Quick answer: a plumbing license in Maryland is a statewide credential issued by the Maryland State Board of Plumbing. You work your way up apprentice to journey to master, you pass a PSI exam before you apply, and masters have to carry a specific amount of insurance with the Board named as certificate holder.
Who licenses plumbers in Maryland
The Maryland State Board of Plumbing, part of the Maryland Department of Labor. One board, one license, good across the state. A few local programs run alongside it (Baltimore County and WSSC have reciprocal arrangements), and Delaware reciprocates at the master level.
The license tiers
- Apprentice Plumber. Registration, minimum age 16. Renewable for only two consecutive cycles, so it is a stepping stone, not a permanent status.
- Journey Plumber. The working license.
- Master Plumber. Lets you contract and pull permits.
- Natural Gas Fitter credentials (apprentice, journey and master) and a Propane Gas Fitter certification.
- Plumbing Inspector certification.
Hours and experience
- Journey Plumber: at least 4 years as an apprentice and 7,500 hours of work under a licensed master plumber, plus 32 hours of backflow prevention training, then the written exam.
- Master Plumber: at least 2 years as a licensed journey plumber and 3,750 hours, then the written exam.
- Journey Natural Gas Fitter: 3,750 hours over at least 2 years.
- Plumbing Inspector: a current master or journey license plus 4 years of experience and a Board exam. Note that your master license goes inactive while you hold the inspector card.
The exam
Maryland uses PSI testing centers, with sites in Baltimore, College Park, Hagerstown, Lanham and Salisbury. Two things trip people up here:
- You must pass the exam before you submit your license application. It is not the other way around.
- Once you pass, you have one year to apply. Miss that window and you retake it.
The Board does not publish a passing score, so treat the exam as pass or fail and study the adopted plumbing code cover to cover.
Fees
Current as of the July 1, 2025 fee update. Each line is application fee plus license fee:
- Master Plumber: $87.50 + $87.50
- Journey Plumber: $43.50 + $43.50
- Apprentice: $18.50 + $18.50
- Master Natural Gas Fitter: $150.50 + $43.50
- Journey Natural Gas Fitter: $68.50 + $31.50
Insurance
This is the requirement that catches new contractors. Maryland requires at least $400,000 per occurrence, made up of $300,000 general liability and $100,000 property damage. An umbrella policy stacked on top of a smaller primary policy is not accepted. The certificate holder must be the Board itself, not your company. Tell your agent that up front or the certificate comes back wrong.
Renewal and continuing education
Licenses renew on a two-year cycle from the issue date. There is no continuing education requirement for plumbers in Maryland. The only CE in the program is 8 hours per calendar year for the plumbing inspector ID card.
Let a license sit expired for 4 years or more and you start over: new application and a retake of the exam.
Reciprocity
Maryland runs reciprocal programs with Baltimore County and WSSC (the Washington Suburban Sanitary Commission), and with Delaware at the Master level only. Anything beyond that, verify with the Board before you count on it.
How to get licensed in Maryland, step by step
- Register as an apprentice. Get on the books at 16 or older and start logging hours under a licensed master.
- Log 7,500 hours over at least 4 years and finish the 32-hour backflow training.
- Schedule and pass the PSI journey exam.
- Apply within one year of passing, with your fees.
- Work 2 years and 3,750 hours as a journey plumber, then sit the master exam.
- Line up the insurance at $300k GL plus $100k property damage, with the Board as certificate holder, and apply for your master license.
FAQ
Does Maryland have a statewide plumbing license? Yes. The Maryland State Board of Plumbing issues it and it works across the state.
How many hours to become a journey plumber in Maryland? 7,500 hours over at least 4 years as an apprentice under a licensed master, plus 32 hours of backflow training.
Do I take the exam before or after applying? Before. You must pass first, then apply within one year.
Is continuing education required? Not for plumbers. Only the plumbing inspector ID card carries a CE requirement (8 hours per calendar year).
Requirements change. Always confirm with the Maryland State Board of Plumbing before you apply. This page is general information, not legal advice.
More: our plumbing license guide explains how licensing works nationally, and the plumbing license by state hub lists every state we have covered. Ready to run the business side? Start with how to start a plumbing business and plumbing business insurance.
