Who licenses plumbers in Maryland?
The Maryland State Board of Plumbing licenses and regulates individuals who provide or assist in providing plumbing and gas services in Maryland. The Board also issues natural gas fitter licenses to qualified non-plumbers.
Both license types are required throughout Maryland except Baltimore County and the areas served by the Washington Suburban Sanitary Commission, or WSSC, in Prince George’s and Montgomery counties. Those two jurisdictions issue their own licenses and use their own plumbing codes.
For most state applicants, the plumbing ladder is Apprentice Plumber/Gas Fitter, Journey Plumber/Gas Fitter, and Master Plumber/Gas Fitter. Our broader plumbing license guide explains how apprenticeship, documented experience, testing, and local rules fit together across states.
Start with the job address
Maryland does not operate as one blanket plumbing jurisdiction. The State Board license covers the state except Baltimore County and WSSC territory, according to the Board overview.
Use this routing rule before filing anything:
- For work outside Baltimore County and WSSC territory, begin with the State Board.
- For work in Baltimore County, use the county plumbing program.
- For work in Prince George’s or Montgomery counties, check whether the address is in WSSC territory and use the WSSC licensing path when it is.
The work location decides the licensing office. It can also affect reciprocity: the State Board has defined reciprocal paths for qualifying Baltimore County and WSSC licensees, but that is not the same as statewide coverage.
Apprentice, journey, and master requirements
The Maryland license requirements set a sequential path. Apprentice Plumber/Gas Fitter applicants must be at least 16 years old.
A Journey Plumber/Gas Fitter applicant must have held an apprentice license for at least four years, completed 7,500 hours of training under the control and direction of a licensed master plumber, completed 32 hours of backflow prevention device testing training, and passed a comprehensive written examination.
A Master Plumber/Gas Fitter applicant must have held a journey license for at least two years, completed 3,750 hours of training under the direction and control of a licensed master plumber, and passed a comprehensive written examination.
The requirements page establishes eligibility for each tier. It does not replace the separate application and documentation steps, so read the Maryland requirements before scheduling the exam.
How the exam process works
Before applying for a Master Plumber/Gas Fitter, Master Natural Gas Fitter, Journeyman Plumber/Gas Fitter, or Journeyman Natural Gas Fitter license, an applicant must pass the PSI examination. The Board directs applicants to PSI to register and test.
PSI applicants must submit proof of hours worked, a copy of the backflow certification, and a copy of a driver’s license through the PSI client portal. That makes recordkeeping part of exam eligibility, not an afterthought.
Before registering, assemble a clean record of supervised hours and the backflow certificate. A qualifying work history is much easier to use when the supporting records are already organized.
Maryland plumbing license fees
The Maryland Forms and Fees page says it was updated July 1, 2025. Its listed fees are:
| Credential | Original license | Renewal |
|---|---|---|
| Master Natural Gas Fitter | $150.50 | $43.50 |
| Master Plumber/Gas Fitter | $87.50 | $87.50 |
| Journeyman Natural Gas Fitter | $68.50 | $31.50 |
| Journeyman Plumber/Gas Fitter | $43.50 | $43.50 |
| Apprentice Natural Gas Fitter | $18.50 | $18.50 |
| Apprentice Plumber/Gas Fitter | $18.50 | $18.50 |
The same page lists a $25 initial application fee and a $31.50 license fee for the Propane Gas Fitter certificate. It also says an Apprentice Natural Gas Fitter or Apprentice Plumber/Gas Fitter license may be renewed for only two consecutive cycles before the licensee must take the journey exam.
Treat the two-cycle rule as a planning deadline. The fee is small compared with losing time because your hours, training, or exam paperwork is not ready.
Which reciprocal paths does Maryland offer?
The Board may issue a reciprocal master or journey license to plumbers currently licensed in Baltimore County, WSSC, or the District of Columbia. For reciprocity from WSSC or Baltimore County, the applicant must hold both the plumbing and gas portions of the license, and the license must have been obtained by examination.
Maryland also reciprocates with Delaware for the Master Plumber/Gasfitter license only. The reciprocal licensing page lists the supporting records for Master or Journeyman Plumber/Gas Fitter applicants: a verification letter from the applicable jurisdiction, backflow certification, a current license copy, photo identification, and a certificate of insurance for master applicants.
This is a list of named reciprocal routes, not a general transfer of any out-of-state license. Our contractor license reciprocity guide explains why reciprocal agreements must be checked jurisdiction by jurisdiction.
Maryland plumbing license FAQ
Who licenses plumbers in Maryland? The Maryland State Board of Plumbing licenses plumbers and gas fitters for most of the state. Baltimore County and WSSC territory use separate licensing systems.
How do I become a Journey Plumber/Gas Fitter? Hold an apprentice license for at least four years, complete 7,500 hours under a licensed master plumber, complete 32 hours of backflow prevention device testing training, and pass the written examination.
How do I become a Master Plumber/Gas Fitter? Hold a journey license for at least two years, complete 3,750 hours under a licensed master plumber, and pass the written examination.
Which jurisdictions have reciprocal licensing paths with the Maryland State Board? The Board identifies paths for Baltimore County, WSSC, the District of Columbia, and Delaware. Delaware reciprocity applies only to the Master Plumber/Gasfitter license.