Plumber Certifications (Which Ones Are Worth It)
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Plumbing is a licensed trade, so the credential that matters most is a government-issued license rather than a brand-name certificate. In most US states and many cities, you cannot legally work as a plumber, pull a permit, or supervise a job without holding the right license tier, and those tiers are earned in order: apprentice, then journeyman, then master. The path almost always runs through a registered apprenticeship that combines paid work hours with classroom instruction.
Below are the plumbing credentials worth pursuing, who each is for, and how to list them on your resume so they actually help. Because licensing is set by each state and sometimes by the county or city, the exact license names, hour requirements, and exams vary by jurisdiction; the national certifications listed here are add-ons that travel better and signal specialized skills.
Top certifications for a Plumber
State Master Plumber License
State or local plumbing licensing board (state-issued license, not a national certification) · Advanced
Best for: Experienced journeymen ready to run their own jobs, pull permits, and supervise other plumbers.
The top legal tier in most states; lets you contract, supervise, and bid larger work, and it is the credential employers and clients trust most.
State Journeyman Plumber License
State or local plumbing licensing board (state-issued license, not a national certification) · Intermediate
Best for: Plumbers who have completed an apprenticeship and passed the state journeyman exam.
The license that lets you work independently on most jobs; it is the core credential the majority of plumbing roles require.
Registered Plumbing Apprenticeship Completion (U.S. Department of Labor registered program)
U.S. Department of Labor Office of Apprenticeship and state apprenticeship agencies (often delivered via United Association (UA) locals and community colleges) · Entry
Best for: New plumbers building the on-the-job hours and classroom instruction needed to sit for the journeyman exam.
The standard, paid entry path; completion certificates are nationally recognized and count toward state licensing.
EPA Section 608 Technician Certification
U.S. Environmental Protection Agency (EPA), via approved certifying organizations · Entry to Intermediate
Best for: Plumbers who service, install, or dispose of equipment containing refrigerants, such as some water heaters and combined HVAC work.
Federally required to handle refrigerants; a low-cost credential that widens the jobs you can legally take.
Backflow Prevention Assembly Tester Certification
Issued through state or local programs and recognized training providers such as the American Society of Sanitary Engineering (ASSE International) and the American Backflow Prevention Association (ABPA) · Intermediate
Best for: Plumbers who test, repair, or certify backflow prevention assemblies on potable water systems.
A high-demand, recurring-revenue specialty that many jurisdictions require for cross-connection control work.
Medical Gas and Vacuum Systems Installer Certification (ASSE 6010)
American Society of Sanitary Engineering (ASSE International) · Advanced
Best for: Plumbers installing piping for medical gas and vacuum systems in hospitals and healthcare facilities.
Required for medical gas work to NFPA 99; a well-paid niche with limited qualified competition.
Green Plumber and Water Efficiency Training
Recognized industry programs such as IAPMO and the WaterSense labeling program from the U.S. EPA · Intermediate
Best for: Plumbers focused on high-efficiency fixtures, water conservation, and sustainable retrofits.
Signals current knowledge of efficient systems that residential and commercial clients increasingly request.
Gas Fitter or Gas Piping Certification
State or local licensing board (state-issued credential, where required) · Intermediate
Best for: Plumbers who install or service natural gas and propane piping and appliances.
Many jurisdictions require a separate gas credential; it lets you take on gas line and appliance work legally.
Water Heater Installation and Service Training
Manufacturer and industry training programs (for example through IAPMO and equipment manufacturers) · Entry to Intermediate
Best for: Plumbers specializing in tank and tankless water heater installation, code compliance, and service.
A steady, high-volume residential service line; manufacturer training also supports warranty work.
OSHA 10 or OSHA 30 Construction Safety Certification
U.S. Occupational Safety and Health Administration (OSHA), via authorized outreach trainers · Entry
Best for: Plumbers working on construction and commercial job sites that require documented safety training.
Often mandatory for site access; a quick, widely recognized credential that many general contractors require.
Plumbing Design Certification (Certified in Plumbing Design, CPD)
American Society of Plumbing Engineers (ASPE) · Advanced
Best for: Experienced plumbers moving into plumbing system design, estimating, or engineering support roles.
A recognized credential for the design side of plumbing; it opens higher-paying technical and office career paths.
How to choose the right plumber certification
Start with licensing, because it is the law, not a nice-to-have. Find your state or local plumbing board and confirm the exact ladder and hour requirements, then aim for the next tier up: apprentices work toward the journeyman exam, journeymen toward the master license. Almost everyone gets there through a registered apprenticeship, so if you are new, getting into a United Association (UA) local or a community college program with paid hours is the single best move you can make.
Once your license path is clear, add stackable certifications that match the work you want and pay more. EPA Section 608 is cheap and broadly useful, backflow testing and medical gas (ASSE 6010) are well-paid specialties that many areas require, and OSHA training is often needed just to get on a commercial site. Pick add-ons that your local market actually demands rather than collecting credentials, and remember that several of these, including backflow and medical gas, require periodic renewal.
How to list certifications on a plumber resume
Lead with your license and be specific. A line like "State Journeyman Plumber License, [State], #00000000, current through 2027" tells a hiring manager exactly what you can legally do, which is far more useful than "licensed plumber." For each credential, list the full name, the issuing board or organization, the state or jurisdiction where it applies, the license or certificate number, and the current expiration date.
Put licenses and certifications in a dedicated section near the top of the resume, ordered by relevance to the job you want, and note apprenticeship hours completed if you are not yet licensed. List in-progress items honestly as "in progress" with the expected date. Never claim a license tier you have not earned, since plumbing boards keep public verification databases and a false claim is easy to check and costly to lose an offer over.
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Frequently asked questions
Do you need a license to work as a plumber?
In almost every US state, yes. Plumbing is a licensed trade, and you generally must hold the right tier — apprentice, journeyman, or master — to work, pull permits, or supervise a job. The exact rules are set by your state and sometimes your county or city, so check your local plumbing board for the specific requirements.
Is a plumbing license the same as a certification?
Not quite. A plumbing license is a government-issued legal credential from a state or local board that authorizes you to do the work. National certifications such as EPA Section 608, backflow tester, or medical gas (ASSE 6010) are add-ons that prove specialized skills but do not replace your state license.
How do you become a licensed plumber?
The standard path is a registered apprenticeship that combines paid on-the-job hours with classroom instruction, often through a United Association (UA) local or a community college. After completing the required hours you sit for your state journeyman exam, then gain experience and pass the master exam to reach the top tier.
Which plumbing certifications pay the most?
Beyond the master license itself, specialized add-ons tend to pay best. Medical gas and vacuum systems work under ASSE 6010, backflow prevention testing, and moving into plumbing design with the ASPE Certified in Plumbing Design (CPD) credential are well compensated because they require extra training and are in steady demand.
