State Guide · Verified 2026
Shed Installation Permits in Idaho
The Building Code in Idaho
2018 International Residential Code with Idaho amendments, adopted by state statute
Idaho adopts its building codes through the state legislature rather than by administrative rulemaking, a slower and more deliberate process than most states use. The current statewide code remains the 2018 IRC, IBC, IECC, IMC, and IFGC, alongside the 2023 National Electrical Code and the 2017 Idaho State Plumbing Code, after a proposed move to the 2024 editions was rejected by the legislature in February 2026. Under the 2018 Idaho Residential Code, Section R105.2, a one-story detached storage shed of 200 square feet or less is exempt from the building permit specifically, a distinct provision from Idaho Code 39-4116, which governs how local governments adopt and enforce the codes generally rather than setting the shed threshold itself.
Quick Facts
Who Sets the Rules
A code adopted by the legislature, not an agency
Idaho is distinctive in adopting its building codes through statute rather than administrative rulemaking, which means a new code edition needs legislative approval before it can take effect, a slower and more politically exposed process than most states use.
A very recent, very current decision to stay on 2018
A proposed move to the 2024 I-Codes was brought before the Idaho legislature and rejected in February 2026, just months before this research, meaning the 2018 editions remain the active statewide standard for the foreseeable future rather than by default inaction.
The 200-square-foot line comes from the residential code itself
The shed exemption is codified at Section R105.2 of the 2018 Idaho Residential Code specifically, distinct from Idaho Code 39-4116, which governs the broader process for how local governments adopt and enforce building codes rather than setting the shed number itself, a distinction that some secondary sources blur together.
Kootenai County goes further than almost anywhere in the country
Kootenai County, home to Coeur d'Alene and Post Falls, allows owners of residential property to build without a building permit at all, provided they still obtain a location permit confirming zoning and setback compliance, a genuinely rare level of opt-out authority even compared to other property-rights-focused states.
Trade permits run through the state even when the shed itself is exempt
In most Idaho jurisdictions, electrical work goes through the state DOPL electrical program rather than a local building department, and the same is generally true for plumbing under the state plumbing code, meaning a building-permit-exempt shed can still need separate state-issued trade permits.
What people get wrong
The most common mistake is treating Idaho Code 39-4116 as the source of the 200-square-foot shed number. It is not: that statute governs code adoption generally, while the actual shed threshold comes from the residential code's own exemption section, a distinction that matters if you're trying to cite the rule directly.
Counties With Their Own Rules
These Idaho counties have verified, county-specific shed installation rules that differ from the state baseline:
Check Your County
Select your county for the local rule, fees, and your building department's contact details:
Building It Yourself? Here's What You'll Need
Popular tools and materials homeowners use for a shed installation project:
As an Amazon Associate, we earn from qualifying purchases.
Official Sources
Rules change and cities within a county may differ. This guide is general information, not legal advice — always confirm with your local building department. Reviewed by the StateDataIndex Editorial Team · Updated September 2026.