Columbia County Building Permit Guide (Unincorporated Area)

Permit Authority

All properties in unincorporated Columbia County (outside the incorporated cities of Dayton and Starbuck).

Department

Columbia County Planning and Building Department

Address

115 E. Main Street, Dayton, WA 99328

Phone

(509) 382-4676

Website

https://www.columbiaco.com/69/Planning-and-Building

Online Permit Portal

Application Process

1. Download or obtain building permit application forms from https://www.columbiaco.com/511/Building-Permit-Applications
2. Contact Columbia County Planning and Building at (509) 382-4676 to confirm requirements for your specific project type.
3. Prepare all required documents: site plan, construction plans, foundation design, energy code worksheets, and project-specific materials.
4. Submit the complete application package in person at 115 E. Main Street, by mail, or via email. Email submissions must be under 20 MB per email.
5. Staff will confirm receipt within two business days and initiate review for compliance with zoning, Comprehensive Plan, critical areas, shoreline management code, SEPA, flood hazard zones, and the 2021 Washington State Building Code.
6. Permit is issued upon completion of all reviews. Fees are due at issuance.
7. Contact (509) 382-3941 to schedule inspections (minimum 24-hour advance notice). The permit will list all required inspection stages.
8. Final inspection and Certificate of Occupancy upon satisfactory completion.

Typical processing time: 2-3 weeks for complete applications. Review time depends on project complexity and whether SEPA, shoreline, or critical areas review is required.

Source: Columbia County Planning and Building Department

General Requirements

Per Columbia County Code Chapter 15.10, no owner or authorized agent may erect, construct, enlarge, shore, underpin, repair, improve, convert, or otherwise alter any building or structure without first obtaining a building permit.

Required Documents

• Completed building permit application form
• Site plan showing all structures on the parcel with distances; location of proposed structure; location of water/well, sewer/septic, gas, and electrical lines and connections; location of decks, retaining walls, and significant landscape elements; location and dimensions of all easements
• Structural/construction plans
• Foundation design documentation
• Energy code compliance worksheets (available at https://www.columbiaco.com/507/Building-Information-and-Resources)
• Any materials specific to project type (commercial, mechanical, plumbing, etc.)
• Commercial Building Permit form for commercial projects (revised November 2025)

Permit validity

Permit must be obtained within 6 months of application. Issued permit expires if construction does not commence within 6 months of issuance.

Building code

2021 International Building Code (IBC) with Washington State Amendments (effective March 15, 2024)

Owner-builder

Owner-builders may apply for their primary residence; confirm eligibility with Columbia County Planning and Building at (509) 382-4676.

Contractor requirements

All contractors must hold a valid Washington State L&I registration number. Registration number must appear on all advertising, bids, vehicles, and online presence.

Fees

Minimum permit fee

Based on project valuation; see county fee schedule

Permit fee formula

Based on construction value; see county fee schedule PDF for complete fee tables

Reinspection fee

$75.00 minimum, up to double the original permit fee; hourly rate $65.00

Payment note

Online payment via Point & Pay (2.5% convenience fee, $2.00 minimum). Also accepts checks payable to Columbia County Treasurer or exact cash in person.

Fees change. Verify current amounts at the official fee schedule (effective Per Columbia County Resolution 2024-42, Exhibit B).

Work That Does NOT Require a Permit

• One-story detached accessory structures (tool sheds, storage sheds, playhouses) not exceeding 200 sq. ft. of floor area
• Fences not over 6 feet in height
• Retaining walls not over 4 feet in height (measured from footing bottom to wall top), not supporting a surcharge
• Painting, papering, tiling, carpeting, cabinets, countertops, and similar finish work
• Prefabricated swimming pools less than 24 inches in depth
• Swings and playground equipment
• Agricultural structures used exclusively for agricultural purposes (equipment storage, farm vehicle parking) where no one lives, structure not open to public, and no agricultural product processing or packaging occurs

Important: Even for exempt work, the 2021 Washington State Building Code and local setbacks must be met. If plumbing, heating, or electrical work is part of an otherwise exempt structure, those trade permits are still required. All electrical work requires Washington State L&I permits. Agricultural structure exemptions are fact-specific — obtain written confirmation from Columbia County before assuming exemption.

Inspections

How to Schedule

• (509) 382-3941 (phone)

Scheduling deadline

Requests must be submitted with minimum 24-hour advance notice.

Inspection hours

Monday–Friday, business hours; Columbia County Planning and Building hours.

Typical inspection sequence: Typical sequence for new construction: footing/foundation, framing/rough-in, insulation, and final inspection. Specific inspection stages listed on the issued permit.

Additional Resources

• Building code: 2021 International Building Code (IBC) with Washington State Amendments (effective March 15, 2024)
• Verify contractor license: WA L&I Contractor Lookup
• Zoning information: View zoning info
• Columbia County Planning and Building
• Building Information and Resources
• Planning Applications and Information
• Columbia County Code Chapter 15.10
• Columbia County Public Health — Environmental Health (Septic/Well)
• L&I Electrical Permits and Inspections
• License lookup guide: Washington Contractor License Requirements
• Contract template: Washington Homeowner-Contractor Agreement
• Washington hub: Washington Contractor License & Permit Hub