Unincorporated Ada County building permits
VerifiedDepartment contacts, adopted codes, permit types, fees, and gotchas for Unincorporated Ada County, Idaho.
Last verified 2026-06-29 · Source · Embed this page’s badge · Version history
Building department
- Address
- 200 W. Front Street (Ada County Courthouse, 2nd Floor), Boise, ID 83702-7300
- Phone
- 208-287-7900
- Office hours
- Mon–Fri 8:00 AM – 5:00 PM
- Website
- Official site
- Permit portal
- Apply online at Unincorporated Ada County's portal
Inspection guide
See how inspections work in Unincorporated Ada County — sequence, scheduling & re-inspection fees.
Codes adopted
Idaho adopts a statewide baseline building code set under the Idaho Building Code Act (Idaho Code Title 39, Chapter 41) and IDAPA rules administered by the Idaho Division of Occupational and Professional Licenses (DOPL). Effective January 1, 2021, the statewide baseline includes the 2018 International Building Code (IBC), 2020 Idaho Residential Code (based on the 2018 IRC Parts I–III and IX with Idaho amendments), 2020 Idaho Energy Conservation Code (based on the 2018 IECC with Idaho amendments), 2018 International Existing Building Code (IEBC), 2018 International Mechanical Code (IMC), 2018 International Fuel Gas Code (IFGC), and 2018 International Fire Code (IFC). The National Electrical Code is adopted separately by the Idaho Electrical Board (IDAPA 24.39.10), not bundled with the building code: Idaho enforces the 2023 NEC, effective July 1, 2024 (the state used the 2017 NEC with amendments before that and skipped the 2020 edition). Local jurisdictions must enforce the state baseline and may adopt amendments only where those amendments are at least as stringent as the state-adopted editions; local amendments may not be less restrictive. Enforcement is local — each city or county issues permits and performs inspections. Always confirm the current adopted edition and any local amendments with your specific jurisdiction before submitting plans.
- 2018 International Building Code (IBC) — adopted via Ordinance #919, Ada County Code
- 2018 International Residential Code (IRC) — adopted via Ordinance #919
- 2018 International Existing Building Code (IEBC) — adopted via Ordinance #919
- 2018 International Energy Conservation Code (IECC) — Commercial Provisions; Residential as modified by Idaho Statute Title 39 Chapter 41; adopted via Ordinance #919
- 2018 International Mechanical Code (IMC) — adopted via Ordinance #919
- 2018 International Fuel Gas Code (IFGC) — adopted via Ordinance #919
- 2018 International Urban-Wildland Interface Code (IUWIC) — adopted via Ordinance #919
- 2018 International Swimming Pool and Spa Code (ISPSC) — adopted via Ordinance #919
Permit types & fees
Residential Building Permit (New Construction / Addition)
Required for new single-family dwellings, additions, detached garages, shops, carports, patio covers, elevated decks, and accessory structures in unincorporated Ada County. Ada County Building Division has issued permits since 1975 under the Ada County Building Code. Plans Examiners review construction drawings and Building Inspectors perform on-site inspections. Applications are submitted digitally as PDF files by email to the Building Division.
Commercial Building Permit (New Construction / Tenant Improvement)
Required for all new commercial, industrial, and multi-family buildings (three or more units), tenant improvements, remodels, and change-of-use projects in unincorporated Ada County. Governed by the 2018 International Building Code (IBC) as adopted by Ada County Ordinance #919. Applications submitted digitally by email.
Mechanical / HVAC Permit
Required for heating, ventilation, air conditioning, fuel gas piping, and related mechanical installations in unincorporated Ada County. Residential and commercial mechanical permits are both issued by Ada County Development Services — Building Division. Governed by the 2018 International Mechanical Code (IMC) and 2018 International Fuel Gas Code (IFGC) as adopted via Ordinance #919. Applications submitted digitally by email.
Grading & Drainage Permit
Required for grading and drainage work in unincorporated Ada County. Three tiers apply based on the area of disturbance and project type: Tier 1 for residential grading under one acre, Tier 2 for disturbance of one acre or more, and Tier 3 for commercial projects and new subdivisions. Governed by the 2018 International Building Code and Ada County Code (ACC 8-6). Applications submitted digitally by email.
Swimming Pool / Spa Permit
Required for in-ground swimming pools, above-ground pools, and spas in unincorporated Ada County. Governed by the 2018 International Swimming Pool and Spa Code (ISPSC) as adopted via Ordinance #919. A special barrier acknowledgment letter signed by the contractor and property owner is required BEFORE Ada County will issue the pool building permit. Unfinished pool permits (no final inspection within one year) trigger a property alert preventing new building permits.
Agricultural Structure Permit (Zoning Certificate)
An agricultural structure in unincorporated Ada County requires the issuance of a Zoning Certificate before construction begins. Qualifies only for structures on a 'farm' (5 acres or more in agricultural use with agricultural exemption) that are used exclusively for agricultural purposes — not for dwellings or personal item storage. Application fee is $100. Governed by Ada County Code ACC 8-2-23-2.
Solar Photovoltaic (PV) Permit
Required for installation of rooftop or ground-mount solar photovoltaic systems in unincorporated Ada County. The structural/mounting portion is a building permit issued by Ada County Development Services, using the same valuation-based fee table as other building work, with a solar-specific valuation rule: the taxable valuation for a solar PV permit includes the structural elements, racking, mounting elements, rails, and labor, but EXCLUDES the solar panels/equipment and inverters themselves. Electrical interconnection work is permitted separately by the State of Idaho (DOPL/Division of Building Safety), not the County, since no electrical-permit type is issued by Ada County Development Services.
EV Charger / EVSE Electrical Permit
Installation of an electric vehicle charging station (EVSE) in unincorporated Ada County is an electrical permit — and, as with all electrical work in the county, it is issued by the State of Idaho Division of Occupational and Professional Licenses (DOPL, formerly Division of Building Safety), not by Ada County Development Services, which issues no electrical-permit type at all. There is no distinct EV-charger/EVSE line item in DOPL's fee rules (IDAPA 24.39.10.500); a residential EVSE circuit added to an existing home is billed under the 'Existing Dwelling Unit' per-inspection fee, and a commercial charging-station installation is billed under the wiring-cost-based commercial/industrial fee formula.
New residential construction activity
New privately-owned residential construction onlyHousing units authorized by building permits for new privately-owned residential construction — this is not total permit volume (no commercial permits or remodels).
- Latest month (2026-05)
- 570units
456 buildings · $156.9M valuation
- Trailing 12 months
- 5,275units
12 of 12 months reported · #1 in Idaho coverage by units
- Year to date (2026 YTD through 2026-05)
- 2,429units
2,246 buildings · $741.2M valuation
- Full year 2025
- 5,221units
4,691 buildings · $1,545.1M valuation
County-wide figures: BPS reports county-wide totals; jurisdiction is the unincorporated remainder — county totals include incorporated cities; county file row: 'Ada County' (co2605c.txt, 16/001); place file also carries 'Ada County Unincorporated Area' (place code 99990) as a possible Phase-1 alternative
Source: U.S. Census Bureau, Building Permits Survey (BPS), 2026-05 vintage. Census survey data — separate from the permit-requirements verification above. All Idaho building activity
Tips & gotchas
- All applications are submitted digitally by email to mechanical@adacounty.id.gov. Submit each document as a separate PDF file — not merged into a single PDF and not compressed in a zip archive. Zips take longer to process.
- Payment is required before processing begins. Only e-checks ($3.00 flat) and credit cards (2.4% convenience fee, minimum $2) are accepted.
- Electrical permits (wiring, panels, electric water heaters) are issued by the Idaho Division of Building Safety (DBS), NOT Ada County. Contact DBS at 1-800-839-9239.
- Inspection requests must be made the day before the inspection is needed — by phone before 4:30 PM, or by email before midnight. AM/PM scheduling is accommodated when possible but not guaranteed.
- Ada County does NOT require a building permit for installing a fence. Fencing standards still apply under ACC 8-5-3-44, and corner lot clear vision triangles under ACC 8-1A-2.
- Swimming pool permits have a one-year final inspection requirement. If a final is not requested within one year, a property alert is placed preventing new building permits on the parcel.
- Central District Health (CDH, 208-327-7499) approval is required for any addition, expansion, or significant alteration on a property served by a septic system — regardless of whether plumbing work is involved.
- Projects in a Planned Community require HOA Design Approval before Ada County issues a building permit.
- Post-frame/pole buildings require stamped engineering. Steel buildings require stamped engineering including foundation design. Stick-framed walls exceeding 12 feet require engineering for tall walls and shearwall design.
- HVAC design (Manual J, D, and S) must accompany the building permit application for new dwellings — not a separate permit submittal.
- Fee schedule updated November 2025 in conjunction with the new Ada County Zoning Code (effective November 2025). New ACHD impact fees effective March 1, 2026.
- Ada County Development Services is located on the 2nd floor of the Ada County Courthouse, 200 W. Front Street, Boise. Hours: Mon–Fri 8:00 AM – 5:00 PM.