Washington Plumbing License: What Applies and What Does Not
What Washington requires of a plumbing business in 2026, what the LLC has to file first, and where the license and the entity are two separate steps.
By Edmond Hui · Last updated: September 2026
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Washington plumbing licensing at a glance
| State credential required for this work? | Yes, statewide |
| What they are called | Journey Level Plumber (PL01), Residential Specialty Plumber (PL02), Pump and Irrigation Specialty Plumber (PL03), Domestic Well Specialty Plumber (PL03A), Residential Service Specialty Plumber (PL04), Plumber Trainee, Medical Gas Piping Installer |
| Who issues it | Washington State Department of Labor and Industries |
| Must the business itself be licensed? | Yes |
Does a plumbing business need a license in Washington?
Washington issues 7 license classes for plumbers.
Washington certifies individual plumbers statewide through Labor and Industries and separately registers the contracting business. Only Labor and Industries certified plumbers may perform plumbing work on someone else's property, and a property owner may perform plumbing work on property the owner holds.
The plumbing business itself must be licensed or registered, not only the people doing the work.
A business that bids, advertises or performs construction work registers with Labor and Industries as a general or specialty contractor, files a continuous contractor surety bond of $30,000 for a general contractor or $15,000 for a specialty contractor, and carries general liability insurance. Contractors working with plumbing carry additional education, examination and licensing requirements on top of that registration.
This records what Washington publishes, not a determination about your business. Scope, thresholds and local requirements are set by the issuing body, so confirm with them before you bid or file.
Source: Plumbers, Washington State Department of Labor and Industries. Verified 2026-09-03.
What the LLC has to do first
Several states license the plumbing company separately from the individual plumber, so the LLC and the license are two filings, not one.
The entity filing is separate from anything the license requires. In Washington it is made with the Washington Secretary of State. File directly with the state here. The order matters wherever the license is issued to the company rather than to a person: the entity has to exist before an application can name it.
Forming an LLC as a plumbing business in Washington covers the filing itself, step by step.
Insurance Washington plumbers are asked to show
Plumbing license and registration schemes commonly require proof of general liability cover, and water damage from a failed connection is the claim these policies are bought for.
We do not publish Washington premium figures for this trade, so nothing here is a quote. Our business insurance guide for plumbers covers what each policy does and does not pay for.
This guide is general information, not legal or tax advice, and reading it does not create an attorney-client relationship. It reports what each state licensing board publishes for this trade, with the sources this page cites. It cannot tell you whether your own work needs a licence: that turns on the scope of the job, the value of the contract, and the city or county you work in, which commonly adds its own registration on top of the state's. Confirm your own position with the board named on this page and with your local building or business licensing office before you bid or start work.
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Edmond Hui · Founder, MyStateLLC
Edmond Hui is a software engineer and serial entrepreneur based in New York who has founded multiple online businesses across e-commerce, media, and information publishing. Before transitioning into tech, he spent years as a commercial real estate professional closing deals totaling over 100,000 square feet, giving him firsthand experience with business formation and entity structuring. He built MyStateLLC to provide the free, state-specific LLC guidance he wished existed when forming his own companies.