Washington contractor licenses: one registration for contractors, separate licenses for electrical, plumbing and pesticides

Washington takes a different route from most states. It does not give contractors a state license by exam. It registers them. Anyone in the construction business signs up with L&I, posts a bond, carries insurance and pays a fee. The real exams come in the electrical and plumbing trades, and in pesticide work. This page lays out who handles what. The details change, so confirm with each agency, and treat this as general information rather than legal advice. Our Washington startup page covers business formation and taxes.

What does L&I contractor registration require?

L&I states that Washington requires all construction contractors to register, and that includes constructing, remodeling, repairing and demolishing buildings, roads and other real property. The statute reaches further than the word "construction" suggests. RCW 18.27.010 lists installing carpeting or other floor covering, erecting scaffolding, installing or repairing roofing or siding, performing tree removal services, and cabinet or similar installation inside the contractor definition.

L&I says it regulates 63 specialties, and the list includes roofing, painting, HVAC and tree removal. An assigned bank account can stand in for the bond. The bond and insurance must use your exact business name, and L&I must be listed as certificate holder on the liability policy. You also need a Washington business license from the Department of Revenue before you apply.

Notice what is missing: no trade exam and no required years of experience on L&I's registration page. That is why Washington's per-trade conversation moves quickly to electrical and plumbing, where L&I's own pages describe additional education, examination and licensing.

What happens to unregistered contractors?

L&I tells contractors that when they advertise, solicit bids or offer to perform work, they must always include the registration number. The law backs that up with penalties that bite on your wallet and your ability to collect:

• Infractions. RCW 18.27.200 makes it an infraction to advertise, offer, bid or perform contracting work without registration, to let an unregistered contractor work under your registration, or to subcontract to an unregistered contractor. Each day and each worksite is a separate infraction.
• Gross misdemeanors. RCW 18.27.020 makes the same conduct a gross misdemeanor, and using a false or expired registration number when buying an ad is one too. After a department citation, each day of unregistered work and each worksite counts as a separate gross misdemeanor.
• No suit for payment. RCW 18.27.080 bars a contractor from bringing or maintaining a court action to collect compensation without proving registration at the time of the contract, though a court can accept substantial compliance if L&I has your registration information on file and you kept the required bond and insurance continuously.
• Burden of proof. Under RCW 18.27.310, when an infraction is issued against an unregistered contractor, the contractor carries the burden of showing they were registered or exempt.

The subcontractor rule matters to a crew that hires help. Before you bring in a painter or a tree crew, check their status in L&I's lookup.

Who is exempt, and what is not on the list?

RCW 18.27.090 lists the exemptions. The ones an owner of a small service business is most likely to ask about:

• Projects totaling under $500, described as casual, minor or inconsequential. The exemption does not cover work that is part of a larger project, split up to evade the chapter, or advertised as contracting.
• Owners working on their own property or personal residence, unless they do contractor work to sell, demolish or lease it.
• Employees of a registered contractor whose wages are their only compensation.
• Certified electricians and plumbers working within their certification, and licensed architects and engineers within their professional role.

L&I's consumer publication F625-084-000 adds a plain-language list of services that do not require registration: gutter cleaning, pruning or lawn care, and window washing. It separately lists work that adds to or subtracts from real estate, and advice or consulting on a construction project, as requiring registration. For anything between those lines, such as pressure washing a deck or hauling out demolition debris, L&I says to email ContReg@Lni.wa.gov or call 1-800-647-0982 before you assume.

How does electrical licensing work?

Electrical is licensed separately and heavily. Under RCW 19.28.041 it is unlawful to advertise, offer to do work, bid or carry on the business of installing or maintaining electric wiring or equipment without an electrical contractor license. The license expires after 24 months, requires a $4,000 bond (or cash deposit), and requires you to designate an administrator who holds a master journeyman certificate, a master specialty certificate, or an administrator's certificate earned by exam.

Under RCW 19.28.161, individuals need one of four certificates: master journeyman electrician, journeyman electrician, master specialty electrician or specialty electrician. The statute names specialty electrician types including residential, pump and irrigation, limited energy system, signs, nonresidential maintenance, restricted nonresidential maintenance and appliance repair. If you hire a helper, plan for the trainee tier rather than assuming anyone can pull wire. For the national shape of this path, see how to become a licensed electrician.

How does plumbing certification work?

L&I states that only L&I-certified plumbers can legally perform plumbing work on someone else's property, and property owners may do plumbing on property they own. RCW 18.106.020 lists the certificates: journeyman, specialty, residential service, temporary and trainee, with a medical gas piping installer endorsement for that work. Trainees work under supervision, and L&I audits that supervision. RCW 18.106.020 says that after January 1, 2021 a plumbing contractor must be a licensed plumbing contractor under chapter 18.106, not just a registered contractor, and L&I describes its new plumbing licensing requirements as taking effect July 1, 2021, so confirm the current rule with L&I. Violations are infractions, and each day and each worksite where the violation occurs counts separately. Registered contractors cannot subcontract the work to uncertified people. The national plumber licensing guide gives context.

Who licenses lawn, pest and inspection work?

Three agencies handle what the Department of Labor & Industries does not.

• Pesticides (WSDA). Applying pesticides on someone else's property requires the Commercial Applicator License, a joint company and person license held by the person who makes the application decisions. WSDA lists it at $250 plus $27 for each piece of power application equipment after the first, with testing fees of $25 per session for paper exams or $58 per exam on a computer. Employees who apply need a Commercial Operator license at $85, valid only while working for a licensed company. WSDA reciprocates with some state and federal licenses, so testing may not be necessary. The national pest control license guide compares states.
• Wood destroying organism inspections (WSDA). A Structural Pest Inspector license, listed at $85, is required for a complete WDO inspection done for a transfer, exchange or refinancing of a structure. Full home inspectors need it only if they include WDO findings.
• Home inspectors (Department of Licensing). New inspectors complete 120 clock hours of Fundamentals of Home Inspection and 40 hours of field training, then pass the full exam. Inspectors licensed in good standing for at least 2 of the last 4 years in a state with comparable requirements can take only the state portion of the exam.

Who can design and install septic systems?

Under RCW 18.210 and chapter 246-272A WAC, on-site sewage systems are designed by licensed professional engineers or licensed on-site wastewater treatment system designers. Installers, pumpers and maintenance service providers must get approval from the local health officer before they provide services, per WAC 246-272A-0340. The rule required each local health officer to set approval procedures by February 1, 2025, so the paperwork differs from county to county. Check with the local health jurisdiction where the property sits.

What do you still owe if your trade is not licensed?

Registration exemptions do not remove tax duties. The Department of Revenue lists retail services that carry sales tax, including repairing or improving real property for consumers, construction, installing, cleaning or repairing tangible personal property, and landscaping and lawn maintenance. The state rate is 6.5% plus a local rate based on where the customer receives the service. You report sales tax and business and occupation tax on one excise tax return, and the account comes with your state business license. Many cities and counties require an endorsement on that license, added through the Business Licensing Service, and they issue their own permits. A lawn crew that needs no L&I registration can still owe sales tax on every invoice.

What this means for how you present your business

L&I says the number belongs in your advertising, bids and offers to perform work, so build it into estimates, ads and your site. A website that lists your registration number and specialty is easy to keep correct in one place, and an AI receptionist can read the same number back to callers who ask. To compare against other states, open the board-by-board comparison.

Frequently asked questions