Home / Idaho Permits / Twin Falls County

Building Permits in Twin Falls County, Idaho

County jurisdiction

Verified August 2026

See Twin Falls County's fees, required documents and inspection sequence: free for 14 days, no card required.Sign in Start free trial

Adopted Construction Codes

These are the state-level code editions for Idaho. They apply in Twin Falls Countyunless a verified local adoption or amendment is noted — in local-adoption states, confirm the city or county's own code editions with the building department.

Code	Edition	Adoption
IBC — International Building Code	2018 IBC — the 2018 International Building Code, published by the International Code Council, adopted by the Idaho Building Code Board at IDAPA 24.39.30.600.01 ("Rules of Building Safety", Section 600). ADOPTING WORDS VERBATIM: "Pursuant to Sections 39-4109 and 39-4109A, Idaho Code, the Board adopts the following international codes with identified amendments:" followed by "01. International Building Code. The 2018 Edition, including appendices pertaining to building accessibility, with the following amendments:". NOT 2024 AND NOT 2021 WHOLESALE. * BUT IDAHO IS A SPLICED-EDITION STATE AND THIS IS THE FINDING: IDAPA 24.39.30.600.02 SEPARATELY ADOPTS NAMED PROVISIONS OF THE 2021 IBC — "The following provisions of the 2021 Edition related to mass timber construction:" — i.e. four 2021 definitions (MASS TIMBER; NONCOMBUSTIBLE PROTECTION (FOR MASS TIMBER); SECONDARY STRUCTURAL MEMBERS; WALL, LOAD BEARING), a long list of 2021 sections (403.3.2, 508.4.4.1, 509.4.1.1, 602.4-602.4.3.6, 703.6, 703.7, 704.4, 722.7-722.7.2.2, 1705.5.3, 1705.20, 2304.10.1, 3313.1-3313.3.3, 3313.5, 3314.1), eight 2021 tables (504.3, 504.4, 506.2, 601, 705.5, 722.7.1(1), 722.7.1(2), 1705.5.3) and two referenced standards (ANSI/APA PRG 320-2019, ASTM D3498-03(2011)). AN IDAHO MASS-TIMBER BUILDING IS DESIGNED UNDER 2021 IBC TEXT INSIDE A 2018 IBC CODE. NO SINGLE EDITION LABEL IS TRUE OF IDAHO.** Also adopted by amendment 600.01(d): a new Section 602.1.2 admitting construction types IV-A, IV-B and IV-C, which do not exist in the 2018 IBC — the seam that makes the 2021 splice work. Prior value was the bare string "2018" with a 34-character citation, no quoted instrument, no amendments and a NULL effective_date while carrying verified_at.	IDAPA 24.39.30.600.01 and .600.02 — Idaho Building Code Board, "Rules of Building Safety", Section 600. ADOPTING SENTENCE VERBATIM: "Pursuant to Sections 39-4109 and 39-4109A, Idaho Code, the Board adopts the following international codes with identified amendments:". LEGAL AUTHORITY LINE AS PRINTED: "The rules are promulgated pursuant to Sections 33-356, 39-4107, 39-4109, 39-4112, 39-4113, 39-9701, Idaho Code." Rule text dated (7-1-24) throughout, which is the effective_date recorded here. Statutory backstop: Idaho Code 39-4109 and 39-4109A. Read first-hand from the State's own rules host, 2026-09-20. · source ↗
IEBC — International Existing Building Code	2018 IEBC — the 2018 International Existing Building Code, published by the International Code Council, adopted by the Idaho Building Code Board at IDAPA 24.39.30.600.04. THE WHOLE SUBSECTION, VERBATIM: "04. International Existing Building Code. 2018 Edition." THAT IS THE ENTIRE ADOPTION — NO CHAPTER LIST, NO APPENDICES NAMED, AND NO AMENDMENTS AT ALL, WHICH MAKES IT THE ONLY UNAMENDED CODE IN IDAHO'S BUILDING-SAFETY RULE: every other subsection of Section 600 (IBC, IRC, IECC commercial, IECC residential) carries "with the following amendments:" and a lettered list, and this one does not. NOT 2024, NOT 2021. Prior value was the bare string "2018" with the 14-character citation "IDAPA 24.39.30", no instrument text, no effective date and a source_url pointing at a DOPL summary PDF ("2025-Updated-Idaho-Adopted-Codes.pdf") rather than at the rule.	IDAPA 24.39.30.600.04 — Idaho Building Code Board, "Rules of Building Safety", Section 600, subsection 04. ADOPTING SENTENCE VERBATIM: "Pursuant to Sections 39-4109 and 39-4109A, Idaho Code, the Board adopts the following international codes with identified amendments:"; the subsection itself reads in full: "04. International Existing Building Code. 2018 Edition." LEGAL AUTHORITY AS PRINTED: "The rules are promulgated pursuant to Sections 33-356, 39-4107, 39-4109, 39-4112, 39-4113, 39-9701, Idaho Code." Rule text dated (7-1-24). Read first-hand from the State's own rules host, 2026-09-20; the prior citation named only the chapter and the prior source_url was a DOPL summary hand-out, not the instrument. · source ↗
IECC — International Energy Conservation Code	2018 IECC — the 2018 International Energy Conservation Code, adopted by the Idaho Building Code Board at IDAPA 24.39.30 ("Rules of Building Safety"), Section 600. *** IDAHO ADOPTS THE COMMERCIAL AND RESIDENTIAL PROVISIONS AS TWO SEPARATE ADOPTIONS WITH SEPARATE AMENDMENT SETS, BOTH ON THE 2018 EDITION. Subsection 05 verbatim: "International Energy Conservation Code - Commercial Provisions. The 2018 Edition with the following amendments:". Subsection 06 verbatim: "International Energy Conservation Code - Residential Provisions. The 2018 Edition with the following amendments:". Introductory adopting sentence verbatim: "Pursuant to Sections 39-4109 and 39-4109A, Idaho Code, the Board adopts the following international codes with identified amendments:". NOT 2021 AND NOT 2024 — neither is adopted in Idaho. Prior value was the bare string "2018" with no instrument, no commercial/residential split, no amendment count, no effective date and a secondary source_url (a DOPL summary PDF).	IDAPA 24.39.30.600.05 (commercial) and .600.06 (residential) — Idaho Building Code Board, "Rules of Building Safety," Section 600. Adopting sentence verbatim: "Pursuant to Sections 39-4109 and 39-4109A, Idaho Code, the Board adopts the following international codes with identified amendments:". Legal authority: Sections 39-4109 and 39-4109A, Idaho Code. Rule text dated (7-1-24). Companion Idaho code adoptions sit under separate boards: IDAPA 24.39.70 (HVAC Board, 2018 IMC), IDAPA 24.39.20 (Plumbing Board, 2015 UPC), IDAPA 24.39.10 (Electrical Board, 2023 NEC), Idaho Code 41-253 (State Fire Marshal, 2018 IFC). · source ↗
IFC —	2018 IFC — the 2018 International Fire Code, published by the International Code Council, in effect statewide in Idaho since 2021-01-01. READ THE NEXT PARAGRAPH BEFORE TOUCHING THIS FIELD: IDAHO IS A ROLLING-ADOPTION STATE AND NEITHER ITS STATUTE NOR ITS RULE NAMES 2018. Idaho Code 41-253(1) adopts, verbatim, 'the "International Fire Code," 2000 edition, with appendices thereto, published by the International Code Council, Inc. and such later editions as may be so published and adopted by the state fire marshal, as the minimum standards for the protection of life and property from fire and explosions in the state of Idaho.' IDAPA 18.08.01 Section 001 then says, verbatim, 'Pursuant to the authority provided by Section 41-253, Idaho Code, the State Fire Marshal adopts the International Fire Code (IFC) as the minimum standard for the protection of life and property from fire and explosion in the state of Idaho' — WITH NO EDITION YEAR IN THE RULE TEXT EITHER. SO THE OPERATIVE EDITION IS FIXED BY THE STATE FIRE MARSHAL'S ACT OF ADOPTION, NOT BY THE FOUR CORNERS OF EITHER INSTRUMENT. THE 2018 EDITION AND ITS 2021-01-01 EFFECTIVE DATE COME FROM THE FIRE MARSHAL'S OWN PUBLISHED RULEMAKING IN THE IDAHO ADMINISTRATIVE BULLETIN (Docket 18-0801-2001), WHICH STATES: "the 2018 fire code (IFC) that will go into effect on January 1, 2021", AND IS CORROBORATED BY THE STATE FIRE MARSHAL'S OWN CODES-AND-STANDARDS PAGE, WHICH POINTS AT THE 2018 IFC. DO NOT RECORD 2021 OR 2024 — NEITHER IS IN FORCE IN IDAHO. AND DO NOT "CORRECT" THIS TO 2000 ON THE STRENGTH OF THE STATUTE: 2000 IS THE FLOOR THE LEGISLATURE SET IN 1970-VINTAGE LANGUAGE, NOT THE LIVE EDITION.	IDAHO CODE 41-253 ("Statement of purpose — Adoption of international fire code"), Title 41 ch. 2, together with IDAPA 18.08.01 ("Adoption of the International Fire Code"), Idaho Department of Insurance / STATE FIRE MARSHAL, legal authority line quoted verbatim: "Title 41, Chapter 2, Idaho Code. (7-1-24)". Operative edition established by Idaho Administrative Bulletin DOCKET NO. 18-0801-2001 (published notice of intent, Vol. 20-6, June 3 2020). Statute history: [(41-253) 39-3501 added 1970, ch. 190; am. and redesig. 1982, ch. 120; am. 2002, ch. 86; am. 2008, ch. 402; am. 2010, ch. 219, sec. 1, p. 492]. · source ↗
IFGC — International Fuel Gas Code	2018 IFGC — the 2018 International Fuel Gas Code, published by the International Code Council, INCLUDING APPENDICES A, B, C AND D, adopted NOT by the Building Code Board but by the IDAHO HEATING, VENTILATION, AND AIR CONDITIONING BOARD at IDAPA 24.39.70.600.02 as part of the "Idaho Mechanical Code". ADOPTING WORDS VERBATIM: "Pursuant to Section 54-5001, Idaho Code, the Board adopts, as the Idaho Mechanical Code, the following international codes with identified amendments:" followed by "02. International Fuel Gas Code. The 2018 Edition, including appendices A, B, C, and D, with the following amendments:". NOT 2024, NOT 2021. * THE PRIOR CITATION ON THIS ROW WAS SIMPLY WRONG AND POINTED AT A BODY THAT ADOPTS NO CODE — SEE adoption_citation. * COMPANION RESIDENTIAL PATH: THE SAME HVAC BOARD ALSO ADOPTS, AT 24.39.70.600.03, "The 2018 Edition, Part V (Mechanical) and Part VI (Fuel Gas) and appendices A, B, C, and D" OF THE IRC — SO RESIDENTIAL FUEL GAS IN IDAHO IS IRC PART VI UNDER THE HVAC BOARD, NOT THE IFGC, AND NOT UNDER THE BUILDING CODE BOARD WHOSE IRC ADOPTION (24.39.30.600.03) TAKES ONLY PARTS I, II, III AND IX. Prior value was the bare string "2018" with the 14-character citation "IDAPA 24.39.50", no instrument text, no effective date and a DOPL summary-PDF source_url.	IDAPA 24.39.70.600.02 — Idaho Heating, Ventilation, and Air Conditioning Board, "Rules Governing Heating, Ventilation, and Air Conditioning Systems", Section 600 (IDAHO MECHANICAL CODE), subsection 02. ADOPTING SENTENCE VERBATIM: "Pursuant to Section 54-5001, Idaho Code, the Board adopts, as the Idaho Mechanical Code, the following international codes with identified amendments:". Rule text dated (3-28-23), which is the effective_date recorded here (the prior row carried NULL). *** THE CITATION THIS ROW PREVIOUSLY CARRIED, "IDAPA 24.39.50", IS WRONG AND I READ THAT CHAPTER TO CONFIRM IT: IDAPA 24.39.50 IS THE "Rules of the Public Works Contractors License Board", whose authority line reads verbatim "This chapter is adopted pursuant to Sections 54-1907, 67-2604, 67-2614, 67-9409, and 67-9406 Idaho Code, as amended. (7-1-24)", AND IT ADOPTS NO MODEL CODE OF ANY KIND — IT IS A CONTRACTOR LICENSING CHAPTER. A READER SENT THERE FOR IDAHO'S FUEL GAS LAW FINDS NOTHING AND HAS NO WAY TO KNOW WHY. Read first-hand from the State's own rules host, 2026-09-20. · source ↗
IMC — International Mechanical Code	2018	IDAPA 24.39.70.600.01 — Idaho Heating, Ventilation, and Air Conditioning Board, "Rules Governing Heating, Ventilation, and Air Conditioning Systems," Section 600 (IDAHO MECHANICAL CODE), subsection 01. Adopting sentence verbatim: "Pursuant to Section 54-5001, Idaho Code, the Board adopts, as the Idaho Mechanical Code, the following international codes with identified amendments: ... 01. International Mechanical Code. The 2018 Edition, including appendix A, with the following amendments:". Legal authority stated by the chapter: "Sections 54-5001, 54-5004, 54-5005, 54-5006, 54-5007, 54-5010, 54-5016, 67-2604, 67-2614, 67-9406 and 67-9409, Idaho Code." Rule text dated (3-28-23). · source ↗
IPC — International Plumbing Code	NOT ADOPTED — AND STATUTORILY BARRED, WHICH IS STRONGER THAN ANY OTHER IPC NEGATIVE IN THIS TABLE. Idaho adopts NO edition of the International Plumbing Code, at state or local level, and cannot lawfully do so. The Idaho State Plumbing Code (ISPC) is the 2015 UNIFORM PLUMBING CODE (IAPMO), including Appendices A, B, C, D, E, G, I, J, K and L, adopted by the Idaho Plumbing Board at IDAPA 24.39.20.600 with 50 itemized Idaho amendments. ADOPTING SENTENCE READ AND QUOTED VERBATIM FROM THE RULE: "Pursuant to Section 54-2601, Idaho Code, the Board adopts, as the Idaho State Plumbing Code (ISPC), the 2015 Uniform Plumbing Code, including Appendices A, B, C, D, E, G, I, J, K and L, with the following amendments:". THE PHRASES "INTERNATIONAL PLUMBING CODE" AND "IPC" DO NOT APPEAR ANYWHERE IN IDAPA 24.39.20 — CHECKED THIS RUN. Nor do they appear in Idaho Code 54-2601, the authorizing statute, which names one publisher by name: "the uniform plumbing code published by the international association of plumbing and mechanical officials". DO NOT RECORD AN IPC EDITION FOR IDAHO ON ANY DEFAULT, SUMMARY OR SIBLING-ROW THEORY.	IDAHO CODE 54-2601 (Title 54, Ch. 26 — "Declaration of policy and purpose of act — Idaho state plumbing code"), read in full this run, together with IDAPA 24.39.20.600 (Idaho Plumbing Board, "Rules Governing Plumbing," Section 600), rule text dated (3-28-23). These are the instruments that make the IPC unadoptable in Idaho and put the 2015 UPC in its place. Rule authority line quoted verbatim: "The rules are promulgated pursuant to Section 54-2601, 54-2605, 54-2606, 54-2607, 54-2617, 54-2624, 67-2604, 67-2614, 67-9406 and 67-9409, Idaho Code." Statute history: [(54-2601) 39-2701, added 1957, ch. 214, sec. 1, p. 454; am. 1963, ch. 138; am. 1975, ch. 120; am. and redesig. 1984, ch. 123; am. 2012, ch. 53; am. 2015, ch. 141; am. 2024, ch. 54, sec. 2, p. 269] — NOTE THE 2024 AMENDMENT, THE MOST RECENT LEGISLATIVE TOUCH, WHICH DID NOT INTRODUCE THE IPC. · source ↗
IRC — International Residential Code	2018 IRC — the 2018 International Residential Code, published by the International Code Council, adopted by the Idaho Building Code Board at IDAPA 24.39.30.600.03. ADOPTING WORDS VERBATIM: "03. International Residential Code, 2018 Edition. Parts I, II, III, and IX of the 2018 Edition for one (1)- and two (2)- family dwellings, with the following amendments:". NOT 2024, NOT 2021. * THE ADOPTION IS PARTIAL BY PART, AND THE MISSING PARTS ARE NOT MISSING FROM IDAHO LAW — THEY ARE ADOPTED BY OTHER BOARDS, WHICH IS THE FINDING. The Building Code Board takes Parts I (Administration), II (Definitions), III (Building Planning and Construction) and IX (Referenced Standards) only. THE OTHER FIVE PARTS ARE EACH PICKED UP ELSEWHERE: Part IV (Energy) by the same board at 600.06 as the 2018 IECC Residential Provisions; PARTS V (MECHANICAL) AND VI (FUEL GAS) BY THE HVAC BOARD AT IDAPA 24.39.70.600.03, VERBATIM: "The 2018 Edition, Part V (Mechanical) and Part VI (Fuel Gas) and appendices A, B, C, and D, for one (1)- and two (2)- family dwellings with the following amendments:"; Part VII (Plumbing) displaced by the Plumbing Board's 2015 UPC at IDAPA 24.39.20.600; Part VIII (Electrical) displaced by the Electrical Board's amended 2023 NEC at IDAPA 24.39.10.600. ALL NINE PARTS OF THE IRC ARE IN FORCE IN IDAHO AND NO SINGLE INSTRUMENT, BOARD OR DOCUMENT CONTAINS THEM. THE PART NAMES ABOVE ARE THE STANDARD ICC PART TITLES AND WERE NOT QUOTED FROM THE IDAHO RULES, WHICH GIVE ONLY "Part V (Mechanical)" AND "Part VI (Fuel Gas)" BY NAME AND THE REST BY NUMBER.** Prior value was the bare string "2018" with a 56-character citation, no quoted instrument, no amendments and a NULL effective_date while carrying verified_at.	IDAPA 24.39.30.600.03 — Idaho Building Code Board, "Rules of Building Safety", Section 600, subsection 03. ADOPTING SENTENCE VERBATIM: "Pursuant to Sections 39-4109 and 39-4109A, Idaho Code, the Board adopts the following international codes with identified amendments:"; subsection verbatim: "Parts I, II, III, and IX of the 2018 Edition for one (1)- and two (2)- family dwellings, with the following amendments:". LEGAL AUTHORITY AS PRINTED: "The rules are promulgated pursuant to Sections 33-356, 39-4107, 39-4109, 39-4112, 39-4113, 39-9701, Idaho Code." Rule text dated (7-1-24). Companion parts sit under other boards: IDAPA 24.39.70.600.03 (HVAC Board, IRC Parts V and VI), IDAPA 24.39.20.600 (Plumbing Board, 2015 UPC), IDAPA 24.39.10.600 (Electrical Board, amended 2023 NEC). Read first-hand from the State's own rules host, 2026-09-20. · source ↗
NEC — National Electrical Code (NFPA 70)	2023 NEC — NFPA 70, National Electrical Code, 2023 edition, AS AMENDED IN 34 PLACES, adopted by the Idaho Electrical Board at IDAPA 24.39.10 Section 600 ("IDAHO ELECTRICAL CODE"). ADOPTING WORDS VERBATIM, THE WHOLE OPENING SENTENCE: "Under the provisions of Section 54-1001, Idaho Code, the National Electrical Code, 2023 Edition, (herein NEC) is amended as follows:". *** NOTE THE GRAMMAR, IT IS THE POINT: IDAHO DOES NOT SAY IT "ADOPTS AND INCORPORATES BY REFERENCE" — IT SAYS THE NEC "IS AMENDED AS FOLLOWS" AND THEN NAMES THE PRODUCT "THE IDAHO ELECTRICAL CODE". THE SECTION HEADING IS THE ADOPTION. A SEARCH FOR THE USUAL "adopted and incorporated by reference" FORMULA DOES NOT FIND IDAHO'S ELECTRICAL ADOPTION AT ALL — THE SAME CLASS OF TRAP AS SOUTH DAKOTA'S NEC ADOPTION HIDING IN A DEFINITIONS SUBDIVISION (RUN 1606). s.600 ALSO STATES: "A copy of the 2023 National Electrical Code is available at the offices of the Division of Occupational and Professional Licenses." — i.e. the base text is not state-published, it is available for inspection. Rule text dated (4-4-25). Prior value was the bare string "2023" with a 102-character citation, no quoted instrument, no amendments and a NULL effective_date while carrying verified_at.	IDAPA 24.39.10.600 ("IDAHO ELECTRICAL CODE"), Idaho Electrical Board, Division of Occupational and Professional Licenses. OPENING SENTENCE VERBATIM: "Under the provisions of Section 54-1001, Idaho Code, the National Electrical Code, 2023 Edition, (herein NEC) is amended as follows:". STATUTORY AUTHORITY AS PRINTED: "Under the provisions of Section 54-1001, Idaho Code"; chapter authority Idaho Code tit. 54 ch. 10. Rule text dated (4-4-25) throughout, which is the effective_date recorded here (the prior row carried NULL). NOTE ON THE SOURCE URL: adminrules.idaho.gov/rules/current/24/243910.pdf 302-REDIRECTS TO files.dfm.idaho.gov; the files.dfm host is recorded here as the one that actually serves the document. Read first-hand, 2026-09-20. · source ↗
UPC —	2015	IDAPA 24.39.20.600 (Idaho Plumbing Board, Rules Governing Plumbing), adopting the 2015 Uniform Plumbing Code incl. Appendices A, B, C, D, E, G, I, J, K, L, pursuant to Idaho Code 54-2601; rule text dated 3-28-23 · source ↗

Permit Requirements

Statewide baseline under the codes as adopted by Idaho. Local amendments and fee schedules for Twin Falls County are being verified — use the building department contacts to confirm before you build.

building permit