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Personal Use Energy Project Permit (Rooftop/Ground-Mount Solar) in Unincorporated Twin Falls County, Idaho

Required for residential ('personal use') solar and wind energy systems in unincorporated Twin Falls County under Title 8, Chapter 21 (Energy Production) of the County Code, adopted March 2024. Per County Code Section 8-21-3(B): 'A siting permit and building permit is required prior to installation of any personal use energy project.' A personal-use project is a small system (per the ordinance's own drafting materials, capacity of 200 kW or less, footprint under 200 sq ft, associated with a single-family dwelling) — distinct from Small Scale (200 kW-10 MW) and Large Scale commercial energy projects, which instead require a Conditional Use Permit through the Planning & Zoning Division. The building-permit component is issued by the same Building Department and reviewed under the 2018 IBC/IRC as the county's general residential-building-permit; electrical interconnection work is permitted separately by the Idaho Division of Building Safety (state), not the county.

Verified 2026-07-20 · Source

When you need this permit

  • A Siting Permit (Planning & Zoning) AND a Building Permit (Building Department) are both required prior to installing a personal-use solar or wind energy system, per Twin Falls County Code Section 8-21-3(B)
  • Personal-use energy project: total capacity of 200 kW or less, not encumbering more than 200 sq ft, associated with a single-family dwelling — larger systems must instead go through the Small Scale (200 kW-10 MW) or Large Scale Conditional Use Permit process under Chapter 21
  • Applicant must coordinate/document any state or federal permits or licenses related to the project and provide copies to the county (Section 8-21-3(C))
  • Site review may be required for proposed electric generating projects per Section 8-21-3(D)
  • The building-permit component follows the same submittal requirements as the general residential-building-permit entry (site plan, structural details for roof/ground mounting) where applicable to the racking/mounting structure
  • Electrical permitting/inspection for the PV interconnection is handled by the Idaho Division of Building Safety (state), not Twin Falls County — see the county's electrical-permit sourcing on the residential-building-permit entry

Required documents

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Fee schedule

Personal Use (Wind/Solar) Siting PermitTwin Falls County Community Development Services Fee Schedule, effective 9/1/2025 (TFCO-BLD-FEES-2025-base-FINAL.pdf), Zoning Fees table — confirmed by rendering the fee-schedule PDF page to an image and reading the table directly, since the PDF's text layer garbles the multi-column row/value alignment for this section. Flat fee, distinct from the Conditional Use Small Scale (Wind/Solar) fee ($3,000 plus $75/tower or $50/acre covered solar), which applies only to systems above the personal-use size threshold.
$675.00
Building Permit Fee (structural/mounting component)No separate solar-specific building-permit fee line was found on the county's fee schedule; the structural/mounting portion of a personal-use system is billed under the same valuation-based table as residential-building-permit
Valuation-based per the general residential building-permit fee schedule

Review timeline

Plan review
Not published — contact the department

How long did your Personal Use Energy Project Permit (Rooftop/Ground-Mount Solar) permit actually take in Unincorporated Twin Falls County?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Rough / Structural (if applicable)

    Mounting/racking structural attachment verified before covering, per the paired building permit

  2. 2

    Final

    Installation complete per approved siting and building permits; electrical interconnection final inspection is separately performed by the State of Idaho (Division of Building Safety)

See the full Unincorporated Twin Falls County inspection guide — scheduling & re-inspection fees →

Tips

  • Twin Falls County requires TWO permits for a residential solar or wind install: a Siting Permit ($675 flat fee) from Planning & Zoning, AND a Building Permit from the Building Department for the structural/mounting work — do not assume one permit covers both.
  • The $675 Personal Use (Wind/Solar) fee applies only to small systems (per the ordinance's own definition, 200 kW capacity or less and under 200 sq ft footprint, tied to a single-family dwelling); larger installations require a Small Scale or Large Scale Conditional Use Permit at substantially higher fees ($3,000-$5,000 plus per-tower/per-acre charges).
  • Electrical permitting for the PV interconnection itself goes through the Idaho Division of Building Safety (state), not the county — call 1-800-955-3044 or visit dbs.idaho.gov, consistent with how the county handles all electrical permits.

Frequently asked questions

Two permits: a Siting Permit from Planning & Zoning ($675 flat fee) and a Building Permit from the Building Department for the mounting/structural work, per Twin Falls County Code Section 8-21-3(B). This applies to 'personal use' systems (200 kW or less, under 200 sq ft, associated with a single-family dwelling). Electrical interconnection is separately permitted by the Idaho Division of Building Safety, a state agency.

The Personal Use (Wind/Solar) Siting Permit fee is $675.00 flat, per the Twin Falls County Community Development Services Fee Schedule effective 9/1/2025. A separate valuation-based Building Permit fee also applies for the structural/mounting component, using the same fee table as general residential construction.

Unincorporated Twin Falls County does not publish a plan-review timeline for this permit. Contact Twin Falls County Community Development Services — Building Department at 208-734-9490 for current turnaround.

You'll need: Siting Permit Application (Personal Use Energy Project); Building Permit Application. See the required-documents checklist on this page for details on each.

Unincorporated Twin Falls County requires 2 inspection(s) for a personal use energy project permit (rooftop/ground-mount solar), in order: Rough / Structural (if applicable), Final. Schedule each through Twin Falls County Community Development Services — Building Department (208-734-9490).

Apply through Twin Falls County Community Development Services — Building Department at 630 Addison Avenue West, Suite 1100, Twin Falls, ID 83301. Phone: 208-734-9490. Office hours: Mon–Fri 8:00 AM – 5:00 PM (Building Department closed for lunch 12:30 PM – 1:30 PM). Official information: https://twinfallscounty.org/community-development-services/.

Unincorporated Twin Falls County, Idaho has adopted: 2018 International Building Code (IBC) with Idaho Amendments; 2018 International Residential Code (IRC) with Idaho Amendments; 2018 International Energy Conservation Code (IECC) with Idaho Amendments; 2018 International Mechanical Code (IMC) with Idaho Amendments; 2018 International Fuel Gas Code (IFGC) with Idaho Amendments; 2018 International Existing Building Code (IEBC) with Idaho Amendments; 2018 International Fire Code (IFC) with Idaho Amendments; 2018 Idaho Manufactured Home Installation Standards. Local amendments apply — see the Unincorporated Twin Falls County overview page for the full list.

Other permits in Unincorporated Twin Falls County

Residential Building Permit (New Construction / Addition)Commercial Building Permit (New Construction / Tenant Improvement)Mechanical / HVAC PermitElectric Vehicle (EV) Charging Station / EVSE Permit

Personal Use Energy Project Permit (Rooftop/Ground-Mount Solar) in other cities

American Falls, IdahoAmmon, IdahoBlackfoot, IdahoBoise, IdahoBuhl, IdahoBurley, IdahoCaldwell, IdahoCascade, Idaho

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