Building permits, zoning and septic rules in Caribou County, Idaho

At a glance

Building permit

Required for new construction, additions, shops, remodels, and agricultural structures, through the county Building Department¹

Zoning

Yes, countywide in unincorporated areas; Caribou County has its own zoning districts, comprehensive plan, and map⁵

Septic permits

Southeastern Idaho Public Health (SIPH); $850 for a basic or complex system, $3,000 for large soil absorption, $300 for tank only⁴⁶

Minimum lot size

40 acres for a single-family dwelling in the Agricultural district; 20 acres in the Low-Density Residential district⁷

Setbacks (Agricultural district)

40 ft from an arterial road, 50 ft from a local or collector road, 30 ft rear yard, 20 ft side yard for a single-family residence⁷

RV living

One occupied travel trailer per lot, limited to 120 days per calendar year; a separate temporary-construction path can allow up to 12 months³⁸

Structural design minimums

36-inch frost depth, 60 psf roof snow load, 87 psf ground snow load, 115 mph wind design, seismic zone D1⁹

Owner-builder exemption

Unconfirmed; no Caribou County source states one exists¹⁰

Who to call

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 Caribou County, Idaho?

Yes. Caribou County's Building Department receives and reviews building permit applications for new construction, additions, shops, remodels, agricultural structures, and other projects in unincorporated areas, and it performs building inspections¹. Idaho has adopted the 2018 International Building Code and 2018 International Residential Code, with Idaho amendments¹¹. Caribou County's building checklist sets structural design minimums for all county buildings: a 36-inch frost depth at the bottom of footings, a 60-pound-per-square-foot roof snow load, an 87-pound-per-square-foot ground snow load, a 115-mph wind design with three-second gusts, and seismic design for zone D1⁹. Applications may be submitted by email, mail, or in person, but an application is not officially submitted and processing does not start until payment is received⁹. After an applicable county-permitted building is complete, the county conducts the final inspection before move-in and issues a certificate of occupancy when applicable¹². Idaho also requires permits when electrical, plumbing, or HVAC work is performed, although local administration varies by location¹³. Caribou County has not confirmed an owner-builder exemption, so ask the Building Department before planning to act as your own contractor¹⁰.

Who is the Caribou County building department, and how do you reach them?

The Caribou County Building Department handles permit applications, plan review, and inspections, reachable at (208)840-9910 or [email protected], with office hours Monday through Friday, 6:30 a.m. to 2:30 p.m.⁹. In-person applications go to the Caribou County Courthouse at 159 South Main Street, Rm #100, Soda Springs, Idaho 83276⁹. The Planning & Zoning Department shares the same building and application process but is a separate line, at (208) 547-1780 or [email protected], Monday through Friday, 9 a.m. to 5 p.m.¹⁴. Both departments post their permit checklists and application forms on the county's Building, Planning & Zoning page, and both require payment before an application is considered officially submitted⁹¹⁴.

Does Caribou County have zoning?

Yes. Caribou County zoning applies throughout unincorporated Caribou County². The compiled ordinance publishes Agricultural, Low-Density Residential, and other districts with their own lot-size, setback, use, and height standards; municipal area-of-impact agreements and municipal ordinances appear separately¹⁵. The rules differ sharply by district: in the Agricultural district, the minimum lot size for a single-family dwelling is 40 acres, at a density of one dwelling per 40 acres, while the Low-Density Residential district allows a 20-acre minimum lot, one dwelling per 20 acres⁷. In the Agricultural district, a single-family residence needs a 40-foot setback from an arterial road, 50 feet from a local or collector road, a 30-foot rear-yard setback, and a 20-foot side-yard setback⁷. Land-use fees are published too: a concept subdivision plat runs $210 plus $26 per lot for the first five lots (and $10 per additional lot), a conditional use permit is $365, and a zone change is $630⁷. Confirm the parcel's district and the controlling standards with the Planning & Zoning Department before buying or designing a build¹⁵.

How do septic permits work in Caribou County?

Septic systems in Caribou County are permitted by Southeastern Idaho Public Health, one of Idaho's seven regional public health districts that administer the state's onsite wastewater rules under IDAPA 58.01.03⁴¹⁶. Caribou County applications are handled at SIPH's Soda Springs office, 55 East 1st South, Soda Springs, Idaho 83276, (208) 547-4375¹⁷. SIPH's districtwide fee schedule sets a $850 fee for a basic or complex system, $3,000 for a large soil absorption system, $300 for a tank-only permit, $300 for a speculative site evaluation, and $40 to renew an existing permit⁶. No system may receive wastewater until a final installation inspection is conducted, and if any part of the system needs to be uncovered for that inspection, the applicant must give at least 48 hours' advance notice, excluding weekends and holidays¹⁸. Soils are workable here overall: 22.6% of Caribou County's land is free of severe limitations for a conventional drain field, better than many rural counties, but still worth a site evaluation before you commit to a design¹⁹. Idaho law also lets SIPH deny a septic permit where public or central wastewater treatment is reasonably accessible, so check with the district if your parcel is near an existing sewer system²⁰.

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

Unincorporated Caribou County allows one occupied travel trailer on a lot in any zoning district for no more than 120 days within a calendar year³. A separate construction rule allows a recreational vehicle with a kitchen and bathroom to serve as a temporary residence while a permanent site-built home is under construction, at the Planning and Zoning Administrator's discretion⁸. The construction arrangement requires separate building and zoning permits, cannot begin before the permanent home's foundation or basement walls pass inspection, and must end within 12 months after the temporary permit is issued⁸. If work on the permanent residence is suspended or abandoned for 180 days, both permits become void; the Planning and Zoning Commission may grant one one-year extension for circumstances beyond the applicant's control⁸. Idaho requires every manufactured-home installation to be inspected and approved before occupancy²¹. Caribou County has not confirmed a specific tiny-home occupancy rule or general minimum dwelling size, so ask Planning & Zoning how the proposed unit is classified before buying or building⁵.

Building a home in Caribou County: the steps, in order

First, confirm your zoning district and its minimum lot size and setbacks with the Planning & Zoning Department, since the Agricultural district requires 40 acres and the Low-Density Residential district requires 20 acres for a single-family dwelling¹⁴⁷. Second, if you need septic, contact Southeastern Idaho Public Health's Soda Springs office for a site evaluation before finalizing your house design, and budget for the $850 basic or complex system fee, or $3,000 if a large soil absorption system is needed¹⁷⁶. Third, submit your building permit application to the Building Department by email, mail, or in person at the Caribou County Courthouse, along with payment, since applications aren't officially submitted until payment is received⁹. Fourth, design to the county's structural minimums: 36-inch frost depth, 60 psf roof snow load, 87 psf ground snow load, 115 mph wind design, and seismic zone D1⁹. Fifth, if you'll need a temporary RV or manufactured home on site while building, get the separate temporary-residence permit from Planning & Zoning before moving in, and plan to remove it within 12 months⁷. Sixth, if your driveway will connect to a state highway, apply for an Idaho Transportation Department encroachment permit before any work begins on the right-of-way²². Seventh, schedule septic inspection with SIPH before the system receives wastewater, then complete the county's final building inspection before moving in and obtain a certificate of occupancy if one applies¹⁸¹².

What to check before you buy land in Caribou County

Start with zoning district and lot size, since a parcel zoned Agricultural needs 40 acres for a single-family home while Low-Density Residential only needs 20, and any lot smaller than the applicable minimum may not be buildable as a standalone home site⁷. Water can be a real constraint: annual precipitation runs only about 22.8 inches, and 8.2% of years bring severe drought, so a well test matters more here than in wetter counties²³²⁴. Idaho requires a drilling permit from the Department of Water Resources before any well is drilled, so factor that into your timeline if the land doesn't already have one²⁵. Terrain is mixed, with 46.2% of the county at 15% slope or less, and a large share of the county, 42.3%, is federal land, which narrows the private, buildable footprint in some areas²⁶²⁷. Soils are workable for septic on much of the county, with 22.6% free of severe drain-field limitations, but still confirm with a site evaluation before you count on a basic system¹⁹. Property taxes run moderate: an effective rate near 0.6% and a median annual bill around $1,330, against a typical home value around $341,144²⁸²⁹³⁰.

Watch-outs

• No Caribou County source confirms an owner-builder exemption from the building-permit process; ask the Building Department directly before assuming you can act as your own contractor without a permit¹⁰.
• Unincorporated Caribou County limits one occupied travel trailer on a lot to 120 days per calendar year; the separate construction-residence permit has different conditions and a 12-month removal deadline³⁸.

Sources

1. Caribou County - Building, Planning & Zoning (2026 county census)
2. Development Services, quoted and re-checked
3. Caribou County Zoning Ordinances, Comprehensive Plan & AOI Agreements, quoted and re-checked
4. Southeastern Idaho Public Health - Septic Permits (2026 county census)
5. Development Services (2026 county census)
6. Southeastern Idaho Public Health, Septic/Onsite Wastewater Program (siphidaho.org)
7. Caribou County Zoning Ordinance (Ord. 2019-02, amended Ord. 2020-01) (cms7files.revize.com)
8. Caribou County Zoning Ordinances, Comprehensive Plan & AOI Agreements, quoted and re-checked
9. Caribou County Building Department (cariboucounty.us)
10. (2026 county census)
11. Idaho Adopted Codes (Idaho statewide rule), quoted and re-checked
12. Caribou County Building Checklist, quoted and re-checked
13. Frequently Asked Questions (FAQs) - Division of Occupational and Professional Licenses (Idaho statewide rule), quoted and re-checked
14. Caribou County Planning & Zoning Department (cariboucounty.us)
15. Caribou County Zoning Ordinances, Comprehensive Plan & AOI Agreements, quoted and re-checked
16. Septic and Septage (Idaho statewide rule), quoted and re-checked
17. Southeastern Idaho Public Health, Caribou County Office (siphidaho.org)
18. IDAPA 58.01.03 Individual/Subsurface Sewage Disposal Rules (Idaho statewide rule), quoted and re-checked
19. Share of soils without severe limits for a conventional septic drain field (USDA SSURGO): Bolthole Index county data
20. IDAPA 58.01.03 Individual/Subsurface Sewage Disposal Rules (Idaho statewide rule), quoted and re-checked
21. Building Archives - Division of Occupational and Professional Licenses (Idaho statewide rule), quoted and re-checked
22. Types of Right-of-Way Encroachment Permits (Idaho statewide rule), quoted and re-checked
23. Annual precipitation: Bolthole Index county data
24. Share of years in severe drought: Bolthole Index county data
25. Wells Overview (Idaho statewide rule), quoted and re-checked
26. Share of land at 15% slope or less: Bolthole Index county data
27. Federal land share: Bolthole Index county data
28. Effective property tax rate: Bolthole Index county data
29. Median property tax bill: Bolthole Index county data
30. Typical home value (Zillow): 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.