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

At a glance

Building permit

Required before construction begins in unincorporated Blaine County¹

Zoning

County zoning districts and overlays apply in unincorporated areas²⁵

Septic

A public-health-district permit and inspection are required⁴⁶

RV living

Countywide rules for residential RV use could not be confirmed; ask Land Use²

Tiny home

Permission depends on zoning and building review; a complete occupancy rule could not be confirmed²¹

Agricultural building

A district-specific building-permit exemption may apply, but a setback permit is still required⁷

Private well

Obtain an IDWR drilling permit before drilling⁸

Who to call

Contact details are copied from each office’s official page and were checked against it on September 27, 2026.

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

Yes. A building permit is required before construction begins in unincorporated Blaine County.¹ County Building Services administers permits and accepts digital plans through OpenGov.³ Construction covered by the county building code also requires a certificate of occupancy.⁹

One narrow exception applies to qualifying agricultural buildings in the A-20, A-40, R-10 and RR-40 zoning districts: those buildings do not require a building permit when they meet the county definition, but they still need a $25 setback permit through Building Services.⁷ Agricultural buildings outside those listed districts require building permits.⁷ Do not assume that calling a structure a barn makes it exempt; confirm the parcel's zoning district and the proposed use with Land Use before ordering materials.⁷¹⁰

Who is the Blaine County building department and how do you reach it?

Blaine County Building Services is the permit and inspection office for covered construction in unincorporated Blaine County.¹ The office accepts digital plans only through the county's OpenGov portal.³ Building inspections can be requested at 208-788-5573, extension 1125.³

Land-use review is separate but closely connected. Blaine County Land Use accepts building and land-use applications electronically and can answer parcel-zoning, overlay, setback and floodplain questions at 208-788-5570.¹⁰ The building application may require road, utility, fire-district, Idaho water-resources and South Central Public Health District information or approvals before issuance.¹¹ Incomplete applications can take longer, and additional plan review may add fees.¹¹

Does Blaine County, Idaho have zoning?

Yes. Zoning districts and overlay districts govern land in unincorporated Blaine County, while incorporated municipalities may administer their own land-use rules.² District-specific permitted uses, conditional uses, dimensional standards and exceptions apply.⁵

Setbacks therefore cannot be reduced to one countywide number.¹² The reviewed district standards include a 100-foot setback from State Highway 75, a 30-foot setback from federally managed or Idaho Department of Lands public land, and a 50-foot property-line setback for mobile or manufactured homes in the cited agricultural and rural districts.¹² Floodplain and riparian, mountain, scenic-highway and avalanche overlays may add another review layer.⁵ Ask Land Use to identify the base district and every overlay for the parcel before placing a home, driveway, septic area or outbuilding.¹⁰

How do septic permits work in Blaine County?

South Central Public Health District administers Idaho's onsite wastewater rules for Blaine County, and a property owner must obtain a district permit before installing an individual septic system.¹³⁴ The district inspects the system after installation.⁶ The Bellevue office handles septic and land-development questions for the district at (208) 788-4335 or [email protected].¹⁴

Site feasibility deserves early attention: only about 1.9% of mapped county soils avoid a severe USDA limitation rating for a conventional septic drain field.¹⁵ That rating does not decide whether a particular parcel can pass, but it makes a site evaluation and system design an early due-diligence priority.¹⁵ A proposed large soil absorption system at or above 2,500 gallons per day faces added evaluation, installer and state-review requirements.⁴

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

We could not confirm a complete countywide rule for long-term RV occupancy, temporary camping on private land or tiny-home occupancy in unincorporated Blaine County. Ask Blaine County Land Use to review the parcel's zoning district, overlays and proposed duration before buying or moving a unit onto the land.¹⁰ County zoning applies in unincorporated areas, so silence in a general FAQ is not permission.²

A narrower reviewed rule applies to mobile and manufactured homes in the A-40 district.¹⁶ Temporary use during construction is limited to one year, while permanent primary-residence use requires at least 40 acres and certification to current county building standards.¹⁶ Other district rules and setbacks can also apply.¹⁶ Idaho requires manufactured-home installations to be inspected and approved before occupancy.¹⁷

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

1. Ask Blaine County Land Use to confirm that the parcel is a legal lot, identify its zoning district and overlays, and flag any land-use or floodplain approvals.¹⁸⁵¹⁹
2. Have South Central Public Health District evaluate the site and issue the required septic permit if the property will use onsite wastewater.⁴
3. Obtain an IDWR drilling permit before drilling a private well, and use an IDWR-licensed well driller.²⁰
4. Resolve access: a driveway connecting to state highway right-of-way requires an Idaho Transportation Department encroachment permit.²¹ Ask the county about access from a county road because a complete county rule could not be confirmed.
5. Submit the building application and digital plans through OpenGov with the outside approvals the application requires.³¹¹
6. Schedule inspections and obtain the required certificate of occupancy before treating the project as complete.³⁹

What should you check before buying land in Blaine County?

Start with zoning, overlays and legal access, then put septic and water feasibility ahead of house plans.⁵¹⁸⁴ Only about 1.9% of mapped soils avoid severe limitations for a conventional drain field, and about 42.8% of county land has a slope of 15% or less.¹⁵²² Those countywide figures are screening signals, not substitutes for parcel-level soil and topographic work.¹⁵²²

Check floodplain status before designing: development in the Floodplain Overlay District can require a conditional-use application, detailed elevation information and a lowest floor at least 2 feet above the applicable base flood elevation or highest adjacent grade.¹⁹ A private well needs an IDWR drilling permit.⁸ For budgeting context, the county's effective property-tax rate is about 0.4%, with a median annual property-tax bill of $2,563.²³²⁴

Watch-outs

• A building permit becomes void if authorized work has not begun within 180 days, subject to a possible extension under county code.¹¹
• Building-permit charges include a plan-check fee equal to 65% of the building permit fee and a fire-department plan-check fee equal to 40% of the plan-check fee.²⁵
• Do not rely on a countywide answer for RV living, tiny-home occupancy, minimum dwelling size or owner-builder status; ask Land Use and Building Services about the exact parcel and project.¹⁰³

Sources

1. Blaine County Building Services (2026 county census)
2. Blaine County Ordinance No. 2025-08 (2026 county census)
3. Blaine County Building Services (blainecountyid.gov)
4. Septic and Septage, quoted and re-checked
5. Blaine County Ordinance No. 2025-08, quoted and re-checked
6. Septic and Septage, quoted and re-checked
7. Frequently Asked Questions, quoted and re-checked
8. Wells Overview, quoted and re-checked
9. Blaine County Building Services Building Permit Application, quoted and re-checked
10. Blaine County Land Use (blainecountyid.gov)
11. Blaine County Building Services Building Permit Application, quoted and re-checked
12. Blaine County Ordinance No. 2025-08, quoted and re-checked
13. Septic and Septage, quoted and re-checked
14. South Central Public Health District (phd5.idaho.gov)
15. Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
16. Blaine County Ordinance No. 2025-08, quoted and re-checked
17. Building Archives - Division of Occupational and Professional Licenses (Idaho statewide rule), quoted and re-checked
18. Blaine County Ordinance No. 2025-08, quoted and re-checked
19. Blaine County Ordinance No. 2025-08, quoted and re-checked
20. Wells Overview (Idaho statewide rule), quoted and re-checked
21. Types of Right-of-Way Encroachment Permits (Idaho statewide rule), quoted and re-checked
22. Share of land at 15% slope or less: Bolthole Index county data
23. Effective property tax rate: Bolthole Index county data
24. Median property tax bill: Bolthole Index county data
25. Local Jurisdictional Fees, quoted and re-checked

Written September 27, 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.