Jefferson County - Planning, Zoning & Building

Jefferson County, Idaho

county

210 Courthouse Way, Suite 170, Rigby, ID 83442

Required

Required

ESTABLISH WHOSE PERMIT IT IS BEFORE ANYTHING ELSE. The Department states that its "building permit services extend to also serve the cities of Lewisville, Menan, and Rigby", and its published guidance adds that properties in the City of Mud Lake use Jefferson County permits while the County "does not handle permits for" the City of Ririe or the City of Roberts. The same guidance is blunt about how to work it out: jurisdiction "is not based on your mailing or physical address" but on whether the property sits in unincorporated Jefferson County or inside an incorporated city. HOW LONG IT TAKES AND WHAT IT COSTS. The County's Building Permit Process document, dated June 26, 2025, sets out eleven steps from pre-application to certificate of occupancy and states that the review "takes approximately 15 business days on a non-commercial building permit application and approximately 20 business for a commercial building permit application." The Plan Review Fee, GIS Fee and Technology Fee must be paid before further reviews are conducted. The 2026 Jefferson County Fee Schedule, Exhibit A, charges building permits on total valuation: $26.46 for a valuation of $1 to $500; "$26.46 for the first $500, plus $3.30 for each additional $100 or fraction thereof to and including $2000" from $501 to $2,000; and "$75.96 for the first $2,000; plus $12.13 for each additional $1,000 or fraction thereof to and including $40,000" from $2,001 to $40,000, which is the bracket most residential reroofs fall in. On top of that, "GIS/Mapping Review for all file types" adds $30.00 to each application, an inspection fee and a re-inspection fee are each $90.00, and an appeal is $500.00. Two penalty lines are worth knowing: "Failure to obtain building/moving permit" costs "2X the permit fee, plus apply for permit and pay applicable fee", and "Failure to Request Inspection (performing work without having passed the inspection)" costs 25% of the permit fee. HOW TO APPLY. Applications go through the County's Cityworks public portal, and the County warns that "You must use Google Chrome or Mozilla Firefox to access the public portal and apply for building permits. Edge or Safari are not suppported." Once issued, "The permit sign must be visibly posted on the property." THE INSPECTION SEQUENCE, AS THE COUNTY PUBLISHES IT, in order: layout; footing, which must occur before concrete is poured; foundation, likewise; sheathing, with the note that the building cannot be wrapped; all state rough-in inspections for electrical, plumbing and HVAC; framing; insulation; drywall, with the note that seams cannot be taped or mudded; all state final inspections; a health department final if applicable; and the building department final. The County adds that "The above inspections are the basic inspections on a building permit. Your specific building permit may not require all of these or there may be additional inspections which are required", so confirm the sequence for the permit you actually hold. Where the property is inside a city the County serves, the certificate of occupancy or completion is forwarded to that city to issue. THE ELECTRICAL, PLUMBING AND HVAC LAYERS ARE THE STATE'S. Jefferson County Code 104-24 deletes International Building Code sections 101.4.1 gas, 101.4.2 mechanical and 101.4.3 plumbing, and all electrical, plumbing and HVAC requirements of residential code chapters 12 through 41, "thus solely regulated under the state division of building safety". Section 104-2 also makes a building permit a prerequisite to an electrical power connection.

THE 2018 EDITIONS, ADOPTED BY ORDINANCE AND CODIFIED. Jefferson County Code section 104-23, "Adoption of the 2018 International Building Codes", adopts "The 2018 edition of the International Building Code, promulgated by the International Code Council, and amendments adopted herewith together with standards incorporated into the International Building Code by reference, including but not limited to the 2018 edition of the International Residential Code promulgated by the International Code Council save and except such portions of the above mentioned codes as a deleted, modified, or amended by provisions of this article", and does so "for regulating the erection, construction, enlargement, alteration, repair, moving, removal, demolition, conversion, occupancy, equipment, use, height, area, and maintenance of all buildings or structures in Jefferson County; for issuance of permits and collection of fees therefore". The codified section is attributed to Ordinance No. 2022-12, section 1, adopted October 3, 2022. TWO COUNTY SOURCES NAME DIFFERENT ADOPTING ORDINANCES, AND BOTH ARE REPORTED. The County's own frequently asked questions page answers "What building code has Jefferson County adopted?" with: "Jefferson County adopted the 2018 International Building Code and International Residential Code on March 7, 2022", and links an Ordinance 2022-02. The codified Chapter 104 attributes every one of its building-code sections to Ordinance No. 2022-12 of October 3, 2022. The edition is the same either way; only the instrument and the date differ. The FAQ's link to Ordinance 2022-02 does not resolve - it returns the County website's not-found page - so that ordinance could not be read here. WHERE THE CODE IS PUBLISHED. Chapter 104 was read from two copies that agree: the County's own PDF of Part III, Land Development Ordinances, and the Municode codification of the Jefferson County Code, which states that it is codified through Ordinance No. 2024-06, enacted April 22, 2024. Note that the County's ordinances page now also links a codification on a different vendor's platform, so check for a supplement more recent than April 2024 before relying on a fine point. WHAT STATE LAW REQUIRES. IDAPA 24.39.30.600.03 adopts the "International Residential Code, 2018 Edition ... Parts I, II, III, and IX of the 2018 Edition for one (1)- and two (2)- family dwellings", effective July 1, 2024, with a list of state amendments; Idaho Code 39-4116(2) requires a local government that issues building permits and performs building code enforcement to adopt those codes by ordinance and bars it from adopting a later residential code edition the Idaho Building Code Board has not adopted. Roofing sits in Part III and is inside the Idaho residential code. Idaho Code 39-4116(6): "Permits shall be governed by the laws in effect at the time the permit application is received."

Required — Jefferson County Code Chapter 104, the County's building code chapter and its complete list of deletions, modifications and amendments, was read in full and does not touch Chapter 9, Roof Assemblies; the word drip does not appear in it. IDAPA 24.39.30.600.03, the State of Idaho's own amendment list, does not touch Chapter 9 either. The base 2018 International Residential Code drip-edge requirement for asphalt shingle roofs, Section R905.2.8.5, therefore applies unmodified in Jefferson County and in the cities the County permits for. Confirm the flashing detail and the fastener spacing against the shingle manufacturer's printed instructions as well, which the code makes binding. About drip edge

Not required — No impact-resistance mandate applies in Jefferson County. Chapter 104 of the Jefferson County Code, Buildings and Building Regulations, was read in full - both articles, all sections - and contains no reference to UL 2218, to a Class 4 or Class IV impact rating, or to FM 4473, and no amendment to Chapter 9, Roof Assemblies. The whole of Part III of the County Code, its land development ordinances, was searched for the same four terms and contains none of them. IDAPA 24.39.30.600.03, the State of Idaho's own amendment list to the International Residential Code, read in full, contains no such reference either. So neither the County's nor the State's adopted code imposes an impact-resistant roof covering requirement. Do not confuse this with the fire and wind ratings that also appear in roofing work: an impact rating is UL 2218, a fire classification is Class A, B or C under ASTM E108 or UL 790, and a wind rating is ASTM D3161 or D7158. An insurance discount for impact-rated shingles, where a carrier offers one, is a matter between the homeowner and the insurer and is not a code requirement.

JEFFERSON COUNTY SETS NO SIZE, AREA, DOLLAR OR TEAR-OFF-VERSUS-OVERLAY THRESHOLD FOR A REROOF, AND ITS PUBLISHED EXEMPTION LIST HAS NO ROOFING ITEM. The County publishes a handout headed "Structures Requiring Building Permits", dated June 27, 2025, which opens: "ICC Building Codes Require: - Owner or authorized agent intending to construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building or structure. - Install, enlarge, alter, repair, remove, convert, or replace any electrical, gas, mechanical, or plumbing system regulated by the code. - Must obtain a permit from the building official." A reroof is a repair or alteration of a building, so it is inside the first line. The County's adopting section says the same from the other side: Jefferson County Code 104-23 adopts the codes "for regulating the erection, construction, enlargement, alteration, repair" of all buildings in the County "and for issuance of permits". THE EXEMPTION LIST, READ IN FULL. That same handout prints the County's residential exemption list in eleven items: one-story detached accessory structures not over 200 square feet; fences not over 7 feet high; retaining walls not over 4 feet unless supporting a surcharge, and water tanks on grade at or below 5,000 gallons with a height-to-width ratio at or below 2:1; sidewalks and driveways not more than 30 inches above adjacent grade and not over a basement or story below; "Painting, papering, tiling, carpeting, cabinets, counter tops, and similar finish work"; prefabricated swimming pools not greater than four feet deep; swings and playground equipment; window awnings supported by an exterior wall that do not project more than 54 inches and need no additional support; decks not exceeding 200 square feet that are not more than 30 inches above grade, not attached to a dwelling and not serving the required exit door; and flag poles. Roofing appears nowhere in it. A separate commercial list follows and likewise contains no roofing item. The handout also warns that "Structures less than 200 sq. ft., which are listed below as not requiring a building permit application, do require a Zoning Certificate." THE ONLY OTHER EXEMPTION IN THE CHAPTER IS AGRICULTURAL. Jefferson County Code 104-26: "Agricultural buildings are exempt from building codes adopted herein when county planning, zoning, and building department have verified that such structure qualifies for the agriculture exemption under state law, but shall remain subject to placement requirements established by county zoning regulations." Section 104-1 sets out the test in detail, including that the parcel must be "an agricultural unit of land of five acres or more". THERE IS NO REROOF APPLICATION TYPE ON THE COUNTY'S PORTAL, AND THAT IS WORTH A PHONE CALL BEFORE YOU FILE. The County's guidance document listing every permit category and application type - commercial, manufactured or mobile home, detached accessory building, basement finish or residential remodel, accessory dwelling unit, single family dwelling, non-commercial new addition, agricultural exempt, solar array and zoning certificate - names no reroof or roofing-and-siding type. Ask the Department which application type a reroof is filed under rather than guessing on the portal. THE STATE ADDS NO ROOFING EXEMPTION EITHER, and do not rely on the hundred-square-foot roof repair figure that appears in the Idaho state building code rules. It sits inside the definition of "Minor Alteration", which that rule says "is used for the purpose of administering annual permits" - a blanket permit issued to state agencies for work on buildings they already own or operate. It is not a permit exemption for a homeowner or a roofing contractor anywhere in Idaho.

THE COUNTY REPLACED THE MODEL TABLE WITH ONE SENTENCE, AND IT PRINTS NO WIND BASIS. Jefferson County Code section 104-24(b)(2)a: "Table 301.2(1) shall be amended to read as follows: Live Snow Load ≥35 PSF, ground snow load ≥45 PSF, wind speed - 90 MPH, seismic design category - D-1, weathering - severe, frost line depth - 30", termite - slight/moderate, winter design temp - -4 degrees, flood hazards - FIRM. Jefferson County has a maximum building height restriction. See chapter 112 Zoning." THE TABLE DOES NOT SAY WHETHER 90 MPH IS A FASTEST-MILE, A NOMINAL THREE-SECOND-GUST OR AN ULTIMATE DESIGN SPEED, and those are different measurement bases for the same loading rather than different loadings. A design method, a shingle wind-rating listing or a product approval written for one basis gives the wrong answer if it is fed a number from another, so no basis is supplied here and no conversion is made. Ask the Building Official which basis the County plan-reviews to before selecting a wind-rated assembly or an enhanced fastening pattern. NOTE THAT THE TWO SNOW FIGURES ARE MINIMUMS, NOT VALUES. The County states them with a greater-than-or-equal sign, so a site may carry more, and the number to design to should be established with the Department for the address rather than taken from the sentence. ONE STATE FACT THAT SITS BESIDE THIS AND IS A WIND FACT. The State of Idaho deletes the model code's wind-borne debris opening-protection section statewide: IDAPA 24.39.30.600.03(d) reads "Section R301.2.1.2 Protection of Openings. Delete." That is an opening provision for windows and doors rather than a roofing one, and under Idaho Code 39-4116(4)(b) a local jurisdiction may not re-adopt a provision the Idaho Building Code Board has expressly rejected.

NEITHER JEFFERSON COUNTY NOR THE STATE OF IDAHO MODIFIES THE MODEL RULE. Jefferson County Code Chapter 104, Buildings and Building Regulations, was read in full - both articles and all of its sections, 104-1, 104-2, and 104-23 through 104-30 - from the County's own published copy of Part III of its Code and from the Municode codification, which agree. Its complete list of deletions, modifications and amendments is at section 104-24: for the building code, the deletion of sections 101.4.1, 101.4.2 and 101.4.3 and of section 109.3, the deletion of appendices A, F, K, L, M and N, and an amendment to section 1403.2 on water-resistive barriers; for the residential code, the deletion of all electrical, plumbing and HVAC requirements of chapters 12 through 41, the deletion of appendices A, B, C, D, F, G, H, I, K, N, O and P, the deletion of section R313, and a replacement Table 301.2(1). Not one of them touches Chapter 9, Roof Assemblies, and the chapter contains no recover, overlay or tear-off rule and no roofing provision of any kind. IDAPA 24.39.30.600.03, the Idaho Building Code Board's own list of amendments to the 2018 International Residential Code, seventeen items, contains no Chapter 9 amendment either. So the base 2018 International Residential Code recover-versus-replacement rule applies here unmodified. Base-code rule, 2018 IRC Section R908.3.1.1, Roof recover not allowed: a roof recover is not permitted where the existing roof or roof covering is water soaked or has deteriorated to the point that it is not adequate as a base for additional roofing; where the existing roof covering is slate, clay, cement or asbestos-cement tile; or where the existing roof has two or more applications of any type of roof covering. One existing layer may be recovered; a second forces a full tear-off. A LOCAL AMENDMENT WOULD BE UNUSUALLY VISIBLE IF ONE EXISTED. Idaho Code 39-4116(4)(d) lets a county amend this part of the residential code only by ordinance, on a recorded finding that "good cause" for building or life safety exists and that the amendment is "reasonably necessary", after a public hearing noticed in the official newspaper with at least thirty days' written notice to the local chapters of the industry bodies listed in Idaho Code 39-4109(5). Jefferson County has made no such amendment.

NO LOCAL ROOF-DECK RULE, AND THE ONE AMENDMENT THAT LOOKS LIKE ONE IS A WALL RULE. Jefferson County Code Chapter 104 was read in full and contains no amendment to Chapter 8, Roof-Ceiling Construction, which carries the residential code's roof sheathing provisions, and none to Chapter 9, Roof Assemblies; the chapter contains no occurrence of the word sheathing. IDAPA 24.39.30.600.03, the State of Idaho's own amendment list, leaves both chapters alone as well. So the base 2018 International Residential Code roof sheathing and decking requirements apply unmodified, along with the shingle manufacturer's printed installation instructions, which the code makes binding. THE AMENDMENT THAT IS NOT ABOUT YOUR ROOF DECK. Section 104-24(a)(2)a provides that International Building Code "Section 1403.2 water-resistive barriers shall be amended as to leave installation at the sole discretion of the builder and such installation will not be enforced by the county building department." That is a commercial-code provision about the water-resistive barrier behind an exterior WALL covering. It is not about roof underlayment, roof sheathing or the roof deck, and it does not touch the residential code at all. Do not carry it across to a roof. THE COUNTY DOES INSPECT THE DECK AS ITS OWN STAGE. The County's published building permit process lists "Sheathing Inspection (building cannot be wrapped)" as the fourth required inspection, after layout, footing and foundation. On a job where the deck is opened up, expect it to be looked at before it is covered. SNOW IS WHAT DECIDES A DECK HERE. The County's replacement Table 301.2(1) at section 104-24(b)(2)a states a live snow load and a ground snow load as minimums rather than fixed figures - see wind design criteria below for the table as printed - so establish the design loads with the Building Official before re-decking or ordering trusses.

6.0% -- the Idaho state rate, with no local add-on. Idaho Code 63-3619 imposes the state sales tax "at the rate of six percent (6%)". Idaho has only two kinds of local sales tax, and neither reaches roofing work in Jefferson County. The first is the resort-city local-option tax, which Idaho Code 50-1044 confines to a resort city "with a population not in excess of ten thousand (10,000)"; the Idaho State Tax Commission publishes the list of cities that levy one, and neither Rigby nor any other Jefferson County city appears on it, nor does a county have that authority. The second is an auditorium-district tax, which the Tax Commission states "can charge a local sales tax only for short-term lodging (30 days or less)" and so never reaches roofing work. Idaho counties levy no sales tax at all. HOW A ROOF IS TAXED, WHICH MATTERS MORE THAN THE RATE: the Tax Commission's contractor guidance states that "Idaho sales tax law says contractors are the consumers (end users) of all the goods they use. As a result, they must pay sales tax on all purchases", and it names roofers among the contractors it covers. The roofer pays the 6% on materials at the supply house; the homeowner's invoice carries no sales tax line at all, on materials or on labour, because "a contractor doesn't charge sales tax to the customer" and the tax is absorbed into the bid. The Commission adds that "if sales tax is charged on the bill, the customer can refuse to pay it." A customer's own sales-tax exemption does not carry over to the contractor.