Idaho Shed Permit Rules: What Homeowners Need to Know

A Statutory Exemption and a Property Rights Culture

Idaho's approach to shed permits reflects the state's broader philosophy toward property rights and limited government regulation. The 200-square-foot exemption isn't just a common local practice — it's codified in state law. Under Idaho Code §39-4116, residential accessory buildings less than 200 square feet, like sheds and playhouses, are exempt from building permit requirements statewide. This statutory backing gives the exemption more weight than in states where each city sets its own threshold.

Local jurisdictions enforce the code through their own building departments, and each city adds its own zoning overlay for setbacks, lot coverage, and placement. But the 200-square-foot building permit exemption is consistent from Boise to Coeur d'Alene.

What makes Idaho truly distinctive is how far some jurisdictions take the property rights approach. Kootenai County has an ordinance allowing homeowners of single-family residential parcels to build without obtaining a building permit at all, with only a location permit required. This opt-out provision is rare in the United States and underscores the diversity of building regulation philosophy even within a single state.

The Idaho Division of Building Safety provides state-level oversight of building codes and contractor licensing. For a broader look at how Idaho compares nationally, see our national guide to shed permits.

How Five Idaho Cities Handle Shed Permits

Boise: Standard 200-Square-Foot Exemption

Boise follows the state statute with a clean 200-square-foot exemption for one-story detached sheds with no utilities. Sheds over 200 square feet need a building permit with plans showing the structure's dimensions, foundation, framing, and anchoring. Permit fees are valuation-based, typically running $75–$200 for residential accessory structures, with reviews taking 1–3 weeks. The city requires all accessory buildings to be in the rear yard, meeting the setback distances established for the zoning district.

Meridian: The Clearest Foundation Rules in Idaho

Meridian stands out for having one of the most clearly documented shed permit processes in the state. The city publishes a detailed handout that spells out a three-tier foundation system based on shed size and utilities:

• 200 square feet or less: No building permit required. Setback and HOA rules must be observed. Any electrical work requires an electrical permit.
• 200–600 square feet, unheated, no power: Requires an R-SHED building permit. A shallow slab foundation with turned-down edges to 12 inches deep is required. The shed must be adequately attached to the foundation.
• 200–600 square feet, with power and heat: Requires an R-SHED permit plus an electrical permit. Footings must extend to the frost line at 24 inches deep.
• Over 600 square feet: Full footing and foundation to frost line (24 inches) regardless of utility connections.

This clarity is unusual — most cities leave homeowners guessing about foundation requirements. Meridian also limits each property to one detached accessory structure of 200 square feet or less in the required rear yard without a permit.

Nampa: Floodplain and Electrical Triggers

Nampa follows the 200-square-foot exemption with two important exceptions. If the shed is in a floodplain, a permit is required regardless of size. If the shed is wired for electricity, an electrical permit is needed even for structures under 200 square feet. Standard shed permits are processed in 5–10 business days with fees of $50–$150.

Idaho Falls: Eastern Idaho's Largest City

Idaho Falls applies the state exemption consistently. Most accessory buildings under 200 square feet don't need a permit. The city's building department processes permits for larger sheds with valuation-based fees and 1–2 week review times. Idaho Falls' location in eastern Idaho means higher snow loads than the Treasure Valley, and the city's building department verifies roof framing adequacy during permit review.

Twin Falls: No Zoning Permit for Small Sheds

Twin Falls goes a step further than many Idaho cities by exempting small sheds from the zoning use permit as well as the building permit, provided all conditions are met: the shed must be under 200 square feet, single story, under 15 feet tall, and used for storage only. The property owner remains responsible for meeting setback requirements, and the city reserves the right to require the owner to move or relocate any accessory building found to be in violation.

Twin Falls uses the 2018 editions of both the IRC and IBC for residential and commercial construction. The city's detached accessory building regulations require at least 10 feet of separation between accessory buildings and other structures.

Foundation Requirements: Idaho's Moderate Frost Depth

Idaho's frost depth varies significantly by location but is generally more moderate than states like Wisconsin or Minnesota.

In the Treasure Valley (Boise, Meridian, Nampa, Caldwell), the frost line is approximately 24 inches below grade. This is the depth that Meridian specifies for shed foundations that need to reach frost line. It's substantially less than the 42–48 inches required in upper Midwest states, making foundation construction more affordable.

In northern Idaho (Coeur d'Alene, Moscow, Lewiston), frost depths increase to 30–36 inches. Eastern Idaho (Idaho Falls, Pocatello) sees similar depths. Mountain communities at higher elevations can require 48 inches or more.

For sheds under 200 square feet that don't need a permit, no specific foundation type is required. Concrete blocks, gravel pads, pressure-treated skids, and pier blocks are all acceptable. The shed should be anchored, particularly in areas prone to high winds.

For sheds over 200 square feet, the foundation requirements follow the tiered system most clearly articulated by Meridian: shallow slab for unheated sheds up to 600 square feet, frost-depth footings for heated sheds or those over 600 square feet.

Snow Loads: A Tale of Two Idahos

Idaho's snow load requirements split dramatically between the mild Treasure Valley and the mountain communities.

Treasure Valley snow loads are moderate — approximately 25–30 psf ground snow load for Boise, Meridian, and Nampa. Standard IRC prescriptive roof framing handles these loads without special engineering.

Mountain and northern Idaho is a different story. Elmore County's recreation areas require design for 120 psf ground snow load — four times the Treasure Valley standard — and mandate that plans be engineered by an Idaho State licensed engineer. McCall, Sun Valley, and other resort communities have similarly extreme snow loads. Even Coeur d'Alene and the Panhandle see 40–60 psf.

For homeowners buying pre-built sheds, this means verifying the manufacturer's rated snow load against local requirements. A shed designed for 30 psf in the Treasure Valley may fail structurally in McCall under a heavy snowpack.

Agricultural Exemptions: Idaho's Farm Heritage

Idaho's agricultural exemption is broad and explicitly codified. Under Idaho Code §39-4116, agricultural buildings are exempt from building code requirements entirely. The building must be on land actively devoted to forestry or agricultural pursuits as assessed under the state's agricultural property tax exemption (§63-604), and it must be used for housing farm implements, hay, grain, poultry, livestock, or other agricultural products.

The exemption does not apply to structures used as human habitation, places of employment where agricultural products are processed or packaged, or places used by the public. A location permit may still be required to verify zoning compliance.

This exemption is particularly relevant in Idaho's rural communities and in the suburban-rural interface of the Treasure Valley, where many properties retain agricultural zoning. A genuine farming operation can build substantial agricultural structures without building permits, though setback and zoning rules still apply.

Setbacks, Lot Coverage, and Placement

Zoning requirements for sheds vary across Idaho's cities and counties, but common patterns apply.

Setbacks for accessory structures typically range from 5 to 10 feet from side and rear property lines. Twin Falls requires 10 feet between accessory buildings and other structures. Most cities prohibit sheds in the front yard and require them behind the principal structure.

Lot coverage limits restrict the total building footprint as a percentage of the lot. Typical limits in residential zones are 40–50% of the lot, with accessory structures counted toward the total.

Height limits for accessory structures range from 15 feet (Twin Falls) to taller allowances in rural zones. Most cities limit accessory buildings to the height of the principal structure.

HOA Restrictions

Idaho has seen rapid suburban growth, particularly in the Treasure Valley, and many newer developments in Meridian, Nampa, Eagle, and Star are governed by Homeowners Associations (HOAs). HOA restrictions commonly include matching exterior materials and colors, size limits below the zoning maximum, screening from streets, and architectural committee approval. Some HOAs prohibit sheds entirely.

Idaho's Property Owners' Association Act gives HOAs enforcement powers. Always check your HOA's covenants before building, even if the shed is under 200 square feet and exempt from both building and zoning permits.

Consequences of Building Without a Permit

Building without required permits in Idaho can result in fines, stop-work orders, retroactive permits, and forced removal of non-compliant structures. Violations of building codes and zoning regulations are treated seriously, and the penalties vary by jurisdiction.

Permit fees for sheds in Idaho are modest: typically $50–$200 depending on the city and size. The consequences of building without a permit far exceed the permit cost.

If you're also planning a garage or carport alongside your shed, note that Idaho cities limit total accessory structure coverage on residential lots. Plan all accessory projects together to stay within your zoning allowances.

For an overview of all building permit requirements in Idaho — including decks, fences, pools, and more — see our complete Idaho building permit guide.