Plumbing Contractor Permit Requirements in Seattle, WA

Complete permit and license guide for starting a plumbing contractor in Seattle, King County, Washington.

$800 -- $2500 6–10 weeks to obtain all licenses and permits 6 requirements

Not legal advice. Requirements may change — always verify with your local government authority before applying. Last verified: .

Seattle / King County Requirements

2 requirements
1

City of Seattle Business License Tax Certificate

All businesses operating in Seattle must obtain a Business License Tax Certificate from the Seattle Office of Housing and Finance. The annual fee is based on total annual income. Plumbing contractors must list their Washington State contractor registration number.

$110/year (base fee for businesses under $20,000 revenue; higher for larger businesses)1–5 days (online application)
Official government source
2

Seattle Department of Construction and Inspections — Contractor Verification

Plumbing contractors must have their Washington State plumber license and contractor registration verified with the Seattle Department of Construction and Inspections (SDCI) before pulling permits. No separate city plumbing contractor exam is required; the state license and registration are sufficient.

No additional fee1–3 days
Official government source

Washington State Requirements

3 requirements
1

Washington State Contractor Registration

All contractors in Washington State must register with the Washington State Department of Labor and Industries (L&I). Contractor registration requires proof of general liability insurance ($50,000 minimum for specialty contractors), a $12,000 surety bond, and a unified business identifier (UBI) number from the Department of Revenue.

$113 biennial registration fee + $12,000 bond (~$100–$250/year premium)1–3 weeks
Official government source
2

Washington State Plumber License

Washington requires all plumbers performing work to hold a state Journeyman or Master Plumber license. The licensing qualifier for a plumbing contracting business must hold a state Plumbing Contractor License. Issued by the Washington State Department of Labor and Industries (L&I). Pass a state exam and have requisite experience.

$135 (biennial plumber license); $175 (contractor license)4–8 weeks
Official government source
3

Washington Business Entity Registration

LLCs and corporations must register with the Washington Secretary of State. Also register with the Department of Revenue for a Unified Business Identifier (UBI).

$180 (LLC filing fee) + $19 UBI registration2–5 business days
Official government source

Federal Requirements

1 requirement
1

EIN (Employer Identification Number)

Required if you have employees or operate as an LLC/corporation. Free from the IRS.

FreeImmediate (online application)
Official government source

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