How to become a plumber in Washington

The path in Washington, step by step

Washington licenses plumbing work at the state level through the Washington State Department of Labor and Industries (L&I), Plumber Certification Program. These are the steps it lays out, in order.

1. Get a plumber trainee certificate from L&I and work under a certified plumber.
2. Log your hours: at least 8,000 for journey level (PL01), with 4,000 on commercial or industrial work.
3. Apply to L&I for the exam, pass it, and get your certificate.
4. Buy a $6,000 surety bond and the required liability insurance, and set up workers' comp if you have employees.
5. Apply to L&I for the plumbing contractor license, naming the full-time certified plumber, and pay the $148.10 fee.
6. Renew the contractor license every 24 months and your certificate every three years with 24 hours of continuing education.

The full license guide, with every fee and form: plumbing license in Washington.

Finding an apprenticeship in Washington

Washington runs Registered Apprenticeship through its own State Apprenticeship Agency, recognized by the U.S. Department of Labor to register and oversee programs there. Its staff are state employees, and it may use the federal paperwork or forms of its own. Apprenticeship.gov lists the Washington State Apprenticeship Agency as the contact.

Either way, a registered program means paid work with a mentor, raises as you progress, classroom instruction and a credential recognized in every state. Search open spots in the Apprenticeship Job Finder.

Across the country. Most plumbers learn the trade in a 4 or 5 year apprenticeship, with about 2,000 hours of paid on-the-job training plus some classroom instruction each year.

License levels and exams in Washington

The license to aim for: Plumbing contractor license, plus a journey level (PL01) or specialty plumber certificate.

Trade exam. Yes. Journey level and specialty plumbers must pass an L&I certification exam. A state-authorized testing contractor normally gives the exam, and its fee is on top of the L&I fee.

Keeping it. The plumbing contractor license expires 24 months after it is issued. Plumber certificates renew every three years on your birthdate, with 24 hours of approved continuing education, including 4 hours on electrical safety.

Coming from another state. Washington has reciprocal certification with Idaho for journey level plumbers. Other out-of-state plumbers can present a comparable license, or equivalent U.S. military experience, for consideration.

What the Washington license costs

The fees the Washington State Department of Labor and Industries (L&I), Plumber Certification Program lists. Exam fees from a testing company, insurance and any bond come on top.

What plumbers earn in Washington

The median plumber in Washington earned $38.96 an hour in May 2025, 8th of 51 states, with 12,470 on payrolls. The national median was $30.67.

At the bottom of the range, a quarter of plumbers in Washington earned under $28.86 an hour and a tenth under $23.79. At the top, a quarter earned over $51.64 and a tenth over $68.20.

Every state, the neighbors and what a business should charge: plumber salary in Washington.

Jobs ahead in Washington

Washington's labor market office projects jobs for plumbers growing from 11,920 in 2022 to 13,120 in 2032, a change of 10.1%. Counting people who retire or change careers, that is about 1,320 openings a year.

Jobs are projected to grow 10.1% from 2022 to 2032, faster than the 2.3% projected nationally, ranking 18th of the 50 states in the file.

These are the state's own long-term projections, published together on Projections Central for the occupation group plumbers, pipefitters, and steamfitters.

Starting your own plumber business in Washington

To contract on your own in Washington, the license is the Plumbing contractor license, plus a journey level (PL01) or specialty plumber certificate.

Insurance. Liability insurance, or an assigned account, of $50,000 for property damage, $100,000 for injury or death to one person, and $200,000 for injury or death to more than one person. You also show workers' compensation coverage for employees working in Washington.

Bond. A $6,000 surety bond with the State of Washington named as obligee.

Pricing comes next. Paying yourself the Washington median of $38.96 an hour, the labor rate calculator's starting numbers (one person, 2 unbilled hours a day, $90,000 of overhead, 15% profit) come to $139.01 per billable hour. Try your own in the plumber labor rate calculator.

The full checklist is in how to start a plumbing business. The free Koira Office plan gives you a website on a Koira address, estimates customers sign with a deposit, invoices with card payments and your day's jobs in one place, with no per-person fee. See the plans.