🚰 License & Certification

Plumbing License & Certification Exam Prep

Plumbing is a licensed trade with specialty certifications layered on top. This overview covers the journeyman → master → contractor license ladder, plus medical-gas, backflow-tester and plumbing-design credentials.

⚠️ Requirements, fees and exam details vary by state, jurisdiction and over time. Always confirm the current specifics with ASSE International, ASPE or the relevant board before you apply.
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The credential landscape

Plumbers progress through a state license ladder — apprentice → journeyman → master → contractor — based on documented experience and code-based exams. Specialties such as medical-gas installation, backflow-prevention testing, and plumbing design (CPD) or a Mechanical PE add scope for specific work.

Trade license path
  1. 1Enter a plumbing apprenticeship (~4–5 years)
  2. 2Pass the Journeyman Plumber exam
  3. 3Gain journeyman experience
  4. 4Pass the Master Plumber exam
  5. 5Add a Plumbing Contractor license to run a business
Specialty / design path
  1. 1Hold a plumbing license
  2. 2Add Backflow Prevention Tester certification
  3. 3Add Medical Gas installer/inspector certification
  4. 4Pursue CPD (plumbing design) or a Mechanical PE
  5. 5Specialize (medical gas, hydronics, fire)
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Trade licensing

Journeyman Plumber License

PREP COMING SOON

The core working-plumber license to install and repair plumbing systems.

Administered by
State / local board (often via PSI/Prometric)
Format
Computer-based · open-book · ~80–100 questions
References allowed
Open-book — adopted plumbing code (UPC/IPC) and state amendments
How you qualify
Typically ~4–5 years / ~7,500–8,000 hours of documented apprenticeship plus classroom instruction. Varies by state.
Key topics
Plumbing code (UPC/IPC)DWV & ventingWater supply & sizingFixturesGas pipingBackflow basics

Master Plumber License

PREP COMING SOON

Advanced license to design installations and supervise journeymen.

Administered by
State / local board (often via PSI/Prometric)
Format
Computer-based · open-book · ~90–110 questions
References allowed
Open-book — plumbing code and state amendments
How you qualify
Several years of licensed journeyman experience; varies by state. Some add business/law.
Key topics
Advanced code applicationSystem design & sizingPlan reviewCross-connection controlSupervisionBusiness/law (some states)

Plumbing Contractor License

PREP COMING SOON

License to operate a plumbing business, pull permits and bid work.

Administered by
State contractor board
Format
Computer-based · trade plus business & law in many states
References allowed
Open-book code; business/law portion varies
How you qualify
Commonly requires a master license (or qualifier), experience, insurance/bonding, and a business & law exam.
Key topics
Code & tradeEstimating & project managementBusiness lawContracts & liensSafety & laborInsurance & bonding
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Specialty & design credentials

Medical Gas Installer / Inspector (ASSE 6010 / 6020)

PREP COMING SOON

Certification to install or inspect medical gas and vacuum systems.

Administered by
ASSE International (NITC-aligned)
Format
Written + brazing/practical (installer)
References allowed
Study NFPA 99 and ASSE 6000-series
How you qualify
Hold a plumbing/pipefitting background; complete approved training; brazing qualification for installers.
Key topics
NFPA 99Medical gas pipingBrazingSystem verificationZone valves & alarmsPurity testing

Backflow Prevention Assembly Tester (ASSE 5110)

PREP COMING SOON

Certification to test and certify backflow-prevention assemblies.

Administered by
ASSE International / state programs
Format
Written + hands-on practical (test assemblies)
References allowed
Study cross-connection control manuals (USC/ASSE)
How you qualify
Approved training course; pass written and practical exams. Often required for utility test programs.
Key topics
Cross-connection controlAssembly types (RP/DC/PVB)Test proceduresGauge useHazard assessment

Certified in Plumbing Design (CPD) / PE Mechanical

PREP COMING SOON

Design credentials for engineers and designers of plumbing systems.

Administered by
ASPE (CPD) / NCEES (PE)
Format
Computer-based exams
References allowed
CPD: ASPE references; PE: NCEES reference
How you qualify
CPD: plumbing-design experience and the ASPE exam. PE: FE + ~4 years + the PE Mechanical exam.
Key topics
Water supply & drainage designFixture units & sizingStorm drainageGas & special systemsCodes & standards
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Requirements at a glance

CredentialPrerequisiteTypical experienceAdministered by
Journeyman PlumberApprenticeship~4–5 years*State / local board
Master PlumberJourneyman licenseSeveral years*State / local board
Plumbing ContractorMaster (often)Experience + business*State board
Medical Gas (ASSE 6010)Piping backgroundTraining + brazing*ASSE
Backflow Tester (ASSE 5110)Approved courseWritten + practical*ASSE / state

* Experience hours and prerequisites vary significantly by state, jurisdiction and credential level. Figures shown are typical ranges, not legal requirements.

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Exam strategies & study tips

Tab your plumbing code

Journeyman and master exams are open-book and time-pressured. A well-tabbed UPC or IPC (whichever your state adopts) — sizing tables, venting, fixture units — is the biggest time-saver.

Master sizing calculations

Water-supply and DWV sizing, fixture-unit counts, and gas-pipe sizing recur. Drill them — and rehearse with the studio’s tools.

Plan specialty brazing/practical exams

Medical-gas and backflow certifications include hands-on practicals (brazing, assembly testing). Build the manual skills, not just the written knowledge.

Map the requirements before you study

Confirm the exact education, experience hours and application steps with the certifying body or state board first — missing a prerequisite trips up more people than the exam content does.

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Practice with the studio's free tools

Many exam questions are calculation problems you can rehearse right now with the free tools in the Plumbing Systems Studio:

Backflow Preventer Selection →Grease Interceptor Sizing →
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