Bolthole Index

Elmore County, Idaho

Zoning, building permits and septic rules in Mountain Home, Idaho

Inside Mountain Home, Idaho city limits, the city's own Building Services office issues building permits1 and the city administers its own zoning ordinance2. Septic permits in Elmore County come through Central District Health3, and whether a city lot must connect to city sewer instead is unconfirmed, so ask the city before you buy. Land outside city limits falls under Elmore County's rules instead4.

At a glance

Building permit
Required inside city limits, issued by the city1
Zoning
City zoning ordinance (Title 9) applies inside city limits2
Building code
International codes adopted by the city, plus state-adopted codes5
Septic
Central District Health oversees septic permits in Elmore County; city-lot rules unconfirmed3
Manufactured homes
Allowed on individual lots where the use chart permits; city permit required to install6
Minimum lot size
9,000 sq ft in R-2; 6,500 sq ft in R-3; 5,000 sq ft in R-4789
Wells
State drilling permit from IDWR before drilling10

Who to call

Building permits

City of Mountain Home Building Services

Building permits, plan review, inspections and certificates of occupancy inside Mountain Home city limits

208-580-2091

160 South 3rd East St. Mountain Home, ID 83647

Planning & zoning

City of Mountain Home Planning & Zoning Division

Zoning and subdivision ordinances and the comprehensive plan inside Mountain Home city limits

Septic permits

Central District Health, Environmental Health Division

Septic permits, site evaluations and land-development review for Elmore County

(208) 375-5211

Online permits →

Contact details are copied from each office’s official page and were checked against it on October 23, 2026.

Off-grid gear

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

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Do you need a building permit in Mountain Home, Idaho?

Yes. Inside Mountain Home city limits, work on a project that needs a building permit may not start until the permit is issued, and starting early is an infraction1. The same code requires a building permit for fences, walls and similar structures1 and for installing a mobile home on any lot in the city1. The city adopted International Code Council codes, including the International Residential Code, and also enforces codes the state adopts5. Agricultural buildings are exempt from those building codes but still must meet zoning placement rules11. Fees vary by project12. Whether an owner can build their own home inside the city is something we could not confirm; ask Building Services13.

Who issues building permits in Mountain Home, and how do you reach them?

The City of Mountain Home Building Services office issues building permits, reviews plans and inspects construction inside city limits13. Call 208-580-2091 and apply through the city's OpenGov portal13. The office is at 160 South 3rd East St. in Mountain Home13. Zoning questions go to the city's Planning & Zoning Division, which administers the zoning and subdivision ordinances14. Do not use the Elmore County Land Use and Building Department for an address inside city limits; its building permits cover unincorporated Elmore County15.

Does Mountain Home have zoning, and what does it mean for homes and lots?

Yes. Mountain Home administers its own zoning ordinance, Title 9 of the city code, and divides the incorporated city into zoning districts shown on an official zoning map2. Dimensional rules differ by district. The minimum lot is 9,000 square feet in R-27, 6,500 square feet in R-38 and 5,000 square feet in R-49. Minimum dwelling sizes appear to run 1,500 square feet on the ground floor in R-116, 1,300 in R-217 and 1,100 in R-318; confirm against the city's official chart. A detached accessory building may not cover more than 15% of the lot in R-3 and R-419. Residential driveways must be paved with asphalt or concrete to city standards20.

How do septic permits work in Mountain Home?

Septic permits in Elmore County are handled by Central District Health's Environmental Health Division321. Idaho requires a permit to install, modify or repair an individual or subsurface sewage system22. The city code we reviewed has no septic provision, and we could not confirm whether a lot inside city limits must connect to city sewer instead. Before buying a lot you plan to septic, ask the City of Mountain Home Wastewater Division whether sewer is available, then ask Central District Health at (208) 375-521121. Domestic wells need a drilling permit from the Idaho Department of Water Resources before drilling begins10.

Can you live in an RV or tiny home in Mountain Home?

We could not confirm the city's rule on living in an RV inside Mountain Home city limits. Call Building Services at 208-580-2091 before you park an RV on a lot13. Manufactured homes are treated differently: Class A manufactured homes on individual lots are allowed where the land use chart permits them, each on its own lot following R-4 lot specifications6. A permit from the city building official is required before a mobile home is installed1. Manufactured home parks are a conditional use6. Outside city limits, Elmore County allows permanent living in an RV when its conditions are met23.

Building a home in Mountain Home: the steps, in order

  1. Confirm the lot is inside city limits and find its zoning district with the Planning & Zoning Division14.
  2. Check lot size, setbacks and minimum dwelling size for that district24.
  3. Ask the city whether sewer is available; if not, contact Central District Health about a septic permit21.
  4. If you need a well, get the state drilling permit first10.
  5. Apply for the building permit through Building Services before any work starts113.
  6. Schedule inspections by phone with Building Services13.

What stays with Elmore County, and what to check before you buy

Septic permits and health review stay with Central District Health, not the city3. Land outside city limits follows Elmore County's zoning, which applies to unincorporated Elmore County4; see the Elmore County page for those rules. Check the lot's zoning district, sewer or septic route, well permit, and driveway access. A driveway that connects to a state highway needs a state permit25. Elmore County's effective property tax rate is 0.6%26.

Watch-outs

  • We could not confirm the city's rules on RV occupancy, owner-builder construction, or certificates of occupancy inside Mountain Home; call Building Services at 208-580-209113.
  • The city's zoning chart is hard to read in places, so confirm lot size, floor area and setbacks with the Planning & Zoning Division before buying24.
  • Elmore County's building and zoning rules do not apply inside city limits; they cover unincorporated land4.

Sources

  1. Mountain Home City Code 5-1-1 adoption of building codes through 5-1-10 (Mountain Home), quoted and re-checked
  2. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  3. Septic, Subdivisions & Water, quoted and re-checked
  4. Amended Zoning and Development Ordinance, quoted and re-checked
  5. Mountain Home City Code 5-1-1 adoption of building codes through 5-1-10 (Mountain Home), quoted and re-checked
  6. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  7. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  8. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  9. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  10. Wells Overview (Idaho statewide rule), quoted and re-checked
  11. Mountain Home City Code 5-1-1 adoption of building codes through 5-1-10 (Mountain Home), quoted and re-checked
  12. Mountain Home City Code 5-1-1 adoption of building codes through 5-1-10 (Mountain Home), quoted and re-checked
  13. City of Mountain Home Building Services (mountain-home.us)
  14. City of Mountain Home Planning & Zoning Division (mountain-home.us)
  15. Building Permit Requirements: – Elmore County, Idaho, quoted and re-checked
  16. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  17. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  18. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  19. Mountain Home City Code 9-7-7 bulk and coverage controls, 9-7-8 schedule, 9-7-9 residential bulk controls (Mountain Home), quoted and re-checked
  20. Mountain Home City Code 9-7-7 bulk and coverage controls, 9-7-8 schedule, 9-7-9 residential bulk controls (Mountain Home), quoted and re-checked
  21. Central District Health, Environmental Health Division (cdh.idaho.gov)
  22. IDAPA 58.01.03 – Individual/Subsurface Sewage Disposal Rules and Rules for Cleaning of Septic Tanks (Idaho statewide rule), quoted and re-checked
  23. Living in Recreational Vehicles, quoted and re-checked
  24. Mountain Home City Code 9-7-4 land use chart and 9-7-6 zoning districts (Mountain Home), quoted and re-checked
  25. Types of Right-of-Way Encroachment Permits (Idaho statewide rule), quoted and re-checked
  26. Effective property tax rate: Bolthole Index county data

Written October 23, 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 Mountain Home

Mountain Home’s own rules

  • Building permitRequired

    Work needing a building permit inside Mountain Home city limits, including new construction, fences over 30 inches, and mobile home installations

    • Work on a project needing a building permit may not start before the permit is obtained; violation is an infraction under section 1-4-1 (5-1-1 d.).
    • A permit is required to install or locate a mobile home on any property within city limits, except mobile homes displayed for sale (5-1-8).
    • A building permit is required for construction of fences, walls, latticework screens and similar structures (9-7-7 c.2).
    “it shall be unlawful for anyone to start work on any project needing a building permit before obtaining one.”
  • Building code adoptedAdopted (with conditions)

    All buildings and structures inside Mountain Home city limits

    • Adopted codes are the International Code Council codes listed in 5-1-1 a.1 through a.9: 2012 International Building Code (with Idaho Building Code Board amendments, excluding the electrical, mechanical, fuel gas, plumbing and fire codes except as referenced), 2009 International Residential Code (excluding parts v through viii), 2009 International Energy Conservation Code, 2012 International Property Maintenance Code, 2012 International Existing Building Code, 1997 Uniform Code for the Abatement of Dangerous Buildings, 2012 International Fire Code, 2012 Mechanical Code and 2012 Fuel Gas Code.
    • The section states that as the international codes are revised and republished, the current editions become the city's building codes, effective January 1 following publication.
    • The city also administers and enforces codes adopted by the state under the Idaho building code advisory act of 1975.
    • Amendments: drinking fountains not required for occupant load of 30 or fewer; service sinks not required for certain business occupancies; carbon monoxide alarm and fireplace damper amendments.
    • Section 5-1-1 b. exempts agricultural buildings from the adopted building codes, but they remain subject to zoning placement rules.
    “the city hereby adopts the following documents and codes published by the international code council, effective january 1, 2014”
  • Local zoningPresent (with conditions)

    Land inside Mountain Home city limits (the incorporated area of the city), not unincorporated Elmore County

    • The city administers its own zoning ordinance, Title 9 Land Use and Development, chapter 7 Land Use Control.
    • Section 9-7-5 states the district regulations are minimum regulations that apply uniformly to each class or kind of structure or land.
    • Uses are governed by the land use chart in section 9-7-4 (permitted, conditional, permitted accessory).
    “9-7-6: zoning districts: the incorporated area of the city shall be divided into the following zoning districts whose boundaries are shown on the official city zoning map.”
  • Zoning districtsPublished (with conditions)

    Zoning districts of the incorporated city of Mountain Home

    • Districts are R-1, R-2, R-3, R-4, LO/R, C-1, C-2, C-3, C-4, I-1 and I-2 (9-7-6).
    • Boundaries are shown on the official city zoning map, which was not captured.
    “9-7-6: zoning districts: the incorporated area of the city shall be divided into the following zoning districts whose boundaries are shown on the official city zoning map.”
  • Minimum dwelling sizeSpecified

    Single-family dwellings in the R-2 low density residential zone inside Mountain Home city limits

    • Up to 10 percent of R-2 dwellings may be single-family attached unless developed as a planned unit development (9-7-6 b.3).
    • Same unlabeled-schedule caveat as R-1.

    minimum floor area (ground floor and two-story): 1,300 ground floor, 1,600 minimum/2 story

    “r-2 9,000 sf 2 7,200 - 10,800 sf 35% 65% 80' 25' 1 20' 15' 5' 12' 25' 30' 1,300 ground floor, 1,600 minimum/2 story”
    2 more reviewed findings on this topic
  • Minimum lot sizeSpecified

    Single-family and attached single-family lots in the R-2 low density residential zone inside Mountain Home city limits

    • For new subdivisions of 5 acres or less, the minimum lot size applies to all lots; for subdivisions larger than 5 acres a lot-size range of 7,200 to 10,800 sf applies with 20 percent of lots at each end (9-7-9 a.2 and a.3).
    • Each duplex unit minimum follows the low end of the range (9-7-9 a.5).

    minimum lot size: >= 9000 sq ft (subdivisions over 5 acres use a 7,200 to 10,800 sf range)

    “r-2 zone/residential zone (low density residential/9,000 square foot minimum lot)”
    2 more reviewed findings on this topic
  • SetbacksSpecified

    Residential lots in the R-1 zone inside Mountain Home city limits

    • Front setback to gateway streets and highways is 30 feet; to arterial or collector streets 25 feet; large or tall buildings may require 60 feet (9-7-9 b.1).
    • Lots with a front-loaded garage use column 6 of the schedule; side-yard setbacks must meet the minimum and combined requirements (9-7-9 c.1).
    • Odd-numbered lots have a 2-foot larger front setback than even-numbered lots (schedule note 10).
    • Detached accessory buildings must be in the rear or side yard only (9-7-7 b.3.b.4).
    • The schedule's column order is not labeled in the captured text; the R-1 numbers in the row cited here must be checked against the official chart before use for a specific rear or side yard figure.

    front setback to gateway streets and highways: >= 30 ft (arterial or collector streets 25 ft)

    “the minimum front setback to gateway streets and highways is thirty feet (30');”
    3 more reviewed findings on this topic
  • Lot coverageSpecified

    R-3 and R-4 zones inside Mountain Home city limits; the schedule shows no general lot coverage figure for these districts

    • Schedule note 13 caps detached accessory buildings at 15 percent of the lot.
    • The R-3 and R-4 rows show n/a in the lot coverage and yard area columns, with note 13 referenced.

    maximum detached accessory building share of lot: <= 15 percent

    “13. no detached accessory building shall occupy more than 15% of the lot.”
    2 more reviewed findings on this topic
  • Building heightSpecified

    Principal residential buildings in the R-1, R-2, R-3 and R-4 zones inside Mountain Home city limits

    • The maximum building height in the schedule for each of the four residential districts is read as the last height value before the floor-area column (30 feet in each row).
    • Schedule note 12: FAA regulations may reduce the building height allowance.

    maximum building height: <= 30 ft (FAA regulations may reduce the allowance (schedule note 12))

    “r-4 5,000 sf 2 5,000 - 7,000 sf n/a 13 n/a 13 50' 15' 1 20' (garage) 15' 15' 5' 12' 15' 30' n/a”
  • Manufactured homesAllowed (with conditions)

    Class A manufactured homes on individual lots inside Mountain Home city limits, in districts where the land use chart marks them as permitted

    • A manufactured home shall have its own lot in accordance with the R-4 lot specifications (land use chart note 6).
    • A permit from the city building official is required before a mobile home is installed or located on property inside city limits (5-1-8), except mobile homes displayed for sale.
    • Manufactured home parks are a conditional use in the chart ("manufactured home park p p p p c c") and are subject to chapter 15 MHP subdistrict zone.
    • The captured text of the land use chart shows six 'p 6' entries without column labels; the exact districts where individual-lot manufactured homes are permitted could not be mapped from the text.
    “manufactured homes (class a/individual lots) p 6 p 6 p 6 p 6 p 6 p 6 p 6”
  • Mandatory utility hookupWater and sewer (with conditions)

    Industrial zones I-1 and I-2 inside Mountain Home city limits only; not single-family homes

    • Applies to I-1 and I-2 zoned land; the I-2 text uses the same connection requirement.
    • The rule is a location requirement for industrial development and does not state a distance for homes.
    “any i-1 district shall be annexed into the city and must be in proximity to ensure connection to the municipal water and sewer systems of the city.”
  • Agricultural exemptionAvailable (with conditions)

    Agricultural buildings inside Mountain Home city limits, exempt only from the city building codes

    • Agricultural buildings remain subject to placement requirements established by zoning regulations.
    • This is an exemption from building codes only; it does not establish an agricultural use right under zoning.
    “agricultural buildings are exempt from the building codes adopted herein, but shall remain subject to placement requirements established by zoning regulations.”
  • Subdividing landRegulated (with conditions)

    New subdivisions of land inside Mountain Home city limits

    • Subdivisions are governed by Title 9 chapter 16 Subdivisions (table of contents), and minor division and lot line adjustments under 9-6-7 and 9-6-8 (not opened).
    • Lots in new subdivisions of 5 acres or less in R-2, R-3 and R-4 must meet the minimum lot size; larger subdivisions use the lot-size range (9-7-9 a.2 and a.3).
    “the minimum lot size (section 9-7-8, column 1 of this chapter) is required for all lots in new subdivisions of five (5) acres or less in the r-2, r-3 and r-4 zoning districts.”
  • Driveway accessRequired

    Access driveways serving residential lots inside Mountain Home city limits

    • Driveways must be improved with asphalt or concrete to meet city standards (9-7-7 b.3.b.1).
    • Vehicles must be parked in designated improved driveways (9-7-7 b.3.b.2).
    • Vision triangle at corner lots and driveways must not be obstructed (9-7-7 b.3.a).
    “1. access driveway improved with asphalt or concrete to meet city standards.”
  • Permit feesVariable (with conditions)

    Building permit and plan review fees inside Mountain Home city limits

    • Fees follow the city building permit fee table adopted as exhibit A to the ordinance; the table itself was not in the captured text.
    • Value of construction is the greater of the building valuation data table amount or the applicant's estimate.
    • Fixed fees are set by city council resolution; public entities may be exempted by council approval, with the applicant bearing added city costs.
    “c. fixed fees: certain building permit and plan review fixed fees to reflect, as close as possible, the actual hourly costs to the city are established by resolution of the city council.”

Still unanswered

We looked and could not find an official answer yet. Silence is not permission; ask Mountain Home or Elmore County directly.

  • Owner-builder exemption — Owner-builder construction of a residence inside Mountain Home city limits
  • Inspections — Inspections for construction inside Mountain Home city limits
  • Certificate of occupancy — Certificates of occupancy inside Mountain Home city limits
  • Living in an RV — Living in an RV on a lot inside Mountain Home city limits
  • Camping on your land — Temporary camping on private land inside Mountain Home city limits
9 more unanswered
  • Tiny homes
  • Accessory dwellings
  • Who permits septic
  • Septic permit
  • Septic inspection
  • Off-grid sanitation
  • Well permit
  • Building in a floodplain
  • 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 Mountain Home publishes no rule on the point, not that none exists. Elmore County’s page lists the county offices to call.

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