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Residential Detached Accessory Building Permit (Shed, Garage, Deck, Pool) in Twin Falls, Idaho

Required for detached accessory structures over 200 square feet (garages, sheds, carports, gazebos, greenhouses, detached decks) and pools greater than 24 inches deep on residential property in Twin Falls. Reviewed against the 2018 IRC and IECC with Idaho amendments.

Verified 2026-07-03 · Source

When you need this permit

  • Building permit required for residential detached accessory buildings over 200 square feet, or any pool greater than 24 inches deep
  • Structure must be sited a minimum of 10 feet from any part of the house (measured to the edge of the house or an existing covered porch/patio post)
  • Structures more than two stories, over 10 feet single-story wall height, or exceeding prescriptive code requirements require plans and calculations engineered and stamped by an Idaho-licensed engineer or architect
  • Plans designed to the 2018 IRC and IECC with Idaho amendments
  • Energy compliance required via prescriptive approach or ResCheck
  • When increasing building square footage on the property by more than 25%, curb, gutter, and sidewalk are required in most zones (deferral available in areas where none exist, via notarized Warranty Deed)
  • Solid-surface driveways required for all garages used for vehicle parking/maneuvering
  • Verified compliance with setbacks, easements, and flood plain status required as part of Planning and Zoning review
  • Fire Department review of fire hydrant locations; additional fire protection may be required if the detached building exceeds 56,000 cubic feet
  • All permits expire 180 days from issuance or the date of the last inspection

Required documents

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Fee schedule

Building Permit Fee — valuation $1 to $500Project value includes total value of work for which the permit is issued (electrical, gas, mechanical, plumbing, equipment, permanent systems, materials and labor), excluding only land value, per COTF Resolution No. 2024-011. City of Twin Falls Residential Detached Accessory Building Application
$22.00
Building Permit Fee — valuation $501 to $2,000City of Twin Falls Master City-Wide Fee Schedule
$22.00 for the first $500, plus $2.75 for each additional $100 or fraction thereof
Building Permit Fee — valuation $2,001 to $25,000City of Twin Falls Master City-Wide Fee Schedule
$63.00 for the first $2,000, plus $12.50 for each additional $1,000 or fraction thereof
Residential Plan Review FeeCity of Twin Falls Master City-Wide Fee Schedule
30% of the building permit fee

Review timeline

Plan reviewTwin Falls’s published plan-review target
10–10 business days

How long did your Residential Detached Accessory Building Permit (Shed, Garage, Deck, Pool) permit actually take in Twin Falls?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Foundation/Footing

    Before concrete pour; required expanded footing dimensions, reinforcement type/size/location, and hold-downs verified per plans

  2. 2

    Framing

    Wall bracing, truss layout, header locations verified; all rough-in inspections for any MEP work must be signed off first

  3. 3

    Final / Certificate of Completion

    Completed structure verified against approved plans; a Certificate of Completion is issued after all inspections pass

See the full Twin Falls inspection guide — scheduling & re-inspection fees →

Tips

  • Detached decks, garages, and sheds use this application (not the Residential Addition applications, which are for structures attached to the main dwelling).
  • A Special Use Permit may be required in certain zones if the accessory building exceeds a certain size — check with City staff.
  • New accessory dwelling units require smoke detectors powered from building wiring, interconnected, with battery backup, per this application's ADU note.
  • Digital plan submittal (PDF saved directly from CAD) is preferred over scans for faster processing; email to bsdpermits@tfid.org.

Frequently asked questions

A building permit is required for any detached accessory structure over 200 square feet, including sheds. Sheds 200 square feet or less do not require a permit under this threshold, per the City of Twin Falls Permit Requirements page and Residential Detached Accessory Building Application.

In Twin Falls, the published Building Permit Fee — valuation $1 to $500 is: $22.00. Additional published fees: Building Permit Fee — valuation $501 to $2,000 — $22.00 for the first $500, plus $2.75 for each additional $100 or fraction thereof; Building Permit Fee — valuation $2,001 to $25,000 — $63.00 for the first $2,000, plus $12.50 for each additional $1,000 or fraction thereof; Residential Plan Review Fee — 30% of the building permit fee. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Twin Falls's published plan-review target for a residential detached accessory building permit (shed, garage, deck, pool) is 10–10 business days.

You'll need: Residential Detached Accessory Building Permit Application; Residential Detached Accessory Building Checklist. See the required-documents checklist on this page for details on each.

Twin Falls requires 3 inspection(s) for a residential detached accessory building permit (shed, garage, deck, pool), in order: Foundation/Footing, Framing, Final / Certificate of Completion. Schedule each through City of Twin Falls Building Safety Department ((208) 735-7238).

Apply through City of Twin Falls Building Safety Department at 203 Main Avenue East, 2nd Floor of City Hall, Twin Falls, ID 83301 (P.O. Box 1907, Twin Falls, ID 83303-1907). Phone: (208) 735-7238, email: bsdpermits@tfid.org. Office hours: Building Safety Department, 2nd Floor of City Hall, 203 Main Avenue East, Twin Falls, ID 83301. Dedicated inspection request lines: Building Inspection (208) 735-7333, Plumbing Inspection (208) 735-7299, Mechanical Inspection (208) 735-7289, Electrical Inspection (208) 735-7235.. Official information: https://www.tfid.org/141/Building-Safety-Department.

Twin Falls, Idaho has adopted: Idaho Building Code Act (Idaho Code Title 39, Chapter 41) makes building code standards a matter of statewide concern; local governments that issue building permits and perform code enforcement must adopt the International Building Code and Idaho Residential Code (Parts I-III and IX) and the Idaho Energy Conservation Code as amended by the Idaho Building Code Board through negotiated rulemaking, and may not adopt subsequent IRC/IECC residential provisions not yet adopted by the Board. Source: Idaho Legislature, Idaho Code Title 39 Chapter 41 (39-4116, Local Government Adoption and Enforcement of Building Codes), https://legislature.idaho.gov/statutesrules/idstat/title39/t39ch41/; 2018 International Building Code (IBC), including accessibility appendices, adopted and incorporated by reference statewide with Idaho amendments; locally administered and enforced by the City of Twin Falls Building Safety Department for commercial construction within city limits. Source: City of Twin Falls Design Criteria: Commercial page and Idaho Building Code Act (Title 39 Ch. 41); 2018 International Residential Code (IRC), Parts I-VI and IX, Appendices A, B and G, with Idaho State amendments, adopted and locally administered by the City of Twin Falls for one- and two-family dwellings and townhouses within city limits. Source: City of Twin Falls Design Criteria: Residential page; 2018 International Energy Conservation Code (IECC), with Idaho State amendments, locally administered by the City of Twin Falls for residential construction. Source: City of Twin Falls Design Criteria: Residential page; 2023 National Electrical Code (NEC), per Idaho Rules and Amendments, locally administered and inspected by the City of Twin Falls Building Safety Department (dedicated Electrical Inspection line). Source: City of Twin Falls Design Criteria: Residential page and Inspections page; 2017 Idaho State Plumbing Code, locally administered and inspected by the City of Twin Falls Building Safety Department (dedicated Plumbing Inspection line). Source: City of Twin Falls Design Criteria: Residential page; City of Twin Falls has assumed local jurisdiction for issuing and inspecting building, electrical, plumbing, and mechanical permits within city limits (dedicated Building, Plumbing, Mechanical, and Electrical inspection phone lines are all City of Twin Falls Building Safety Department lines). The Idaho Division of Occupational and Professional Licenses (DOPL) separately registers/licenses electrical, plumbing, and HVAC contractors statewide (a distinct function from the City's permit issuance and inspection authority); DOPL's own Permits and Inspections program applies only in jurisdictions that have NOT assumed local authority, and DOPL confirms permit/inspection jurisdiction 'varies widely' by city/county assumption of authority. Source: DOPL Permits and Inspections page, https://dopl.idaho.gov/plb/plb-permits-and-inspections/, cross-checked against City of Twin Falls Inspections page listing City-run Building/Plumbing/Mechanical/Electrical inspection lines. Local amendments apply — see the Twin Falls overview page for the full list.

Sources & verification

Verified against official sources. Last reviewed 2026-07-03.

Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Twin Falls building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.