The Maryland plumbing code is the 2021 International Plumbing Code, adopted statewide and enforced by the Maryland Board of Plumbing under the Department of Labor. It governs who can perform plumbing and gas work, how that work must be installed and inspected, and what happens when someone works outside the rules. Local jurisdictions can layer their own requirements on top, and two of them run their own licensing programs entirely.1Maryland Department of Labor. Current Adopted Building-Related Codes in the State of Maryland
What Code Applies and Who Enforces It
The Board of Plumbing enforces the IPC for all buildings except modular and state-owned structures, which fall under the Division of Labor and Industry. Counties and municipalities can also adopt their own plumbing codes for buildings within their boundaries, so the IPC sets the floor and local amendments fill in above it.1Maryland Department of Labor. Current Adopted Building-Related Codes in the State of Maryland
The code covers installation, maintenance, and modification of water supply piping, drainage, venting, and fixtures. All components must be approved by recognized testing agencies. Pipe sizing and slope are specified. Water-saving fixtures such as low-flow toilets and faucets are mandatory. If plumbing work is being done in Maryland, the IPC is the reference; anything a local jurisdiction adds sits on top of it.
Who Can Legally Do the Work
The Board licenses anyone who provides or assists in providing plumbing and gas services in the state, in three tiers.2Maryland Department of Labor. Maryland Board of Plumbing – Division of Occupational and Professional Licensing
- An apprentice plumber or gas fitter is the entry point. You can apply at age 16 with no prior experience, and you work under the direct supervision of a licensed master plumber.
- A journey plumber or gas fitter must have held an apprentice license for at least four years, completed 7,500 hours of training under a master plumber, finished 32 hours of backflow prevention device training, and passed a written examination.
- A master plumber or gas fitter must have held a journey license for at least two years, completed 3,750 additional hours of training under a master plumber, and passed a comprehensive written examination.
The path from apprentice to master takes at least six years of supervised work and two separate licensing exams.3Maryland Department of Labor. License Requirements – Plumbing For a homeowner hiring out work, the practical takeaway is that only a licensed master plumber can independently contract and supervise; anyone else on the crew works under that master’s license.
Gas Fitting Certifications
Maryland issues separate licenses for natural gas fitters and propane gas fitters. A master natural gas fitter needs either a current county-level gas fitter license or at least four years of experience plus an approved training program. A propane gas fitter certification requires completing the National Propane Gas Association’s training program for distribution systems operations, or demonstrating equivalent qualifications.3Maryland Department of Labor. License Requirements – Plumbing
Where Your State License Doesn’t Work
A state plumbing license from the Board is not valid everywhere in Maryland. Baltimore County and the areas served by the Washington Suburban Sanitary Commission, which covers Prince George’s and Montgomery Counties, run their own licensing programs.2Maryland Department of Labor. Maryland Board of Plumbing – Division of Occupational and Professional Licensing A state-licensed plumber taking a job in one of those jurisdictions needs the local credential too. Confirm which license the job requires before bidding.
Backflow Prevention Requires a Separate Certification
Cross-connection and backflow prevention has its own regulatory framework under COMAR 09.20.04. Only licensed master or journey plumbers who have completed a Board-approved 32-hour cross-connection/backflow prevention certification program can install, test, or certify mechanical backflow prevention devices. Apprentice plumbers can assist but cannot perform these tasks independently.4Maryland Register. COMAR 09.20.04.02 – Approved Cross Connection/Backflow Prevention Certification
The certification is not permanent. Technicians must recertify every five years, and the training programs themselves must maintain ongoing recertification credentials to keep their Board approval.
Permits and Inspections
Plumbing work in Maryland requires a permit, and permits trigger mandatory inspections. Inspections generally happen in two phases: a rough-in inspection while walls and floors are still open (verifying pipe sizing, slope, venting, and materials before anything gets concealed), and a final inspection after fixtures are installed and systems are pressurized.
Permit fees vary by jurisdiction. The Maryland OneStop portal lists plumbing permit application costs roughly in the $25 to $100 range, but the actual fee depends on the scope of work and the county or municipality issuing the permit. Small projects are not automatically exempt. Replacing a water heater or moving a drain line can trigger the permit and inspection process, and work done without a permit tends to surface at resale.
Penalties for Working Outside the Rules
Penalties under the Business Occupations and Professions Article, Title 12, Subtitle 6 are tiered by severity.
- Employing unauthorized workers or related violations under §§12-602, 12-603, and 12-604 are misdemeanors carrying a fine of up to $50 for each day the violation continues.
- Practicing without a license or related violations under §§12-601, 12-605, and 12-606 are misdemeanors carrying a fine of up to $100 per day, imprisonment of up to six months, or both.
- Willful violations of licensing provisions under §12-501(a) are misdemeanors with a fine of up to $1,000, imprisonment of up to six months, or both.
On top of the criminal penalties, the Board can impose an administrative penalty of up to $5,000 per violation.5New York Codes, Rules and Regulations. Maryland Code Business Occupations and Professions 12-607 – Fines and Penalties The administrative fine stacks. A plumber who employs an unlicensed worker on a two-week project can face daily criminal fines plus the Board’s administrative penalty on the same conduct.
Renewal and Continuing Education
Licensed plumbers must complete approved continuing education as a condition of renewal, under requirements the Board sets through COMAR 09.20.01. The obligation keeps plumbers current on code changes, new technologies, and safety practices. If continuing education lapses, renewal stalls, and working on an expired license exposes you to the same penalties as working without one.
Approved CE providers and courses change over time. Before renewal, verify current approval directly with the Board rather than assuming a previous course still qualifies.
What Homeowners Get Back If a Contractor Fails
Homeowners who hire a licensed contractor for plumbing work that qualifies as a home improvement project have a financial backstop through the Maryland Home Improvement Commission’s Guaranty Fund. If a contractor takes payment and disappears, does defective work, or otherwise fails to perform, the homeowner can file a claim.
The maximum recovery is $30,000 per claimant, or the amount actually paid to the contractor, whichever is less. Payouts are capped at $250,000 per contractor across all claimants; if approved claims exceed that cap, the Commission prorates payments so each claimant receives the same percentage.6Maryland Department of Labor. Guaranty Fund FAQs – Home Improvement Commission The fund only covers licensed home improvement contractors. Hiring an unlicensed plumber eliminates this recourse.
Water Heater Rules That Fail Inspections
A few IPC provisions adopted in Maryland catch homeowners and newer plumbers off guard. Water heaters must have approved temperature and pressure relief valves installed in the tank shell, with the temperature relief valve positioned to sense water temperature in the top six inches of the tank. Relief valves cannot double as thermal expansion controls. Systems with both a separate storage tank and a storage water heater need their own relief valves on each, and no shutoff or check valve can sit between a relief valve and the equipment it protects.
Water heaters also require a level working space of at least 30 inches by 30 inches for maintenance access. A water heater installed correctly in a closet that does not allow servicing is still a code violation. These requirements come directly from the IPC provisions Maryland has adopted and apply regardless of the local jurisdiction.