Building permits in Bonneville County, Idaho
Find the right authority before you build. Bonneville County permitting follows Idaho law — here is exactly who issues the permit and where to start.
County + cities (mixed)
Bonneville County — Planning & Zoning (Building Division) (and City of Idaho Falls Building Department)
In unincorporated Bonneville County, building permits are issued by the Bonneville County Planning & Zoning (Building Division). Within the City of Idaho Falls (and other incorporated cities such as Ammon) the municipal building department issues the permit. Note: as of January 2026 Bonneville County also processes electrical and plumbing permits locally.
Permit cheat-sheet (Idaho rules)
| Project | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| 🏠 Accessory Dwelling Unit (ADU) | Permit required | city | Valuation-based; set by the issuing city or, in unincorporated areas, by Idaho DOPL. | Plan review typically 1–3 weeks in Treasure Valley cities. | Generally allowed | Idaho has no single statewide ADU mandate; cities adopt ADU rules by local ordinance. Boise and other growing cities allow ADUs subject to zoning. Verify with the local building department. Exempt: No statewide size exemption; local zoning sets ADU size and lot limits. |
| 🪵 Deck / Porch | Conditional | city | Valuation-based; set by the issuing city. | Over-the-counter or plan review depending on complexity. | Generally allowed | Attached decks with a structural ledger connection should be verified with the building department; mountain areas require local snow-load design. Exempt: Decks ≤30 in above grade (not serving as an exit) are exempt under the Idaho Residential Code. |
| 🧱 Fence / Wall | Conditional | city | Most low fences are exempt; over-height fences follow the city valuation-based permit fee. | Over-height fences go through plan review. | Generally allowed | Utility locates (811) and property-line verification are required before digging. Verify with the local building department. Exempt: Most Idaho cities exempt fences ≤6 ft; Boise exempts fences <7 ft (front-yard fences often limited to 4 ft). |
| 🛖 Shed / Outbuilding | Conditional | city | Valuation-based; set by the issuing city (small sheds often exempt). | Exempt sheds need no permit; permitted sheds go through plan review. | Generally allowed | Even exempt sheds must meet zoning setbacks and local snow-load design (20 psf in the Treasure Valley, much higher in mountain areas). Verify with the local building department. Exempt: Idaho Residential Code exempts one-story detached accessory structures ≤200 sq ft (storage, no plumbing/electrical). Some cities use a 120 sq ft threshold. |
| 🪜 Basement Finish | Permit required | city | Valuation-based; includes trade permits. | Standard plan review. | Generally allowed | Basement finishing requires permits when it creates habitable space. Verify with the local building department. Exempt: Cosmetic finishing (paint, flooring) is exempt. |
| 🚗 Garage / Carport | Permit required | city | Valuation-based; includes trade permits. | New-structure plan review; varies by city. | Generally allowed | Attached and detached garages require a full building permit and plan review. Verify with the local building department. Exempt: New detached structures over the exemption threshold (120–200 sq ft) require a permit. |
| ☀️ Rooftop Solar PV | Permit required | city | Building + electrical permits; Boise residential solar PV plan-review/inspection fee ~$165. | Residential PV is typically expedited; Boise reviews standard rooftop systems quickly. | Generally allowed | Electrical permits are handled by Idaho DOPL (or the city where it has trade jurisdiction). Verify with the local building department. Exempt: No size exemption; large/ground-mounted systems need structural review. |
| 🌡️ HVAC Replacement | Conditional | city | Mechanical permit; fee set by city or Idaho DOPL (trade permit). | Trade permits often issued same-day. | Generally allowed | Homeowners may pull their own HVAC permit on a primary residence in many Idaho jurisdictions. Verify with the local building department. Exempt: In-kind replacement in the same location may be exempt; verify locally. |
| 🍳 Kitchen Remodel | Conditional | city | Valuation-based when structural/plumbing/electrical work is included. | Standard review for permitted scopes. | Generally allowed | Idaho’s energy code is reviewed on remodels. Verify with the local building department. Exempt: Cabinet/countertop swap in the same layout is exempt. |
| 🛁 Bathroom Remodel | Conditional | city | Valuation-based when plumbing is relocated. | Standard review for permitted scopes. | Generally allowed | Ventilation to the exterior is required. Verify with the local building department. Exempt: Fixture-for-fixture swap in place is often exempt. |
| 🏗️ Room Addition | Permit required | city | Valuation-based; includes trade permits. | City plan review; multiple inspections. | Generally allowed | Lot-coverage and energy-code compliance are reviewed. Verify with the local building department. Exempt: No exemption — any new conditioned footprint requires a permit. |
| 🪟 Window / Door Replacement | Conditional | city | Usually no fee for in-kind swap; permit needed if opening is enlarged. | In-kind swaps typically need no review. | Generally allowed | Replacement products should meet energy-code U-factor when the code is triggered. Verify with the local building department. Exempt: Same-size, in-kind replacement is generally exempt. |
| 🏘️ Roof Replacement | Conditional | city | Often exempt/over-the-counter for same-footprint re-roof; fee set by city if required. | Same-material re-roof is often exempt or over-the-counter. | Generally allowed | Local snow-load design applies to any structural roof change. Verify with the local building department. Exempt: Same-material, same-slope re-roof often exempt under the IRC. |
| 🅿️ Driveway / Parking Pad | Conditional | city | Building permit often not required; curb-cut/right-of-way work is separate. | Right-of-way permits reviewed by the city/county. | Generally allowed | A separate right-of-way permit is usually needed to cut the curb or connect to the street. Verify with the local building department. Exempt: Slabs/walks/driveways not more than 30 in above grade (and not over a basement) are exempt; concrete slabs are commonly exempt. |
| 🏊 Swimming Pool / Spa | Permit required | city | Valuation-based; includes barrier/fencing and electrical bonding review. | Plan review; barrier inspection required before filling. | Generally allowed | Idaho follows IRC barrier requirements (4 ft minimum, no climbable openings). Verify with the local building department. Exempt: Above-ground prefab pools <24 in deep and <5,000 gal (R-3) are typically exempt. |
| 🧱 Retaining Wall | Conditional | city | Valuation-based when over the height threshold. | Over-threshold walls need plan review. | Generally allowed | Walls in hillside/WUI zones have stricter rules. Verify with the local building department. Exempt: Walls ≤4 ft (measured from bottom of footing to top) and not supporting a surcharge are commonly exempt. |
| 💥 Demolition / Teardown | Permit required | city | Demolition permit fee set by the issuing authority; verify locally. | — | Generally allowed | A full teardown or major strip-out requires a demolition (building) permit. Demolition permits commonly require proof of utility disconnects (water, gas, electric, sewer) and may require asbestos/lead-paint clearance for pre-1978 homes before work begins. Verify the issuing authority for your specific property. |
| 🚰 Septic System | Permit required | county | Septic permit fee set by the local environmental/health authority; engineered systems cost more. | — | Generally allowed | New or replacement onsite wastewater (septic) systems require a permit from the state environmental/health department (or local health district). A soil/perc evaluation and engineered design are typically required; licensed installers perform the work and the system is inspected before backfill. |
| 🔌 EV Charger | Conditional | city | Electrical permit; fee set by the issuing authority. | — | Generally allowed | A home EV charging station (240V branch circuit + wall-mounted EVSE) requires an electrical permit and must meet the NEC (Article 625). Many jurisdictions fast-track residential EVSE. A load calculation and possible service upgrade are reviewed. |
| ⚡ Standby Generator | Conditional | city | Mechanical/electrical permit; fee set by the issuing authority. | — | Generally allowed | A permanently installed standby generator requires mechanical and electrical permits (transfer switch, fuel gas/propane line). Setback, carbon-monoxide ventilation, and noise rules apply; some HOAs restrict generator placement. |
Frequently asked questions
Who issues building permits in Bonneville County, Idaho?
Bonneville County — Planning & Zoning (Building Division) (and City of Idaho Falls Building Department) is the permitting authority for Bonneville County. Permitting is split — cities issue for incorporated areas, the county for unincorporated areas. Start at the official portal linked above.
Do I go to the county or my city for a building permit in Bonneville County?
Permitting is split — cities issue for incorporated areas, the county for unincorporated areas.
What home projects need a permit in Bonneville County?
The same project types shown in the cheat-sheet above (ADU, deck, fence, shed, solar, and more) — rules follow Idaho state law. Whether the county or your city issues it depends on your property's incorporation status.
How do I apply for a permit in Bonneville County?
Use the official permit portal linked above. Most offices accept online submissions; have your plans, site information, and contractor details ready before applying.