Plumbing License in Washington: Fees, Requirements & Startup Costs

By Muhammet Çay

Quick answer: A Washington PL01 is an individual journey-level plumber certificate, not the business plumbing contractor license. PL01 covers all phases of plumbing construction; PL02 is a residential specialty. A business contracting for plumbing also needs its own L&I contractor license and a designated certified plumber within the permitted scope. See L&I certification categories and business licensing requirements.

Source check: October 23, 2026. PL01/PL02/PL04 scope and experience, the posted contractor application steps and WAC fee entries were checked. This is a licensing-source review, not individual licensing advice. Original publication and other data-record dates are retained.

Two licenses, two roles

Washington splits plumbing authority between a business credential and an individual credential. The Plumbing Contractor license belongs to the business and is what allows the company to advertise, bid, offer, or perform plumbing. Since July 2021, that license has been required for those activities, and the business must designate an L&I certified plumber. The certified plumber is the individual qualifier who carries the trade credentials; the contractor license is the entity-level authority. A company cannot contract for plumbing on the strength of a certified plumber alone, and a certified plumber cannot contract through a business that holds no contractor license.

The L&I plumbing contractor page describes the contractor license as the business license to contract for plumbing. Plan the two applications together, because the contractor license depends on the designated plumber being in place.

PL01 vs PL02 vs PL04: which certificate covers the work?

Individual certificate	Work scope	Experience before application
PL01 journey level	All phases of plumbing construction	At least 8,000 supervised trainee hours over four or more years, including at least 4,000 commercial or industrial hours
PL02 residential	Single-family homes, duplexes and apartment buildings no more than three stories	At least 6,000 hours in the specialty over three or more years under an appropriately certified plumber
PL04 residential service	Limited existing-system service in single-family homes and duplexes, plus the specific drain-cleaning/leak-repair work listed by L&I	At least 4,000 trainee hours over two or more years; the first 2,000 or more under direct journey-level or residential-specialty supervision

Source: L&I plumber certification requirements. Read the full restrictions before selecting a specialty. A certificate does not itself authorize an unlicensed business to advertise or contract; the business needs the separate contractor credential. The broadest category is not automatically the right path for every proposed service.

Licensing in Washington

Jurisdiction: state

Authority: Washington Department of Labor & Industries (L&I), Plumbing Program

Since July 2021, a plumbing contractor license is required to advertise, bid, offer, or perform plumbing; the business must designate an L&I certified plumber.

Plumbing Contractor

BUSINESS Business license to contract for plumbing; requires designated certified plumber, $6,000 surety bond or savings assignment, and $250,000 liability insurance.

Fee	Amount	Period (years)
Initial plumbing contractor license	$148.10 OFFICIAL FEE Source — app.leg.wa.gov	2
Initial designated plumber identification	$53.20 OFFICIAL FEE Source — app.leg.wa.gov	—
Plumbing contractor license renewal	$148.10 OFFICIAL FEE Source — app.leg.wa.gov	2

Exam: Not listed here

Bond: $6,000 OFFICIAL FEE Source — lni.wa.gov

Insurance: Requirement: $250,000 liability insurance · Source

Renewal and CE: Renewal period: 2 years · Source

Journey Level Plumber (PL01)

INDIVIDUAL Certified plumber qualified for all phases of plumbing construction; can serve as contractor's designated plumber.

Fee	Amount	Period (years)
L&I journey-level plumber examination application; testing contractor may charge an additional exam administration fee	$202.10 OFFICIAL FEE Source — lni.wa.gov	—
Initial journey-level plumber certification after passing exam	$242.70 OFFICIAL FEE Source — lni.wa.gov	3
Journey-level plumber certification renewal	$242.70 OFFICIAL FEE Source — lni.wa.gov	3

Exam: Provider: L&I / state-authorized testing contractor · Fee: 202.1 · Source

Experience: At least 8,000 supervised trainee hours over four years, including at least 4,000 commercial or industrial hours.

Renewal and CE: Renewal period: 3 years · Continuing education: 24 hours · Source

Local note: Check local plumbing permit and inspection requirements.

Data notes

The testing vendor may charge an additional administration fee. Residential specialty PL02 and residential service PL04 offer narrower qualifier options.

Verified: 2026-09-25

Exam and experience for the qualifier

The Journey Level Plumber path requires at least 8,000 supervised trainee hours over four years, including at least 4,000 commercial or industrial hours. After the experience requirement is met, the applicant applies for the L&I journey-level plumber examination. The exam application fee is $202.10, and the state-authorized testing contractor may charge an additional exam administration fee; the exact current amount is not listed in the sources reviewed for this page. After passing, initial journey-level certification costs $242.70 and runs for three years.

The contractor license application itself has no exam listed in the official sources reviewed for this page. The trade testing sits with the individual qualifier, not with the business entity.

Bond and insurance

The Plumbing Contractor license requires a $6,000 surety bond or an assigned savings account, plus $250,000 in liability insurance. Both are conditions of the contractor license, and both are separate from the license fees. Obtain the bond and the insurance certificate before expecting the contractor license to be issued, and keep the coverage active for as long as the license is in use. The official sources reviewed for this page do not list a bond or insurance requirement for the individual plumber certification.

Renewal and continuing education

The plumbing contractor license renews every two years at $148.10, the same amount as the initial issuance. The journey-level plumber certification renews every three years at $242.70 and requires 24 hours of continuing education. Renewal fees are not part of the year-one starting cost; they come due later, but they belong on the operating calendar so a job does not outlast the authority to perform it. A change in designated plumber costs $53.20, so a staffing change at the qualifier level has its own fee.

Local permits and inspections

Washington cities and counties handle plumbing permits and inspections. A state contractor license does not set local permit policy. For each job address, ask the local building department which work needs a permit, who must apply, and how inspections are scheduled. Add permit time and inspection returns to the estimate. The plumbing business guide covers the operating side of a new shop, and the startup costs page explains how bond, insurance, and tool purchases move the opening budget.

Startup Cost Calculator

TradeStateLicense class/pathStructureEmployeesVehicleVehicle paymentTools already owned (%)Tool kit levelSoftware tierMonthly marketing budgetMarketing launch monthsWorking-capital monthsBusiness miles per monthMonthly phone and adminPermits and complianceAverage ticket (default — replace with your number)Gross margin % (default — replace with your number)

Estimated startup cost: $9,100–$11,200

Estimated startup cost: $9,100–$11,200. Break-even at about 7 jobs per month.

Licensing & exam fees	$201.30 OFFICIALLicense details
Business formation (state filing)	$180 OFFICIAL
Insurance (first year)	$1,750 MARKET ESTIMATEGeneral liability Coverage sources General Liability: Insureon Workers Comp: Insureon Commercial Auto: Insureon
Vehicle acquisition	$0 YOUR INPUTYour existing vehicle; acquisition cost $0 Vehicle price sources 2026 Ram ProMaster cargo van (base): $45,300 2026 Ford F-150 XL (base): $40,100 2026 Ford Transit-150 cargo van (base, T-150 130in low roof RWD): $48,400 Used vehicle average listing price (all segments, not cargo-van specific): $27,200
Tools & equipment	$50 MARKET ESTIMATE Starter kit items Pipe wrenches: $40 Tubing cutter: $50 Drain auger: $50 Ladder: $330 Safety gear: $10 Milwaukee M18 FORCE LOGIC 2922-20 press tool (ONE-KEY): $2,250 Milwaukee 2773-22L M18 Force Logic long throw press tool kit 1/2-1 in.: $4,550 RIDGID K-400 drum drain cleaning machine: $830 Inspection camera: $40
Software (first year)	$590–$2,250 MARKET ESTIMATEPublished monthly list price × 12 Software price sources Jobber core: $50/month Jobber connect: $140/month Jobber grow: $200/month Jobber plus: $500/month Housecall Pro basic: $80/month Housecall Pro essentials: $190/month Housecall Pro max: $330/month QuickBooks Online simple start: $40/month QuickBooks Online essentials: $90/month QuickBooks Online plus: $140/month QuickBooks Online advanced: $340/month
Launch marketing	$1,500 YOUR INPUTYour input — default: 3 months × $500
Payroll reserve	$0 CALCULATEDBLS median wage × 173 hours/month × employees × employer taxes and ECEC benefits × working-capital months
Working capital	$4,800–$5,250 CALCULATEDMonthly overhead excluding payroll (shown separately) × working-capital months
Permits & compliance	$0 YOUR INPUTYour input — default $0; local requirements may apply

Monthly overhead: $1,600–$1,750 · Annual operating: $19,300–$21,000 · Break-even: 7 jobs/month

Vehicle operating per month: $760 CALCULATED

Phone and admin per month: $150 YOUR INPUT

Show formula

Startup total is the sum of available first-year cost lines. Monthly overhead includes insurance, software, marketing, vehicle operating, phone and admin, and payroll. Break-even jobs = monthly overhead ÷ (average ticket × gross margin).

For a side-by-side view of credentials in other states, see the plumbing license requirements by state, including California and Arizona.

Frequently asked questions

What is a PL01 license in Washington?

PL01 is the individual journey-level plumber certificate covering all phases of plumbing construction. A business also needs its separate plumbing contractor license and a designated certified plumber.

How is PL02 different from PL01?

PL02 is limited to plumbing in single-family homes, duplexes and apartment buildings no more than three stories; PL01 has the broader journey-level scope. L&I lists separate experience requirements.

What does the PL01 experience requirement include?

At least 8,000 supervised trainee hours over four or more years, including at least 4,000 commercial or industrial hours.

Which business fees are listed by Washington?

The WAC lists $148.10 for the contractor credential and $53.20 for initial identification or a change of designated plumber. Individual exam and certification fees are separate; bond and insurance are not license fees.

Last updated: October 23, 2026