Madison County, Idaho Building Permit Guide

Building permits for unincorporated Madison County are issued by the County’s Building Department in Rexburg, which has permitted construction since 1976. Applications start in the County’s online Permit Portal, review takes at least 10 working days once the file is complete, and the permit fee comes from the valuation table in County Code 103-1: $2,155.25 on a house valued at $300,000, with a $500 non-refundable deposit paid up front and applied to it. The County says mechanical, electrical and plumbing permits for its sites are handled through the City of Rexburg building department, while the State’s permit map lists electrical and plumbing there as state permits.

When does Madison County require a permit?

The Building Department splits its applications by project type, and each structure on a property needs its own permit unless the Building Official approves otherwise.

Building more than one dwelling unit on a parcel needs approval through Planning and Zoning. County Code exempts single-family homes, and buildings of up to two units that stand at least 10 feet from the nearest building, from the code requirement for automatic fire sprinklers.

Who issues Madison County building permits?

The County Building Department reviews construction drawings for code compliance and carries out the site inspections for land outside the cities. David Decker is the Building Official and building inspector.

The county has two incorporated cities, and neither is permitted by the County:

• Rexburg has its own Building Department and issues city building, electrical, plumbing and HVAC permits. The County says Rexburg also handles the mechanical, electrical and plumbing permits for county building sites, and Rexburg’s application portal states that it carries certain applications and permits for both the City and Madison County.
• Sugar City takes building permit applications through its own online iWorQ application, calculates the fee once the plans are approved, and schedules inspections from the same permit page. It also has city fence and mechanical permit forms, while the State’s permit map lists electrical and plumbing permits in Sugar City as state permits.

Land in a city’s area of impact is still a County permit: County Code 105-7 says Madison County issues the building permits and carries out the construction inspections there. The county application asks whether the parcel lies in an area of city impact, so have that answer ready.

County applications and the Permit Portal

Applications may be started in the County’s Permit Portal, where they are separated by project type and PDF plans and supporting documents can be uploaded. The same applications are also posted as PDFs:

• Building Permit Application (2026 edition), for detached one- and two-family dwellings and their accessory structures.
• Agricultural Exemption Permit Application Packet, with a signed Understanding of Policy form.
• Manufactured Home Permit.
• Solar Permit, Demolition Permit and Fire & Flood Permit.
• Affidavit of Legal Interest, available from the Building Department, for an applicant who is not the legal owner.

On an owner-built project the property owner signs the application as both owner and contractor.

Madison County permit fees

Building permit fees are set out in County Code 103-1, “Building Fees”, the fee schedule adopted by Ordinance 481 on May 13, 2024. For homes and additions the County works out the value of the job from the Building Valuation Data of the current adopted year and then reads the fee from this table, which the code says is charged on all building permits.

Worked example: a house valued at $300,000 pays $1,035.25 for the first $100,000 plus 200 x $5.60 ($1,120) for the rest, a permit fee of $2,155.25. The schedule lists no percentage plan review fee for houses.

Two of the County’s web pages still quote older amounts. The Manufactured Homes page and the Agricultural Building page each ask for $150 plus a $45 review fee at submittal, while the adopted schedule in the code sets $200, $300 or $400 for a manufactured home and $150 plus a 10% review fee for an agricultural permit. The County’s inspection checklist says that skipping an inspection, or carrying on after a failed one, leads to a 30% increase in the permit cost; the code’s own row for proceeding after failing to meet code is $65 before the next inspection. A Certificate of Occupancy is not issued until all fees and fines are paid.

Electrical, plumbing and mechanical permits

Two official sources describe trade permits for unincorporated Madison County differently.

• The County’s Building Department page says mechanical, electrical and plumbing permits and inspections are handled through the City of Rexburg building department and are no longer issued by the State of Idaho. Rexburg’s online application portal, at apply.rexburg.org, says it includes certain applications and permits for the City of Rexburg and for Madison County.
• The State’s permit map, last updated on September 29, 2026, lists electrical and plumbing permits for unincorporated Madison County as state permits and HVAC as a County permit.

Ask the Building Department (208-359-6262) which office is issuing the permit for your trade before paying for a state permit. The state Division of Occupational and Professional Licenses answers on 208-334-3233.

The County’s own code list names the 2017 National Electrical Code and the 2017 Idaho Plumbing Code alongside the 2018 International Mechanical, Fuel Gas and Fire Codes and the 2013 edition of NFPA 72 for fire alarms. Properties with significant slopes may be reviewed by the Madison County Fire Marshal for emergency access.

Application documents and site approvals

In a mapped floodplain, a Floodplain Development Permit from Planning and Zoning and a Preliminary Elevation Certificate are needed before the building permit, and a Final Elevation Certificate before the Certificate of Occupancy. Wetlands on or beside the property, and any proposed bridge, bring in the U.S. Army Corps of Engineers.

The prescriptive insulation table on the application is for Climate Zone 6B: R-49 ceilings, R-22 or R-13 plus R-5 wood frame walls, R-30 floors over unconditioned space, R-15 or R-19 basement and crawlspace walls, and R-10 slab edges. A manufactured home must be shown to withstand a 50 psf snow load.

How to apply for a Madison County permit: 6 steps

Inspections and permit completion

The County publishes an inspection checklist for each permit type. For a house it runs from setbacks (and the flood certificate where one applies) through footing and foundation, slab, sheathing and framing to the final.

• The permit number and site address must be posted and clearly visible from the roadway before an inspection; without them the inspection fails or is not carried out.
• A portable toilet or approved restroom access, and a dumpster or approved waste disposal method, are required on every job site.
• Working out of the approved inspection order can bring additional fees, a stop work order or re-inspection.
• Nothing may be moved in before the Certificate of Occupancy. The County counts furniture, mattresses, linens, small kitchen appliances, washers and dryers, and vehicles or boats parked in the garage as occupancy; tools, building materials, large appliances and fixtures are allowed.

Local Madison County details

Agricultural buildings: the exemption covers livestock shelters, silos and storage for equipment used only in agriculture. The packet still requires a site plan showing setbacks from side property lines, the center line of county roads and waterways, and two paper plan sets plus a PDF.

Covenants: the County does not enforce private covenants and asks the applicant to certify that the project does not violate them.

Burning: burning construction waste is prohibited unless the Madison County Fire District issues a permit.

Code update: the Building Department has posted a 2024 proposed building code update; the editions it lists as adopted remain the 2018 International Codes.

Planning office: Planning and Zoning shares the building at 134 E. Main Street (Suite 208) and administers the Unified Development Code, flood permits and land use table.

Idaho building code

Idaho’s building codes are set statewide and enforced by the cities and counties that run a building program: the 2018 International Building Code and the Idaho Residential Code (based on the 2018 IRC), the 2018 Idaho Energy Conservation Code, the 2023 National Electrical Code, and a state plumbing code based on the 2015 Uniform Plumbing Code rather than the International Plumbing Code. Idaho’s adopted codes

Official Madison County permitting resources

These are the primary sources behind this guide. Codes, fee schedules and procedures change — confirm the position for your filing date.

• Idaho DOPL building codes
• Idaho DOPL building FAQ
• Idaho DOPL HVAC FAQ
• City of Rexburg building permit applications
• City of Rexburg online application portal (apply.rexburg.org)
• Madison County Code 103-1, Building Fees (Ordinance 481)
• Madison County building permit application and checklist (earlier fillable edition)
• Madison County Building Department
• Madison County building permit requirements and 2026 application
• Madison County Permit Portal
• Madison County agricultural building permits
• Madison County manufactured home permits
• Madison County Planning and Zoning
• City of Sugar City building permits

Madison County building permit FAQs

Does Rexburg issue Madison County building permits?

No. Rexburg permits buildings inside the city, and the County Building Department permits unincorporated land. The County’s page does, however, send mechanical, electrical and plumbing permits for its sites through the City of Rexburg building department, while the State’s permit map lists electrical and plumbing there as state permits.

How long does a county building permit take?

The review needs at least 10 working days after every required document is in and the application is deemed complete.

How much is a building permit in Madison County?

The fee comes from the valuation table in County Code 103-1 (Ordinance 481, 2024). A house valued at $300,000 pays $2,155.25, and a job valued at $500 or less pays $65. A $500 deposit for a dwelling or $100 for an accessory structure is paid with the application and applied to the fee.

Does a new home need septic approval first?

Yes. A septic permit from Eastern Idaho Public Health is required before the building permit is approved.

Can someone who is not the owner apply?

Yes, with an Affidavit of Legal Interest notarized by both the owner and the applicant.

Do agricultural buildings need a permit?

They use the Agricultural Exempt Permit. The fee schedule in County Code 103-1 sets a $150 fee plus a 10% review fee and a Planning and Zoning review fee; the County’s Agricultural Building page still quotes $150 plus a $45 review fee.

How much is a manufactured home permit in Madison County?

County Code 103-1 sets $200 for a single-wide, $300 for a double-wide and $400 for a triple-wide. The County’s Manufactured Homes page still quotes $150 plus a $45 review fee.

Who permits construction in Sugar City?

Sugar City itself, through its online building permit application.

Simplify Madison County permitting with Alliance Permitting

Alliance Permitting is a permit documentation and submission company in Idaho. We prepare your paperwork, file it correctly and coordinate with the permitting authority through issuance. We are not a contractor and we do not perform licensed plan review or inspections; that work stays with your licensed team and the jurisdiction.

This guide is provided by Alliance Permitting for general information about Madison County permitting. Requirements, fees, and procedures change; confirm details with the permitting authority before relying on them.