Unincorporated Ada County building permits

Requirements

• Building permit required for all new residential construction, additions, and structural alterations in unincorporated Ada County
• Submit complete digital PDF application package (application form + all plan sheets as individual files, not a single zip) by email
• Site plan showing proposed and existing structures in relation to all property lines, easements, wells, and septic tanks/drainfields
• Foundation plan with layout, venting, and section details showing sizes, depths, and grade
• Floor framing plan with member specifications, sizes, spans, support, and subfloor details
• Floor plan detailing conditioned, unconditioned, and covered areas with windows and door openings labeled
• Braced wall line plan with methods noted and panel lengths dimensioned
• Wall/building sections with insulation R-values, U-factors, and framing specifications
• Roof framing plan with venting, spacing, framing, and connection details
• HVAC design and layout required for new dwellings — Manual J, D, and S (or Wrightsoft) submittal required
• Elevations for all sides of the structure
• Electrical layout showing switches, receptacles, lights, vents, and smoke/CO detectors
• Post-frame/pole buildings: stamped engineering required; steel buildings: stamped engineering including foundation design required
• Central District Health approval required if property is on septic
• ACHD impact fees for residential dwellings accepted at the Building Division (receipt copy required if paid directly to ACHD)

Required documents

• RequiredBuilding Permit Application (Rev. 02.06.2026)Ada County building permit application form; available at adacounty.id.gov/developmentservices/permitting-division/applications-forms-templates/
• RequiredBuilding Permit Application Checklist — Single Family DwellingsChecklist of all required plan elements for single-family residential permits; available on the Applications, Forms, and Templates page
• RequiredFull Plan Set (Site Plan, Foundation, Floor Framing, Floor Plan, Braced Wall, Wall Sections, Roof Framing, Elevations, Electrical Layout, Details)Dimensioned and to-scale drawings per the Ada County Adopted Codes and Amendments for Construction checklist (proposed checklist PDF); each file submitted individually — not in a zip
• RequiredManual J, D, and S (or Wrightsoft)HVAC design submittal required for new dwellings; submitted as an individual file alongside plans
• OptionalSimple Dwelling Additions ChecklistApplication and plan requirements for simple additions, private garages, carports, patio covers, and elevated decks; available on the Applications, Forms, and Templates page
• OptionalCentral District Health ApprovalRequired when property is served by septic and project involves any addition, expansion, or significant alteration; contact CDH at 208-327-7499

Fee schedule

Requirements

• Required for new commercial/industrial buildings, multi-family structures (3+ units), tenant improvements, and change-of-occupancy projects
• Submit complete digital PDF application package (application form + all plan sheets as individual files, not in a zip) by email to mechanical@adacounty.id.gov
• Commercial Building Permit application form required
• Full plan set drawn to scale and dimensioned; not all items apply to all structures
• Post-frame and steel buildings require stamped engineering including foundation design
• Structural calculations may be required by the plans examiner during review for non-standard materials or non-prescriptive construction

Required documents

• RequiredCommercial Building Permit Application (.docx)Ada County commercial building permit application; available at adacounty.id.gov/developmentservices/permitting-division/applications-forms-templates/
• RequiredFull Commercial Plan SetAll required drawings per plan examiner direction — site plan, floor plan, structural plans, architectural plans; each submitted as an individual PDF file

Fee schedule

Requirements

• All installation, replacement, or repair of heating, cooling, ventilation, or fuel gas systems
• Residential: submit Residential Mechanical Permit application by email to mechanical@adacounty.id.gov
• Commercial: submit Commercial Mechanical Permit application by email to mechanical@adacounty.id.gov
• Idaho contractor registration number required for commercial applicants

Required documents

• RequiredResidential Mechanical Permit Application (2025)One-page application listing all mechanical work items; available at adacounty.id.gov/developmentservices/permitting-division/applications-forms-templates/
• OptionalCommercial Mechanical Permit Application (2025)Commercial mechanical permit form with total bid amount; available on the Applications, Forms, and Templates page

Fee schedule

Requirements

• Tier 1 (residential, area of disturbance less than 1 acre): site plan/drainage plan with property lines, easements, structures, well/septic locations, area of disturbance, stormwater flow arrows, and narrative
• Tier 2 (disturbance 1 acre or greater): all Tier 1 items plus plan prepared by a design professional; soils report may be required
• Tier 3 (commercial/drainage projects, new subdivisions): detailed drainage plan drawn to scale with all grading, drainage system essentials, stormwater routing, discharge flows, and evidence of consent from affected irrigation/drainage entities
• Submit Grading & Drainage Application with all required documents to mechanical@adacounty.id.gov

Required documents

• RequiredGrading & Drainage Application (2025)Ada County grading/drainage permit application listing all submittal requirements by tier; available at adacounty.id.gov/developmentservices/permitting-division/applications-forms-templates/
• RequiredSite Plan / Drainage PlanRequired for all tiers — must show property lines, easements, existing structures, well/septic locations, area of disturbance, stormwater flow direction
• OptionalDesign Professional Drainage Plan (Tier 2 and Tier 3)Tier 2: prepared by a design professional. Tier 3: full drainage plan drawn to scale with calculations; soils report may be required

Fee schedule

Requirements

• Swimming Pool/Spa Permit Application plus full plans required
• Barrier acknowledgment letter (Page 2 of the combined pool application) signed by both the contractor and the property owner must be submitted and received by Ada County BEFORE the building permit is issued
• All pools/spas must comply with 2018 ISPSC barrier requirements
• Final inspection must be requested within one year of permit issuance or an alert is placed on the property preventing further building permits

Required documents

• RequiredSwimming Pool Permit Application (Combined 2026) — including Barrier Acknowledgment LetterTwo-page application: Page 1 is the permit application; Page 2 is the required barrier acknowledgment letter that must be signed by contractor and property owner before the permit is issued. Available at adacounty.id.gov/developmentservices/permitting-division/applications-forms-templates/
• RequiredPool/Spa PlansPlans and specifications for pool/spa construction; submit as individual PDF files by email

Fee schedule

Requirements

• Property must be a 'farm' — 5 acres or larger in agricultural use with agricultural exemption
• Structure must be for agricultural use only (not a dwelling; not personal item storage)
• Accessory Use / Zoning Certificate approval required through Ada County Development Services before construction
• Site plan (drawn to scale/dimensioned) including all existing and proposed easements, property lines, structures, setbacks, and well/septic locations
• Detailed letter describing the proposed structure and its use
• Property owner signature consenting to the application and site inspections

Required documents

• RequiredAgricultural Structure Application (2025)Two-page application form for agricultural structures under ACC 8-2-23-2; available at adacounty.id.gov/developmentservices/permitting-division/applications-forms-templates/
• RequiredSite Plan (drawn to scale/dimensioned)Showing all existing and proposed easements, property lines, structures, setbacks, and well/septic locations
• RequiredDetailed LetterDescribing the proposed structure and its agricultural use

Fee schedule

Requirements

• Building permit required for the structural/mounting portion, issued by Ada County Development Services under the Ada County Building Code
• Valuation for fee purposes includes the structural elements, racking, mounting elements, rails, and labor — but excludes the solar panels/equipment and inverters, per the County's own Building Permit Valuation Guidelines
• The ELECTRICAL interconnection portion of a solar PV installation (inverter tie-in, NEC compliance) requires a SEPARATE permit issued by the State of Idaho DOPL/Division of Building Safety, not Ada County — Ada County Development Services issues no electrical-permit type
• General inspection minimum fee of $100 applies per the County's Plan Review and Inspection Fees table

Required documents

• RequiredBuilding Permit Application (Building Division)Standard Ada County building permit application for the structural/mounting portion; valuation excludes panels/inverters per the County's valuation guidelines
• RequiredDOPL/Division of Building Safety Electrical PermitSeparate state-issued permit required for the electrical interconnection portion — obtained directly from the state, not through the County

Fee schedule

Requirements

• Electrical permit required for EVSE circuit/branch-circuit and charger installation — issued by Idaho DOPL, not Ada County, since Ada County Development Services issues no electrical permits
• Homeowners performing electrical work on their own primary/secondary residence may pull a Homeowner Electrical Permit directly from DOPL; otherwise a licensed Idaho electrical contractor must pull the permit
• Residential EVSE added to an existing dwelling is billed under DOPL's 'Existing Dwelling Unit' fee (per inspection) — there is no separate EV-charger fee category in the DOPL fee rule
• Commercial/multi-family EVSE installations are billed under DOPL's wiring-cost-based commercial/industrial fee formula (percentage of total wiring cost, tiered by valuation)
• No county building permit is required for a standalone EVSE circuit unless it is paired with structural work (e.g., a new carport/canopy), in which case a separate Ada County building permit applies to that structural scope

Required documents

• OptionalHomeowner Electrical Permit Application (DOPL)For homeowners wiring an EVSE circuit at their own primary/secondary residence; available at dopl.idaho.gov
• OptionalContractor Electrical Permit Application (DOPL)For licensed Idaho electrical contractors installing EVSE circuits, whether residential or commercial; available at dopl.idaho.gov

Fee schedule