Boise County, Idaho requires a building permit for new construction, issued by the Planning & Zoning Department, and site plans must show Wildland-Urban Interface defensible space and setbacks1. The county also enforces zoning districts and setbacks2. Central District Health, not the county, issues septic permits and reviews the required site evaluation34.
At a glance
- Building permit
- Required, through Planning & Zoning; site plans must show defensible space and setbacks1
- Zoning (unincorporated county)
- Yes, a Unified Land Use Ordinance enforced by Planning & Zoning2
- Septic permit
- Required through Central District Health, with a site evaluation45
- Owner-builder rule
- Not confirmed; no county owner-builder statement was found6
- Building inspections
- Required; most residential construction is priced around six inspections7
- Septic soil suitability
- Only about 0.1% of county land is free of severe limits for a conventional drain field8
- Manufactured home
- Installation must be inspected and approved before occupancy9
- Property tax
- About 0.4% effective rate; $1,571/yr median bill1011
Who to call
Building permits
Boise County Planning & Zoning Department
Building permits, land-use permits and zoning administration under the Unified Land Use Ordinance for Boise County, with a separate Building Inspector/Code Enforcement line for scheduling inspections
413 Main Street, PO Box 1300, Idaho City, ID 83631
Septic permits
Central District Health - Idaho City Office
Central District Health's office inside Boise County; CDH's Environmental Health Division permits septic systems for the county
102 Centerville Rd, Idaho City, ID 83631
Contact details are copied from each office’s official page and were checked against it on September 29, 2026.
Do you need a building permit in Boise County, Idaho?
Yes. Boise County requires a building permit for new construction, and the site plan must show Wildland-Urban Interface defensible space and setbacks1. Idaho has adopted the 2018 International Building Code and the Idaho Residential Code (2020 Edition), based on parts of the 2018 International Residential Code with Idaho amendments12. A pre-application meeting with the Planning & Zoning Administrator is required before any land-use or development application13. Boise County requires building inspections; its fee schedule bases most residential work on six inspections at $150 each, although some projects need more or fewer7. Electrical, plumbing and HVAC work require separate trade permits14.
Who is the Boise County building department, and how do you reach them?
Boise County Planning & Zoning handles building permits, land-use permits and zoning administration13. Reach the office at 413 Main Street, PO Box 1300, Idaho City, ID 83631, phone 208-392-229313. The office is open Monday through Thursday, 8:00 am to 5:00 pm, and Friday 8:00 am to 1:00 pm; building-permit service is limited to 8:30 am through 4:00 pm13. For inspections, call 208-781-8565 and allow 48 hours excluding weekends13. Boise County publishes a $100 minimum building-permit fee and a $50 minimum plan-review fee; outside professional costs can also be charged, and review stops if a required supplemental payment remains unpaid1516.
Does Boise County have zoning?
Yes. Boise County administers a Unified Land Use Ordinance with zoning districts and setback standards enforced by the Planning & Zoning Department2. The county's own site currently lists this as an Amended Unified Land Ordinance 2024-02, so ask Planning & Zoning which edition applies to your parcel before relying on an older copy13. Boise County even publishes its own standards specifically for tiny homes and RVs among its zoning documents, worth pulling before you plan to live in either on your land13. Because zoning is active here, do not assume rural Idaho land is unrestricted; confirm your parcel's zoning district, setbacks, and any defensible-space requirements with Planning & Zoning before you design a build131.
How do septic permits work in Boise County?
Central District Health issues Boise County septic permits and reviews land-development applications for sanitary restrictions317. CDH's Idaho City office is at 102 Centerville Rd, Idaho City, ID 83631, phone 208-327-740018. Apply through CDH's permit portal and submit the required plot plan and fees1920. Test holes are required for every lot or parcel; the owner or agent arranges excavation, and a CDH Environmental Health Specialist must be present5. Additional or deeper holes may be required where natural soil is inadequate21. Only about 0.1% of Boise County land is rated free of severe limitations for a conventional drain field, so make septic feasibility a purchase condition rather than assuming a standard system will work8. A permit may be denied where public or central wastewater treatment is reasonably accessible22.
Can you live in an RV or tiny home on your land in Boise County?
Boise County Planning & Zoning publishes “Standards for Tiny Homes/RVs,” so do not assume rural land allows either use automatically13. We could not confirm the operative occupancy limits; ask Planning & Zoning how the standards and the parcel's zoning district apply before buying or moving in an RV or tiny home2. A manufactured home is a separate category: every installation must be inspected and approved by the state or the authority having jurisdiction before occupancy, while the state installation permit and tag apply only to new homes where no approved local building program operates9. The published Idaho camping limits concern Fish and Game lands, not residential use of private Boise County land23.
Building a home in Boise County: the steps, in order
- Schedule the required pre-application meeting with Boise County Planning & Zoning13.
- Confirm the zoning district, setbacks and Wildland-Urban Interface defensible-space requirements12.
- Apply to Central District Health, submit the plot plan and fees, and arrange the required witnessed test holes before counting on septic approval45.
- Obtain an Idaho Department of Water Resources drilling permit before drilling a well and use a licensed driller24.
- Apply for the county building permit and separate electrical, plumbing or HVAC permits; budget for plan review and staged building inspections114157.
- If the site is in a floodplain, secure the other necessary permits before the floodplain permit and do not begin work until that permit is issued25.
- Obtain an Idaho Transportation Department encroachment permit for a driveway connecting to a state highway26.
What to check before you buy land in Boise County
About 73.6% of Boise County is federal land, so verify parcel boundaries and recorded access rather than assuming an adjoining road or trail conveys private access27. Only about 0.1% of county land is rated free of severe limits for a conventional septic drain field, making a site evaluation essential before closing8. Just 11.4% of Boise County is at a slope of 15% or less, while 67.3% is wooded; inspect the build pad, driveway grade and defensible-space burden in person2829. A new well requires an IDWR drilling permit and a licensed well driller24. Boise County floodplain work cannot begin before the floodplain development permit is issued, and the county will not issue that permit until other necessary permits are obtained25. Typical home value is about $490,130, the effective property-tax rate is about 0.4%, and the median annual bill is about $1,571301011. Boise County has about 8,517 residents at 4.5 people per square mile, and the nearest city of 100,000 or more is about 34 miles from the county center313233.
Watch-outs
- Boise County's zoning record identifies Unified Land Use Ordinance #2016-01, while the Planning & Zoning page lists an 'Amended Unified Land Ordinance 2024-02'; confirm the governing edition with Planning & Zoning213.
- Only about 0.1% of Boise County's land is free of severe limitations for a conventional septic drain field; treat septic feasibility, not just permitting, as a condition of buying any specific parcel8.
- Boise County publishes standards for tiny homes and RVs, but we could not confirm their operative occupancy limits; ask Planning & Zoning before buying land to live in either13.
Sources
- Boise County Planning & Zoning - Building Permit Application Procedures (2026 county census)
- Boise County Planning and Zoning Department (2026 county census)
- Septic, Subdivisions & Water, quoted and re-checked
- Instructions for Submitting an Application for a Septic Permit, Ada & Boise County, quoted and re-checked
- Instructions for Submitting an Application for a Septic Permit, Ada & Boise County, quoted and re-checked
- (2026 county census)
- Resolution No. 2023-09: Revised Planning and Zoning Department Fee Schedule, quoted and re-checked
- Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
- Frequently Asked Questions - Building Code, quoted and re-checked
- Effective property tax rate: Bolthole Index county data
- Median property tax bill: Bolthole Index county data
- Frequently Asked Questions - Building Code, quoted and re-checked
- Boise County Planning & Zoning Department (boisecounty.us)
- Frequently Asked Questions (FAQs) - Division of Occupational and Professional Licenses (Idaho statewide rule), quoted and re-checked
- Resolution No. 2023-09: Revised Planning and Zoning Department Fee Schedule, quoted and re-checked
- Resolution No. 2023-09: Revised Planning and Zoning Department Fee Schedule, quoted and re-checked
- Septic, Subdivisions & Water, quoted and re-checked
- Central District Health - Idaho City Office (cdh.idaho.gov)
- Septic, Subdivisions & Water, quoted and re-checked
- Application - Subsurface Sewage Disposal, quoted and re-checked
- Application - Subsurface Sewage Disposal, quoted and re-checked
- IDAPA 58.01.03 Individual/Subsurface Sewage Disposal Rules (Idaho statewide rule), quoted and re-checked
- Public Use of Department Lands and Access Areas (Idaho statewide rule), quoted and re-checked
- Well Construction & Drilling, quoted and re-checked
- Boise County Permit to Develop in a Floodplain Area Application, quoted and re-checked
- Types of Right-of-Way Encroachment Permits (Idaho statewide rule), quoted and re-checked
- Federal land share: Bolthole Index county data
- Share of land at 15% slope or less: Bolthole Index county data
- Wooded share of land: Bolthole Index county data
- Typical home value (Zillow): Bolthole Index county data
- County population: Bolthole Index county data
- Population density: Bolthole Index county data
- Distance to the nearest metro area: Bolthole Index county data
Written September 29, 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.