Plumbing Contractor License in Maryland: Requirements, Qualifier, Bond and Exams

Statewide — but the licenses on the board's list belong to individuals, not companies.

The Maryland State Board of Plumbing licenses individuals as Apprentice, Journey and Master Plumber/Gas Fitter statewide.

What our research did not find is a separate plumbing contractor or company license: the board's license list holds only individual licenses, and a plumbing business operates under an individually licensed, insured Master Plumber/Gas Fitter.

That reading comes from the board's own license list rather than a statute we read, so confirm it with the board before you set up the business.

There is also a local layer — the board may issue reciprocal licenses to plumbers licensed by examination in Baltimore County, WSSC or DC, which tells you those jurisdictions license plumbers under arrangements of their own.

The Maryland State Board of Plumbing issues the licenses.

Its plumbing classes are Apprentice, Journey and Master Plumber/Gas Fitter, and the same board licenses a separate natural gas fitter family — Apprentice, Journey and Master Natural Gas Fitter — plus a Propane Gas Fitter certification based on NPGA Distribution Systems Operations training or its equivalent.

There is no contractor class on the list we read: the license a plumbing business operates under is its qualifier's own Master Plumber/Gas Fitter license.

For firms planning gas work, note the separate family's rung: a Journey Natural Gas Fitter license takes 3,750 working hours as an apprentice natural gas fitter over at least 2 years.

Our research found no separate company qualifier form or rule: the qualifier is whichever person's Master Plumber/Gas Fitter license the business operates under, and that master license is the credential the arrangement rests on.

To hold it, an applicant must have held a journey license for at least 2 years, completed 3,750 hours under a licensed master plumber, and passed a comprehensive written exam.

The journey license beneath it takes at least 4 years as a licensed apprentice, 7,500 hours of training under a licensed master plumber, 32 hours of backflow prevention device testing training, and a written exam.

Apprentices must be at least 16, and an apprentice license can be renewed for only two consecutive cycles before the holder must take the journey exam — so the qualifier's ladder starts years before the business does.

The detailed apprentice and journey rules live in our Maryland plumbing license guide for individuals.

PSI Examination Services provides all testing for the State Board of Plumbing.

The master Plumber/Gas Fitter exam is a comprehensive written exam, and the journey exam beneath it is written as well.

Candidates upload proof of their hours, backflow certification and identification to PSI — that is where the experience documentation meets the exam booking.

Our research did not find a separate business-and-law exam for Maryland plumbing businesses: the board pages we read name the trade exams, not a business test.

That is an absence in our reading rather than a board statement, so confirm the current exam lineup with the board before you schedule study time.

No bond appears in the board pages we read: our research found no Maryland plumbing contractor bond, and the requirement on record is insurance.

A Maryland master plumber must carry at least $400,000 per occurrence — $300,000 general liability plus $100,000 property damage — and the board accepts no umbrella policies toward it.

The certificate names the Maryland State Board of Plumbing as certificate holder and must show the individual licensee's name and number; the board's reciprocity page describes the insurance certificate as a master-applicant requirement.

The requirement falls on the master licensee, so treat it as an obligation that follows the person the business operates under.

HVACHires' guide to contractor license bonds and insurance explains how license bonds differ from liability insurance and gathers state-by-state amounts.

The master license on the board's individual-only list costs $87.50 to apply, and renewals run the same $87.50, on the board's fee schedule as updated July 1, 2025.

The rungs beneath it are $43.50 for the journey license and $18.50 for the apprentice license; the separate gas fitter family is pricier, at $150.50 for the original Master Natural Gas Fitter license and $68.50 for the journey level.

Every State Board of Plumbing license and certificate expires two years from its date of issue, so a license's renewal date follows its issue date.

Continuing education is not part of the plumbing renewal — the board's continuing-education requirement of 8 hours a year applies to plumbing inspectors only, not to plumbers.

The reciprocity on record is local jurisdictions plus one state.

The board may issue a reciprocal master or journey license to plumbers who are currently licensed in Baltimore County, WSSC or DC — holders licensed by examination there — and it reciprocates with Delaware for the Master Plumber/Gas Fitter license only.

The fine print matters for a business: Baltimore County and WSSC licensees must hold both the plumbing and gas portions obtained by examination.

Beyond Delaware, our research found no other state agreements, so a master licensed in another state should plan to qualify through Maryland's own experience and exam requirements.

This is a gap in our research, not a settled rule: we did not find a Maryland board rule setting a deadline to replace the master whose license the business operates under, or a notification requirement.

On our reading of the board's license list, the arrangement rests on an individual's Master Plumber/Gas Fitter license, and our research found no company license to fall back on — while the insurance obligation itself is on record: Maryland master plumbers must carry $400,000 per occurrence.

Every board license expires two years from its date of issue, so a replacement master arrives on a license with its own renewal clock.

Ask the Maryland State Board of Plumbing what a business may and may not do while it lines up a new licensed master, and read HVACHires' qualifying agent guide for how the qualifier arrangement works in the trades.

The confirmed piece is the board's own reciprocal arrangement: it may issue reciprocal master or journey licenses to plumbers licensed by examination in Baltimore County, WSSC or DC, which tells you those jurisdictions run licensing of their own.

What that means for a plumbing business working in the WSSC area — the Washington Suburban Sanitary Commission, serving Montgomery and Prince George's counties — was not captured: the WSSC page did not load during our research, so we record the WSSC business requirements as unverified rather than guessing them.

Baltimore County and WSSC licensees who reciprocate into Maryland must hold both the plumbing and gas portions obtained by examination.

Before you bid work in those jurisdictions, ask WSSC and Baltimore County what they require of the business itself.