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

Unincorporated Caribou County requires building permits for new construction, remodeling, expansions, and listed residential, accessory, prefabricated, carport, agricultural, and manufactured-building projects¹. For one- and two-family dwellings in Caribou County, Idaho adopts Parts I, II, III, and IX of the 2018 International Residential Code with amendments, collectively named the Idaho Residential Code (2020 Edition); other building types may fall under the separately adopted International Building Code^10,11. County-permitted work must pass the applicable setback, footing, foundation, framing, insulation, sheet-rock, and final inspections before advancing through the phases¹. Inspection requests require two business days' notice (48 hours), and missed inspections can trigger a stop-work order and rework at the owner's expense¹. Final inspection occurs after the building is complete and before move-in, with final electrical, plumbing, and mechanical or HVAC approvals required; the county issues a certificate of occupancy when applicable¹. Idaho exempts owners who do their own work on their own land, and do not intend to sell within 12 months, from contractor registration, but that exemption does not waive Caribou County building permits, zoning, septic or inspections⁹.

For county-administered building applications and inspections, contact the Caribou County Building Department; call (208)840-9910 or email rlarkins@caribouid.gov during its Monday-through-Friday, 6:30 a.m.-to-2:30 p.m. hours⁸. In-person applications go to the Caribou County Courthouse at 159 South Main Street, Rm #100, Soda Springs, Idaho 83276⁸. The Planning & Zoning Department uses the same courthouse room but has a separate line at (208) 547-1780 and email at hbarker@caribouid.gov; its hours are Monday through Friday, 9 a.m. to 5 p.m⁸.. Applications may be sent by email or mail or delivered in person⁸. County review can take up to 10 business days, and processing starts only after staff verifies completeness and receives payment⁸. Building fees follow a statewide adopted schedule, while the zoning-permit application lists a $25 fee payable with the building permit; the amount can vary by permit and project¹. Inside Bancroft, the city's own building-permit requirements apply before construction, alteration, or moving structures⁴. Septic permitting remains with Southeastern Idaho Public Health⁵.

Caribou County zoning applies throughout unincorporated land, with uses and construction governed by the parcel's district². Inside Grace and Bancroft, city zoning applies; both cities' zoning provisions also address impact areas, so ask Planning & Zoning which standards govern a parcel near city limits^12,13. Septic permitting remains with Southeastern Idaho Public Health⁵. Agricultural residential use requires one dwelling per 40 acres². Other district-specific lot standards depend on septic and utility service; ask Planning & Zoning to identify the applicable district before relying on an acreage threshold^2,3. The Light Industrial and Wholesale district has no minimum lot size, but lots must accommodate business functions without impeding road rights-of-way or the site triangle². Setbacks depend on district, building type, use, and road right-of-way; structures generally must remain 100 feet from streams or riparian areas, except compliant approved culverts^2,14. Accessory dwelling units within single-family structures are permitted in at least one district, with district-specific approval still required².

A septic permit is required for every Caribou County residential permit that needs septic service; an addition instead needs a Southeastern Idaho Public Health letter confirming that the existing system can support it¹. Idaho DEQ sets the statewide onsite-sewage rules, while Southeastern Idaho Public Health conducts site evaluations, issues permits, and inspects installations in Caribou County⁵. Apply through SIPH's Caribou County office at 55 East 1st South, Soda Springs, Idaho 83276, or call (208) 547-4375¹⁵. A complete application needs a signed plot plan, deed or tax notice, fee, and onsite evaluation⁶. The applicant supplies test holes 8 to 10 feet deep, depending on soil type⁶. The SIPH page states $925 for a full site evaluation and permit if suitable but also lists $850 for a basic or complex permit, so confirm the current charge before applying⁶. Only 22.6% of county land is rated without severe limitations for a conventional drain field, making an early evaluation useful¹⁶.

Unincorporated Caribou County allows one occupied travel trailer per lot for no more than 120 days in a calendar year². A separate construction option in unincorporated Caribou County lets an RV with a kitchen and bathroom serve as a temporary residence at the Planning and Zoning Administrator's discretion while a permanent site-built home is underway². That option requires separate building and zoning permits and cannot start until the permanent home's foundation or basement walls pass inspection². The RV must normally be vacated and removed within 12 months; stalled or abandoned home construction for 180 days voids both permits, and the commission may grant one one-year extension for circumstances outside the applicant's control². A campground or RV park is only a conditional Agricultural-district use, not permission for unrestricted residence on an individual parcel⁷. We could not confirm a separate tiny-home rule or minimum dwelling floor area, so ask Planning & Zoning how a proposed tiny home would be classified and which district standards would apply³.

1. Ask Planning & Zoning to confirm the mapped district, allowed use, lot standard, setbacks, and height limit^2,3,14.
2. Arrange SIPH's required onsite evaluation and supply the application, plot plan, ownership record, fee, and test holes⁶.
3. Ask the Idaho Department of Water Resources to distinguish well-drilling permits from domestic-use water-right exemptions for the parcel; wells require an IDWR-licensed driller^17,18.
4. Submit the county application by email, mail, or in person and pay after completeness review so processing can begin⁸.
5. Design for the county's 36-inch frost depth, 60 psf roof snow load, 87 psf ground snow load, 115 mph wind, and D1 seismic criteria⁸.
6. If living in an RV during construction, obtain separate building and zoning permits and wait for the foundation or basement-wall inspection².
7. Obtain a state encroachment permit for access onto a state highway¹⁹.
8. Schedule each county inspection with two business days' notice (48 hours) and complete final inspection before move-in; a certificate of occupancy is issued when applicable¹.

Start with the zoning map rather than acreage alone because lot size, setbacks, permitted uses, and height limits vary by district^2,3,14. Verify streams and riparian areas on the building envelope because structures generally require a 100-foot separation². Only 22.6% of Caribou County land is rated without severe limitations for a conventional drain field, so make SIPH's required site evaluation an early contingency^6,16. Annual precipitation is about 22.8 inches, and severe drought occurs in 8.2% of years, so confirm the proposed water source and applicable approvals¹⁶. An Agricultural-district subdivision must have a single access built to county standards connecting to a county-maintained road, while access to a state highway needs a state encroachment permit^7,19. We could not confirm a county floodplain-development rule for unincorporated land; ask Planning & Zoning about the parcel before closing⁸.