Washington Plumbing Business Registration — Secretary of State, DOR, and L&I

Most plumbers who decide to start their own business know they need a contractor license from L&I. What catches them off guard is the two other registrations that must happen first — with the Secretary of State and the Department of Revenue — before L&I will even process their plumbing contractor application.

Step 1: Secretary of State — Business Entity Registration

Before anything else, register your business entity with the Washington Secretary of State. This creates the legal structure — sole proprietorship, LLC, corporation, or partnership. The Department of Revenue registration then provides your UBI (Unified Business Identifier) number.

The UBI is Washington's universal business ID. It follows your business across every state agency — L&I, Department of Revenue, Employment Security Department — so you use the same number everywhere.

For most new plumbing businesses, an LLC is the standard choice. The filing fee is $200 for an LLC ($180 online), and processing typically takes one to two weeks. You can file through the Secretary of State's Corporations & Charities Filing System online.

Step 2: Department of Revenue — Tax Registration

After your business entity exists, register with the Washington Department of Revenue (DOR) to set up your tax accounts. Washington has no state income tax, but plumbing contractors are subject to the Business & Occupation (B&O) tax and must collect sales tax on certain services.

DOR registration is done through Washington's Business Licensing Service (BLS) portal. The DOR registration activates your sales tax and B&O tax accounts and determines your reporting schedule (monthly, quarterly, or annually based on projected revenue).

Step 3: L&I — Plumbing Contractor Registration

With your UBI in hand, you can now file for the plumbing contractor registration with L&I. This requires:

• Completed Application for Plumbing Contractor License (Form F627-051-000)
• $6,000 continuous plumbing contractor surety bond
• General liability insurance ($250,000 combined single limit) verified through EBIPS
• Designated plumber assignment (Form F627-052-000, $53.20 fee)
• Workers' compensation account if you will have employees
• $148.10 contractor licensing fee

L&I will not process the application without the bond and insurance already in place. The designated plumber form requires notarized signatures from both the contractor representative and the designated plumber.

The Order Matters

Filing out of sequence creates delays. L&I requires your UBI number on the contractor application. DOR requires your entity to exist. And your bonding company will need your business name and structure before issuing the plumbing bond. The correct sequence is: entity first, DOR second, bond and insurance third, then L&I contractor registration.

For a step-by-step walkthrough of all three registrations with the specific forms, fees, and portal links, the Washington Plumber License Guide covers the full business setup process from entity formation through first permit.

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