planning and zoning, adopted-code enforcement and land-use questions

208-742-1703

200 Fulton Street, Suite 204, Salmon, ID 83467

Septic permits

Eastern Idaho Public Health — Lemhi County Office

Onsite wastewater applications, site evaluations, septic permits and inspections for Lemhi County

(208) 756-2123

801 Monroe, Salmon, ID 83467

Contact details are copied from each office’s official page and were checked against it on October 9, 2026.

Off-grid gear

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

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Do you need a building permit in Lemhi County, Idaho?

Yes. Lemhi County requires a building permit application, complete building plans and a plot plan for building construction, and a septic permit is required when building in the county.14 Work cannot begin and inspections will not be performed until the building permit has been issued.5

The county enforces adopted building regulations, including the Idaho Residential Code 2020 Edition, which consists of specified parts of the 2018 International Residential Code with Idaho amendments.215 Electrical, plumbing and HVAC permits are obtained through the Idaho Division of Occupational and Professional Licenses.14

A qualifying agricultural building may receive a permit exemption only when it is used solely for eligible agricultural purposes and the Assessor determines the land is actively devoted to agriculture.16 That exemption does not cover human habitation, public use, repair shops or personal-vehicle garages and storage, and the building must still satisfy county placement plus applicable snow and wind standards.16

Who issues building permits in Lemhi County?

The Lemhi County and City Building Department handles county building permits from its office at 200 Fulton Street, Suite 204 in Salmon; call 208-742-1703.9 The department assists with land-use questions, checks compliance with existing regulations, enforces adopted building codes and provides emergency addressing.9

Start with the department before ordering plans because the required documents can depend on the project. Lemhi County’s published process calls for a permit application, complete building plans, a plot plan showing the proposed building location and a septic permit for county construction.14 The plot plan should be resolved before site preparation because county setbacks vary with road frontage, lot position, wall height and special locations such as stream corridors.17

Inspections must be requested 24 hours in advance, and no work may be covered or go beyond the inspection point until it is inspected.18 Required stages include footings, stemwalls, concrete slab, framing, insulation, interior wall finishing and the final inspection; a re-inspection costs $47.18 Ask the Building Department for the permit fee schedule, which we could not confirm.9

Does Lemhi County have zoning?

Yes. Lemhi County has an official zoning map, zoning districts and district-specific standards and uses.319 Within the Salmon Area of City Impact, both the Salmon Development Code and Lemhi County Development Code apply, with the more restrictive provision controlling when they conflict.6

Lot size is not one countywide figure. Minimums vary with zoning, site characteristics, central water or sewer availability, groundwater vulnerability and named planning areas.12 Newly created lots require at least 110 feet of frontage; the code identifies a basic one-acre minimum but provides different minimums for serviced land and groundwater-vulnerability areas.12

County permit materials also specify setbacks and tell applicants to verify the applicable distance before preparing the site.17 A parcel review should therefore identify the zoning district, any overlay, legal lot status, access, utilities and the precise setbacks rather than assuming that rural acreage is unrestricted.

How do septic permits work in Lemhi County?

Eastern Idaho Public Health administers septic permitting in Lemhi County from its Salmon office at 801 Monroe; call (208) 756-2123.20 The district reviews wastewater applications, performs onsite evaluations, issues permits and conducts inspections.4

A valid installation permit is required before constructing, modifying or repairing an individual or subsurface sewage system, subject to limited exceptions for certain piping or mechanical repairs.7 An Environmental Health Specialist must inspect the installed system before it is covered, and a system covered prematurely must be uncovered.8

Soils deserve early attention: only about 4.4% of county soils are rated without severe limitations for a conventional septic drain field.21 Treat that as a screening signal, not a parcel verdict; the district’s site evaluation determines what can be permitted. Where public or central wastewater treatment is reasonably accessible, Idaho’s rules allow the permitting authority to deny an onsite septic permit.22

Can you live in an RV or tiny home in Lemhi County?

The county's guidance says temporary recreational lodging is the only legal use of an RV, and RV placement and occupancy are regulated by local planning and zoning rules.23 We could not confirm a rule that allows living in an RV on private land during construction, so before relying on one, ask the Building Department how the parcel’s zoning district treats occupancy, whether a permit is needed and what approved sanitation must be in place. Requirements for RV parks do not answer that private-parcel question; RV parks must have ready access to water, sewerage and electricity services.24

A tiny home is not automatically outside the permit system: the county says every dwelling, including a tiny house, must fit one of its classifications, and a tiny house classified as an RV may face planning and zoning approval challenges.25 Site-built and modular buildings must meet the building code's minimum area, described as about 150 square feet.25 Building permits and district zoning standards apply.519 We could not confirm a separate countywide minimum dwelling floor area, so ask the Building Department to review the proposed structure, foundation, use and zoning district.

Manufactured or mobile homes used as permanent single-family dwellings are allowed only under stated conditions: qualifying construction standards, removal of the hitch, wheels, chassis and running gear, attachment to a permanent foundation, and permanent utility connections.26 Every manufactured-home installation must also be inspected and approved by the state or authority having jurisdiction before occupancy.27

Building a home in Lemhi County: what are the steps?

  1. Ask the Building Department to identify the zoning district, overlays, setbacks and required submittals for the parcel. County zoning and development standards vary by district and planning area.19
  1. Confirm that Eastern Idaho Public Health can approve an onsite wastewater system before fixing the house site. The district performs site evaluations and issues septic permits.4
  1. Resolve water and access. Idaho requires an IDWR drilling permit before a well is drilled.13 Work on a driveway or other access within a county road right-of-way requires the county access permit; a state-highway connection requires an ITD encroachment permit.2829
  1. Submit the building application, complete plans, plot plan and septic permit required by the county process.14
  1. Obtain electrical, plumbing and HVAC permits through the Idaho Division of Occupational and Professional Licenses.14
  1. Receive the building permit before starting work, then request each inspection 24 hours ahead, from footings through the final.518
  1. Keep the septic installation uncovered until the required health-district inspection is complete.8

What should you check before buying land in Lemhi County?

Start with buildability, not the listing description. Confirm the zoning district, overlays, legal access, applicable setbacks and whether the lot can support the intended use. Lemhi County regulates subdivisions, and each subdivision lot must accommodate a permitted use.30

Make septic feasibility an early contingency because only about 4.4% of county soils rate without severe limitations for a conventional drain field.21 The county is also steep overall, with about 28.4% of its land at a slope of 15% or less, so a parcel-specific house site, driveway and drain-field layout matter.31

Check flood status before designing because development in a Special Flood Hazard Area requires a floodplain development permit before work begins.32 Such projects also need a final as-built elevation certificate before the county issues a Certificate of Compliance or Occupancy.33 Confirm whether access meets the county-road or state-highway permit path.2829 Finally, budget around the countywide effective property-tax rate of about 0.4%, while verifying the actual parcel assessment and exemptions with the county.34

Watch-outs

  • Do not begin construction before the building permit is issued; Lemhi County says work and inspections cannot start earlier.5
  • In the Salmon Area of City Impact, both county and city development codes apply, and the more restrictive provision controls a conflict.6
  • A septic installation must remain uncovered until Eastern Idaho Public Health completes its required inspection.8
  • A driveway or other access within the county road right-of-way requires a Lemhi County access permit before the work begins.28
  • Private-land RV occupancy during construction, the building permit fee schedule and a countywide minimum dwelling size remain unconfirmed; ask the Building Department before committing to a plan.9
  • Idaho's owner-builder rule exempts owners who do their own work and do not intend to sell within 12 months from contractor registration only; it does not exempt the work from building, electrical, plumbing or inspection permits.35

Sources

  1. Lemhi County FAQs, quoted and re-checked
  2. Building, quoted and re-checked
  3. Lemhi County Development Code, quoted and re-checked
  4. Septic, quoted and re-checked
  5. Building Department FAQs, quoted and re-checked
  6. Lemhi County Development Code, quoted and re-checked
  7. Septic | Eastern Idaho Public Health, quoted and re-checked
  8. Septic Permit Application Packet, quoted and re-checked
  9. Lemhi County and City Building Department (lemhicountyidaho.org)
  10. Lemhi County Development Code, quoted and re-checked
  11. Idaho Division of Building Safety - Homeowners (2026 county census)
  12. Lemhi County Development Code, quoted and re-checked
  13. Wells Overview (Idaho statewide rule), quoted and re-checked
  14. Lemhi County Building Department Frequently Asked Questions, quoted and re-checked
  15. Idaho Adopted Codes, quoted and re-checked
  16. Agricultural Building Permit Exemption, quoted and re-checked
  17. Lemhi County Building Permit Application, quoted and re-checked
  18. Lemhi County Building Permit Application, quoted and re-checked
  19. Lemhi County Development Code, quoted and re-checked
  20. Eastern Idaho Public Health — Lemhi County Office (eiph.id.gov)
  21. Share of soils USDA rates "not limited" for a conventional septic drain field (SSURGO). A strict rating: the median county is about 6% and a tenth of counties are 0%, so a low figure means most lots need a site evaluation or an engineered system, not that septic is impossible. Cite it only with that caveat: Bolthole Index county data
  22. IDAPA 58.01.03 Individual/Subsurface Sewage Disposal Rules (Idaho statewide rule), quoted and re-checked
  23. Tiny Houses, Manufactured Homes, Modular Buildings & Recreational Vehicles, quoted and re-checked
  24. Lemhi County Development Code, quoted and re-checked
  25. Tiny Houses, Manufactured Homes, Modular Buildings & Recreational Vehicles, quoted and re-checked
  26. Lemhi County Development Code, quoted and re-checked
  27. Building Archives - Division of Occupational and Professional Licenses (Idaho statewide rule), quoted and re-checked
  28. Lemhi County Right-of-Way Access Permit, quoted and re-checked
  29. Types of Right-of-Way Encroachment Permits (Idaho statewide rule), quoted and re-checked
  30. Lemhi County Development Code, quoted and re-checked
  31. Share of land at 15% slope or less: Bolthole Index county data
  32. Lemhi County Development Code, Ordinance 2023-1, quoted and re-checked
  33. Lemhi County Development Code, quoted and re-checked
  34. Effective property tax rate: Bolthole Index county data
  35. Frequently Asked Questions (FAQ) - Division of Occupational and Professional Licenses (Idaho statewide rule), quoted and re-checked

Written October 9, 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.

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Compared with neighboring counties

Like all 6 of its neighbors, Lemhi County has countywide zoning.

RuleLemhi CountyCuster CountyValley CountyIdaho CountyClark CountyButte CountyCamas County
Building permitRequiredLimitedRequiredNot requiredLimitedRequiredRequired
County zoningYesYesYesYesYesYesYes
Septic permitsEastern Idaho Public HealthEastern Idaho Public HealthCentral District HealthPublic HealthEastern Idaho Public HealthSIPHSouth Central Public Health District

County locator

Lemhi County in Idaho

64
County map
Lemhi County highlighted among the Idaho counties · colored by Index score

How Lemhi County scores

Seclusion94100% ev.
Self-Sufficiency40100% ev.
Admin Boringness42100% ev.
Durability39100% ev.
Property Autonomy90100% ev.
Carry Cost77100% ev.

Evidence strength: 100%. This reports direct-source completeness and fallback use; it is separate from the score and is not a confidence interval. How it works →

$396kTypical home
0.4%Property tax
$3,947Land / acre
20.8"Annual rain
9.7% of yrsSevere drought
0.3 / yr (+0.3)Mid-century 100°F days
21.2 daysMid-century dry spell
1.11" (+6.7%)Mid-century 1-day rain
1.2×Wildfire change factor
100%Forward climate coverage
$1,713Home insurance / yr
4.3% / yrInsurance growth
0.99%Nonrenewal rate
county median (2+ published ZIPs)Insurance basis
174People within 30 min
898Radius comparison (15 mi)
1.8People / sq mi
90.9%Federal land
28.4%Land at 15% slope or less
4.4%Soils rated "not limited" for septic (strict USDA rating)
123,654 acWorkable land screen
49.2%Wooded land
23.3 tonsBiomass / forest ac
39.7°FAvg temp

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Cities and towns in Lemhi County

Inside a city or town, that city usually issues building permits and sets zoning; the county’s rules above cover unincorporated land. Septic, wells and floodplain rules usually stay with the county or state everywhere.

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Answers from the rulebook for Lemhi County

What the ordinances and state agencies actually say — one answer per question, each quoted from the official source and independently re-checked.

Lemhi County rules

  • Building permitRequired

    Building construction in Lemhi County.

    • A building permit application, complete building plans, and a plot plan are required.
    • A septic permit is required if building in the County.
    • No work may commence before permit issuance.
    • Applicable construction drawings and currently adopted codes are reviewed; payment is required before issuance.
    “No work may commence, nor will any inspection be performed, prior to a building permit being issued so please plan accordingly.”
  • Building code adoptedAdopted

    Building-code enforcement by the Lemhi County and City Building Department.

    • The page does not identify a specific code edition.
    “Other functions of this department include the enforcement of adopted building code regulations, emergency 911 addressing, and providing assistance to other County and City Departments.”
  • InspectionsRequired

    Construction subject to the Lemhi County and City Building Department inspection record.

    • All inspection requests must be made 24 hours in advance.
    • Work may not be covered or proceed beyond the inspection point until inspected and approved.
    • Required stages include footings, stemwalls, concrete slab, framing, insulation, interior wall finishing, and final inspection.
    • Re-inspections cost $47 per inspection; inspections exceeding one hour cost $47 per hour.

    inspection notice: 24 hours · re-inspection fee: 47 USD per inspection · inspection exceeding one hour: 47 USD per hour

    “REMEMBER: NO WORK IS TO BE COVERED OR GO BEYOND THE POINT OF INSPECTION UNTIL IT IS INSPECTED.”
  • Certificate of occupancyLimited

    Floodplain development requiring a Certificate of Compliance/Occupancy.

    • A final as-built finished-construction elevation certificate is required after construction and before issuance.
    • Deficiencies must be corrected before issuance.
    • Failure to submit the certification or correct deficiencies causes withholding of the certificate.
    “A final as-built Finished Construction Elevation Certificate (FEMA Form 86-0-33) is required after construction is completed and prior to Certificate of Compliance/Occupancy issuance.”
    One more reviewed finding on this topic
    • Limited — Development in a special flood hazard area requiring a Certificate of Compliance/Occupancy.
      “A final as-built Finished Construction Elevation Certificate (FEMA Form 86-0-33) is required after construction is completed and prior to Certificate of Compliance/Occupancy issuance.”
  • County-wide zoningPresent (with conditions)

    County zoning under the Lemhi County Development Code.

    • The ordinance is enacted under Chapter 65, Title 67, Idaho Code.
    • Specific uses may require special-use approval.
    “The “Official Zoning Map of Lemhi County” is adopted, by reference, as part of this ordinance.”
    2 more reviewed findings on this topic
    • Present (with conditions) — Land-use and zoning regulation under the Lemhi County Development Code.
      “This chapter creates zoning districts and overlay zoning districts based on the planning areas established in the comprehensive plan and adopts an official map of those districts.”
    • Present — County land-use zoning and overlay districts administered under the Lemhi County Development Code.
      “This chapter creates zoning districts and overlay zoning districts based on the planning areas established in the comprehensive plan and adopts an official map of those districts.”
  • Local zoningVaries (with conditions)

    Aggregate county result for county-administered zoning and the Salmon Area of City Impact.

    • The conclusion aggregates county zoning with the documented Salmon municipal/city-impact overlay; the county does not administer every municipal ordinance.
    • Within the Salmon Area of City Impact both codes apply and the more restrictive code controls.
    “Within the area of City impact both the Salmon Development Code and the Lemhi County Development Code shall apply. If a conflict occurs, the more restrictive code applies.”
  • Zoning districtsPublished

    Lemhi County zoning districts and overlay districts established by the Development Code.

    • The code adopts an official zoning map.
    • Additional performance standards may apply by district.
    “The “Official Zoning Map of Lemhi County” is adopted, by reference, as part of this ordinance. A dated copy of that map shall be maintained for public inspection at the office of the administrator.”
    One more reviewed finding on this topic
    • Published (with conditions) — County zoning districts and official zoning map.
      “The “Official Zoning Map of Lemhi County” is adopted, by reference, as part of this ordinance. A dated copy of that map shall be maintained for public inspection at the office of the administrator.”
  • Minimum lot sizeSpecified

    New development and lot creation under Lemhi County’s development code.

    • Minimum lot size varies by zoning district, geography, central water/sewer availability, and groundwater vulnerability areas.
    • All newly created lots must have at least 110 feet of frontage.
    • The table includes basic lots, central-water/sewer areas, groundwater-vulnerability areas, North Fork/Gibbonsville, and other named planning areas.

    minimum lot frontage: >= 110 feet · basic lot minimum: >= 1 acre (Central water or sewer areas: 1/2 acre; central water and sewer: 1/4 acre) · groundwater vulnerability area minimum: >= 2.5 acres (With central sewer: 1.5 acres; with central water and sewer: 1 acre)

    “There is a minimum lot size for any small-scale development. The minimum lot size may vary by zoning district or with the characteristics of the site, see table 6.5.”
    One more reviewed finding on this topic
    • District specific (with conditions) — New land divisions and development lots in Lemhi County zoning districts.
      “The minimum lot size may vary by zoning district or with the characteristics of the site, see table 6.5.”
  • SetbacksSpecified

    Building placement under the county building-permit application.

    • The application states the distances are examples and applicants should verify setbacks with the office before site preparation.
    • Different rules apply to existing lots in Elk Bend and Gilmore and to stream corridors and irrigation ditches.

    arterial-road setback: 25 feet · front-yard setback: 25 feet · corner-lot side-yard setback: 15 feet · rear setback: 10 feet for first 10 feet of wall height; 1:1 for greater heights · side setback: 10 feet for first 10 feet of wall height; 1:1 for greater heights

    “Setbacks For All Areas Setback From: Setbacks Distance (In Feet): Property line, arterial roads (measured from the edge of the road right of way) 25 feet Property line, front yard (measured from the edge of road right of way) 25 feet”
    One more reviewed finding on this topic
    • District specific (with conditions) — Building placement and setbacks in Lemhi County zoning districts and special areas.
      “Setbacks for Existing Lots in Elk Bend & Gilmore”
  • Manufactured homesAllowed (with conditions)

    Manufactured or mobile homes used as permanent single-family dwellings.

    • The home must comply with the National Manufactured Home Construction and Safety Standards Act or Building Code.
    • Hitches, wheels, chassis, and running gear must be removed and the home attached to a permanent foundation.
    • The home must be permanently connected to central or on-site utilities.
    “Includes both conventional dwellings and manufactured homes and mobile homes (rehabilitated under state requirements) that:”
  • Who permits septicLocal

    On-site and subsurface sewage disposal regulation for Lemhi County through Eastern Idaho Public Health.

    • EIPH serves Lemhi and seven other counties.
    • Public health districts are governmental entities authorized under Idaho Code Title 39, Chapter 4.
    “Eastern Idaho Public Health (EIPH) was created by the Idaho legislature in 1970 to provide services for Bonneville, Clark, Custer, Fremont, Jefferson, Lemhi, Madison, and Teton Counties.”
    One more reviewed finding on this topic
    • Local — Septic regulation and permitting for Lemhi County through Eastern Idaho Public Health.
      “Review applications for disposing of waste water, Perform onsite evaluations, Issue waste water permits, Conduct inspections, Provide technical assistance and education to the public and those that install septic systems.”
  • Septic permitRequired

    Installation of septic systems serving property in Lemhi County.

    • The county FAQ states that a septic permit is required if building in the county; EIPH provides the septic permit application and rules.
    “A septic permit is required if building in the County.”
    One more reviewed finding on this topic
    • Required — Construction, modification, repair, or expansion of individual or subsurface sewage disposal systems in Lemhi County.
      “It shall be unlawful for any person to cause or to perform the modifications, repair or construction of any individual or subsurface sewage disposal system within the State of Idaho unless there is a valid installation permit authorizing that activity.”
  • Septic inspectionRequired

    Septic systems installed under an EIPH permit in Lemhi County.

    • Inspection by an Environmental Health Specialist is required before covering.
    • Systems covered before inspection must be uncovered.
    • The owner or installer must call for final inspection.
    • EIPH requires 48 hours' notice to schedule an inspection.

    inspection notice: 48 hours

    “Final Inspection Mandatory: It is necessary to have the system inspected by an Environmental Health Specialist prior to covering in order to determine if the system was installed in accordance with the issued permit.”
  • Off-grid sanitationLimited

    Portable or non-discharging sanitation and individual subsurface sewage systems serving property in Lemhi County.

    • Portable non-discharging systems may be used on a temporary basis.
    • Other individual or subsurface sewage systems require a valid installation permit.
    • Repairs may be made for broken or clogged solid piping or electrical/mechanical malfunctions, but may not expand the system unless authorized.
    “Portable non-discharging systems may be used on a temporary basis”
  • Mandatory utility hookupConditional

    Subdivision and manufactured-home/recreational-vehicle-park development.

    • Subdivisions generally require electric power and telephone connections for each lot.
    • Remote or primitive subdivisions may be exempt if future utility easements are provided.
    • Manufactured-home/RV parks must be readily accessible to public or private water, sewerage, and electricity services.
    “electric power and telephone connections for each lot, including any extension of lines or cables required to serve the subdivision, in compliance with the standards established by the utility involved;”
  • Agricultural exemptionConditional

    Agricultural buildings meeting Lemhi County Ordinance 2016-1 requirements.

    • The building must be used solely for listed agricultural purposes.
    • The property must be determined by the Lemhi County Assessor to be actively devoted to agriculture.
    • The building may not be used for human habitation, public use, a shop or machinery repair building, or personal vehicle storage.
    • The owner must obtain a site permit.
    • Setbacks and engineering safety requirements still apply.
    • Construction may not begin until site evaluation and written approval.
    “The building is used solely for one or more of the purposes listed in subsection (1)(a) above; and”
  • Subdividing landRegulated (with conditions)

    Creation of new parcels, subdivisions, and certain lot-line adjustments in Lemhi County.

    • Subdivision permits are designed to ensure creation of new parcels and proposed uses do not violate the development code.
    • A lot-line adjustment within a platted subdivision that changes external boundaries is treated as an amended subdivision and follows the subdivision or plat-vacation process under Idaho Code 50-13.
    “The developer may file a final plat with the administrator at any time after the subdivision permit is approved and the decision of record has been signed.”
  • Driveway accessRequired

    Work involving a driveway or other access within the Lemhi County road right-of-way.

    • The access permit requires an aerial photograph or property sketch and information on approach angle, sight distance, proposed access width, distance to the nearest existing access, distance to the nearest intersection, and culvert details.
    • The recommended distance to the nearest existing access is 150 feet and may not be less than 50 feet.
    • The grade may not be greater than 3% at the edge of the road right-of-way.
    • A 50-foot stopping zone is required.
    • Drainage must not drain onto the County right-of-way.
    • At least 24 hours advance notice is required before work that would restrict traffic.
    • Failure to obtain and properly complete the permit before working within the right-of-way may result in suspension of work, possible fines, and suspension from future right-of-way work.
    • The permit becomes void 30 days after issuance.
    • Fees are based on actual County costs for plan review and construction observation.

    recommended distance to nearest existing access: 150 feet (Not less than 50 feet.) · minimum distance to nearest existing access: >= 50 feet · maximum grade at road right-of-way edge: <= 3 percent · stopping zone: 50 feet · permit validity: 30 days

    “Failure to Obtain a Permit - Should the Contractor fail to obtain and properly fill out a permit prior to working within the right-of-way, Lemhi County shall suspend the work until such time the permit is approved and possible fines are paid.”
    One more reviewed finding on this topic
    • Required — New accesses or driveways to county-owned roads in Lemhi County.
      “New accesses/driveways to county owned roads will require an “Lemhi County Right of Way Access Permit” from the Lemhi County Road and Bridge Department (LCRB).”
  • Building in a floodplainRequired

    Development within Lemhi County Special Flood Hazard Areas.

    • Applications for a floodplain development permit must be made before development activities in Special Flood Hazard Areas; additional elevation, floodproofing, and certification requirements may apply.
    “A Floodplain Development Permit shall be required in conformance with the provisions of this ordinance prior to the commencement of any development activities within Special Flood Hazard Areas determined in accordance with the provisions of C.4.2.”
  • Permit processPublished (with conditions)

    The Lemhi County Building Department's published process for obtaining a building permit for construction in the county.

    • Submit a building permit application.
    • Submit a complete set of building plans.
    • Submit a plot plan showing where the building will be placed.
    • A septic permit is required if building in the County.
    • The plot plan should note property-line setbacks; setback requirements are in the applicable Building Permit Application packet.
    • Electrical, HVAC, and plumbing permits are obtained through the Idaho Division of Occupational and Professional Licenses.
    “To obtain a building permit, you will need: A building permit application. A complete set of building plans. A plot plan showing where on your property you are putting your building. A septic permit is required if building in the County.”
    2 more reviewed findings on this topic
    • Partial — Building permit applications in Lemhi County.
      “To obtain a building permit, you will need: A building permit application. A complete set of building plans. A plot plan showing where on your property you are putting your building.”
    • Published (with conditions) — County building permit application process for new construction.
      “Please fill out the enclosed application COMPLETELY. Incomplete applications WILL NOT be accepted.”

Idaho rules that apply here

  • Owner-builder exemptionConditional

    Homeowners personally performing plumbing work on their own residential premises in Idaho.

    • The homeowner must own the residential property and personally perform the permitted work.
    • The homeowner permit is valid only for a primary or secondary residence and associated outbuildings.
    • Associated outbuildings must not be used for commercial purposes or rented by a tenant.
    • The homeowner must accept responsibility for all work performed.
    • All work must be inspected by the Division of Occupational and Professional Licensing.
    • A plumbing permit must be obtained by application to the Division.
    • The application must be submitted with payment.
    • The application form states that an additional $65 fee may be assessed if the location is not clearly provided by directions or an attached map.
    • The application was revised 8/17/2022; this revision date is not treated as an effective date.

    unclear-location fee: 65 USD (May be assessed if the location is not clearly given by directions or an attached map.)

    “I certify that I am the owner of the residential property and will personally perform the work covered by this permit.”
    4 more reviewed findings on this topic
    • Available — An owner performing their own construction work on the owner's own land in Idaho.
      “A: Any person who engages in a construction job with a dollar amount exceeding $2000.00 (materials & labor) and is not otherwise exempt (The exemptions are listed below); [...] Owners: Owners who do their own work on their own land and do not intend to sell the property within 12 months are exempt from registration.”
    • Conditional — An Idaho homeowner undertaking construction or trade work for which a state-administered permit process applies.
      “Public (Homeowners Only) [...] *Public: “Homeowner” is pre-selected. [...] Once payment is processed, you may choose “Request Inspection” and/or “Print Permit””
    • Conditional — Owners performing construction work on their own land in Idaho under the state contractor-registration system.
      “Owners who do their own work on their own land and do not intend to sell the property within 12 months are exempt from registration.”
    • Conditional — Homeowners personally performing electrical work on a primary or secondary residence and related outbuildings in Idaho.
      “Homeowners may purchase a permit only when they themselves are doing electrical work on their primary or secondary residence and/or related outbuildings.”
  • Living in an RVTemporary only (with conditions)

    Recreational vehicle use and occupancy in Lemhi County.

    • The source states that temporary recreational lodging is the only legal use.
    • Placement and occupancy are regulated by local planning and zoning ordinances.
    • RVs must comply with ANSI A119.2 or A119.5 standards.

    maximum width: 8.5 feet

    “Their width is limited to 8½ feet and temporary recreational lodging is the only legal use.”
  • Camping on your landLimited

    Camping or parking a vehicle or trailer on Idaho Fish and Game Wildlife Management Areas and access sites separate from a WMA.

    • The restriction applies in areas posted against camping or parking.
    • Leaving an unattended camp, vehicle, or trailer for more than 48 hours is prohibited without authorization.
    • Camping or parking for more than 10 days during any 30-day period on one WMA or one separate access site is prohibited without authorization.
    • The rule permits authorization by the Commission, Director, Regional Supervisor, or designee.

    unattended duration: > 48 hours (Unless specifically authorized by the Commission, Director, Regional Supervisor, or designee.) · camping or parking duration: > 10 days during any 30-day period per WMA or separate access site (Unless specifically authorized by the Commission, Director, Regional Supervisor, or designee.)

    “camp or park a vehicle or trailer for more than ten (10) days during any thirty (30) day period”
  • Tiny homesLimited

    Tiny houses used as dwellings in Lemhi County.

    • Every dwelling, including a tiny house, must comply with one of the listed classifications.
    • A tiny house classified as an RV may face planning and zoning approval challenges.
    • If wider than 8½ feet, it cannot be an RV but may be a modular building.
    • Site-built and modular buildings must comply with building-code minimum area requirements.

    RV maximum width: 8.5 feet (Wider structures may be modular buildings) · approximate minimum building-code floor area: 150 square feet (The source describes this as about 150 square feet)

    “If you are planning to build or purchase a dwelling of any kind, including a “tiny house”, it must comply with the requirements of one of the classifications listed above.”
  • Accessory dwellingsLimited

    Accessory dwelling units for Idaho DEQ wastewater-flow and septic-system sizing purposes; this claim does not establish statewide zoning permission.

    • An ADU is sized as a single-family dwelling for the cited wastewater-flow guidance.
    • An ADU may combine flows with another structure into one system.
    • Any common septic tank must be large enough to hold the required capacity from both structures.
    • Local land-use, building, and septic authorities may impose additional requirements.

    wastewater flow basis: single-family dwelling

    “Size as a single family dwelling. Can combine with another structure's flows into one system”
  • Well permitRequired

    Construction or drilling of wells in Idaho, including domestic wells.

    • Before drilling, the well owner or driller must obtain a drilling permit from IDWR.
    • All wells must be constructed by a well driller with a valid IDWR license.
    • The separate water-right permit exemption for domestic purposes does not eliminate the drilling-permit requirement.
    • For new diversions in qualifying subdivisions filed on or after July 1, 2025, a water-right permit is required in a moratorium area, critical groundwater area, or groundwater management area, except for in-home uses and watering livestock.
    • Well construction rules apply to wells and other artificial openings more than 18 vertical feet below land surface.

    well depth threshold: > 18 vertical feet below land surface (The cited well-construction rules describe covered wells and artificial openings.) · subdivision application date: >= 2025-07-01 (Applies to qualifying new diversions described in Idaho Code § 42-227(4).)

    “Prior to drilling a well, the well owner or well driller must first obtain a drilling permit from IDWR.”
  • Campground & park staysLimited

    Temporary camping in Idaho State Parks administered by the Idaho Department of Parks and Recreation.

    • Camping is permitted only in designated areas.
    • Stays are limited to 14 nights in a 30-day period; the same page's FAQ separately states a 15-day limit, creating an unresolved internal discrepancy.
    • Individual-site occupancy is limited to one family unit or no more than 8 persons unless otherwise specified; companion-site and site-design restrictions apply.
    • Camping is not permitted on beaches, parking lots, or day-use facilities.
    • Check-in is at 2 p.m. for campsites and checkout is at 1 p.m.; late checkouts may incur additional fees unless prior arrangements have been made.

    state-park stay limit: 14 nights in 30 days (FAQ on the same page states 15 days in any 30-day period) · individual-site people limit: <= 8 people (one family unit or site-specific limits may apply)

    “Camping is permitted only in designated areas. [...] Stays are limited to 14 nights in a 30-day period.”
  • county zoning authorityGeneral

    Idaho counties adopting zoning for unincorporated areas through their boards of county commissioners.

    • A board of county commissioners is a governing board and may exercise the powers authorized by the Local Land Use Planning Act.
    • The county board's powers under the chapter apply to the unincorporated area of the county.
    • Zoning must be adopted, amended, or repealed by ordinance using the notice and hearing procedures in Idaho Code § 67-6509.
    • Zoning districts must conform to the adopted comprehensive plan.
    • Within zoning districts, standards may regulate or restrict building height, number of stories, size, construction, reconstruction, alteration, repair or use of buildings and structures; lot occupancy; courts, yards and open spaces; population density; and building and structure location and use.
    • Standards must be uniform for each class or kind of building throughout each district, but may differ between districts.
    • Overlay zoning districts require clear and objective standards and must not constitute a regulatory taking under Idaho or federal law.
    “The powers of the board of county commissioners conferred by this chapter shall apply to the unincorporated area of the county.”
  • county building authorityGeneral

    Idaho counties' authority to adopt and enforce building codes and require permits for residential construction in unincorporated areas when the county operates a building-code enforcement program.

    • The statute defines local government as any city or county of Idaho.
    • A local government that had not previously implemented a code-enforcement program may elect to implement one by ordinance evidencing its intent to do so.
    • Construction in a local-government jurisdiction enforcing building codes requires a permit under the applicable local ordinance.
    • A local government issuing permits and performing enforcement must adopt the specified state-adopted codes and may amend them only within the limits stated in Idaho Code § 39-4116(4).
    • Local amendments must generally provide at least an equivalent level of protection; accessibility amendments are restricted, and additional residential-code amendments require the statutory good-cause, necessity, ordinance, public-hearing, publication, and notice procedures.
    • Single-family homes and multiple-family dwellings up to two units are exempt from automatic fire-sprinkler requirements in the enumerated codes.
    • Agricultural buildings must be exempted; a county may issue farm-building permits only for road setbacks and utility easements, at no more than actual issuance cost.
    • Permits are governed by the laws in effect when the application is received.
    • The state division retains jurisdiction for in-plant inspections and installation standards for manufactured or mobile homes and for in-plant inspections and enforcement of modular-building and commercial-coach construction standards.
    “"Local government" means any city or county of this state.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission — ask the county directly.

  • Minimum dwelling size — County land-use minimum dwelling size in Lemhi County.
  • Lot coverage — Lot coverage limits in Lemhi County zoning districts.
  • Building height — Building-height limits in Lemhi County zoning districts.
  • Short-term rentals — Short-term rental use in Lemhi County.
  • Permit fees — County building-permit fees.

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.

Living off-grid in Lemhi County, Idaho

Is Lemhi County a good place to live off-grid or homestead?

Lemhi County scores 64/100 on the Bolthole Index, a strong county profile. Its strengths: deep seclusion — about 174 people within a 30-minute drive and a stronger property-autonomy legal backdrop. Watch-outs: elevated current hazard exposure and thin water margin (20.8″/yr rainfall).

Do you need a building permit in Lemhi County, Idaho?

Lemhi County generally requires a residential building permit, and it enforces county zoning. Onsite septic is permitted by Eastern Idaho Public Health. Owner-builders may act as their own contractor to build their home. These answers are quoted from official sources and independently re-checked. Rules change and cities within the county differ — always confirm with the county before you buy or build.

Can you live in an RV or tiny home on your land in Lemhi County?

Living in an RV on your own land in Lemhi County is allowed on a temporary basis only: Statewide rule. Recreational vehicle use and occupancy in Lemhi County. The source states that temporary recreational lodging is the only legal use. Placement and occupancy are regulated by local planning and zoning ordinances. A tiny home is limited to specific cases. Confirm with the county before relying on it.

How much does land cost in Lemhi County, Idaho?

Land in Lemhi County runs about $3,947 per acre, based on the latest county data.

What is the water situation in Lemhi County?

Lemhi County gets about 20.8" of rain a year, with severe drought in roughly 9.7% of years.

How remote is Lemhi County?

A typical private-land location has about 898 people within 15 miles and 289,398 within 100 miles. These radius catchments are the published fallback where road routing is unavailable.

How Lemhi compares in Idaho

Compare side-by-side →See all 44 Idaho counties ranked →