Maryland State Board of Plumbing (Maryland Department of Labor, Division of Occupational and Professional Licensing) administers plumber licensing in Maryland. Every figure below is verified against the board’s own official pages and dated. Who must personally hold a credential — the contractor, the business, or the individual worker — is set out under Requirements.
What it’s called
Maryland’s plumbing licences are combined plumbing-and-gas licences: the Board’s titles are Apprentice, Journey and Master Plumber/Gas Fitter, and by statute a master plumber is licensed “to provide plumbing services and natural gas services” and “includes a master plumber gas fitter” (BOP 12-101(l)). The statute and the Board use both “journey” and “journeyman” (the Board’s fee page: “Journeyman Plumber/Gas Fitter”). Separate gas-only credentials exist for non-plumbers – apprentice, journeyman and master natural gas fitter licences and a propane gas fitter certificate. The issuing body is the State Board of Plumbing in the Maryland Department of Labor; its online applications still run on the Department’s older dllr.state.md.us address. Baltimore County and the Washington Suburban Sanitary Commission (WSSC) issue their own plumber licences, which the State Board’s licences do not replace there (BOP 12-103).
License types & fees
| Type | Experience | Exam | Fee |
|---|---|---|---|
| Apprentice Plumber/Gas Fitter license -- the entry credential | None to apply. License Requirements page: "Person must be at least 16 years of age." The Department's application: "The term "Apprentice" applies to a person who is learning the trade under the direction and control of a Licensed Master Plumber/Gas Fitter or a licensed Master Natural Gas Fitter." Training hours count toward the journey licence only under a master plumber: "If they practice under a licensed Master Plumber/Gas Fitter , the hours of training can be applied toward a Journey Plumber/Gas Fitter license"; under a master natural gas fitter "the hours of training can be only applied toward a Journey Natural Gas Fitter license." The licence is separate from state apprenticeship registration: "This registration is for purposes of the State Board of Plumbing only; it does not exempt you from the registration requirements of the Maryland Apprenticeship and Training Council of the Department of Labor when applicable." | None. | $18.50 original licence and $18.50 renewal (Board Forms and Fees page, "Updated July 1, 2025"; COMAR 09.20.05.03B lists "Apprentice Plumber/Gas Fitter — $18.50" as the application fee and the same amount for renewal). |
| Journey Plumber/Gas Fitter license | BOP 12-302(c)(1): the applicant "shall have held, for a period of at least 4 years, an apprentice plumber license or a license of equal stature, as determined by the Board, that is issued by another state" and during that period "shall have completed at least 7,500 hours of training in providing plumbing services under the direction and control of a licensed master plumber", and "shall have completed at least 32 hours of training in the testing of backflow prevention devices, in a manner approved by the Board." The Board "may allow the applicant to apply up to 1,500 hours of accredited, approved school study toward the experience requirement" (12-302(c)(2)). COMAR 09.20.02.03A(3): "Hours accrued may not be credited to an individual serving under an apprenticeship agreement registered with the Maryland Apprenticeship and Training Council unless the individual is also licensed with the Board as an apprentice plumber." PSI's bulletin adds that "Only work experience as a licensed Apprentice will count towards meeting the work experience requirement" and that "Hours certified by secretaries, bookkeepers, or other office personnel will not be accepted." OFFICIAL SOURCES POINT DIFFERENT WAYS ON UNLICENSED HOURS, both recorded: COMAR 09.20.02.02 requires the apprentice, before the journey examination, to "Be registered with the Board for the duration of the apprenticeship training" but also provides: "To avoid undue hardship, the Board may give credit for hours worked in the installation and repair of plumbing material and systems by an unregistered apprentice plumber." PSI's bulletin says only licensed-apprentice hours count, and BOP 12-302(c)(1)(i) counts the 7,500 hours completed "during that period" of holding the apprentice licence. Whether particular unregistered hours are credited is left to the Board. | Yes -- PSI's Journey Plumber/Gas Fitter exam: 100 questions, 70% to pass, 240 minutes, open book. | $43.50 original licence and $43.50 renewal (Board fee page; COMAR 09.20.05.03B "Journey Plumber/Gas Fitter — $43.50"), plus PSI's $65 exam fee (PSI bulletin). |
| Master Plumber/Gas Fitter license | BOP 12-302(d): "at least 3,750 hours of training in providing plumbing services as a journey plumber licensed in this State or another state and under the direction and control of a licensed master plumber"; "if an applicant resides in this State, shall have a journey plumber license for at least 2 years", or have been licensed in another state as a journey plumber after 7,500 supervised hours and "passing a written examination that is equivalent to the examination for a journey plumber license given in this State"; and the 32 hours of backflow-prevention testing training. License Requirements page: "Person must have held a journey license for at least two years; and Person must have completed 3,750 hours of training under the direction and control of a licensed master plumber; and Person must pass a comprehensive written examination." COMAR 09.20.02.04G: a nonresident or an applicant whose experience was not in Maryland "shall accrue a total of at least 11,250 working hours, that is, 6 years of practical experience", documented as 7,500 hours under a master plus 3,750 hours as a journey plumber, with certification that both the applicant's journey licence and the supervising master's licence were obtained by written competency examination. COMAR 09.20.02.04G(3) adds a route for a nonresident "from an area that does not require licensure of journeyperson plumbers" who "holds a master plumber's license": certification of at least 7,500 hours under a licensed master who was licensed by written examination, a master licence itself received by written competency examination, and at least 2 years (3,750 working hours) of installation and repair since receiving that master licence. A master plumber licence "includes a master plumber gas fitter" (BOP 12-101(l)(2)). | Yes -- PSI's Master Plumber/Gas Fitter exam: 100 questions, 70% to pass, 240 minutes, open book. | $87.50 original licence and $87.50 renewal (Board fee page; COMAR 09.20.05.03B "Master Plumber/Gas Fitter — $87.50"), plus PSI's $65 exam fee. Contracting requires liability insurance (see requirements). |
| Apprentice Natural Gas Fitter license (natural gas only, for non-plumbers) | License Requirements page: "Person must be at least 16 years of age." The application: "The hours of training will always be applied towards a Journey Natural Gas Fitter license." | None. | $18.50 original licence and $18.50 renewal (Board fee page; COMAR 09.20.05.03B "Apprentice Natural Gas Fitter — $18.50"). |
| Journeyman Natural Gas Fitter license | BOP 12-302(g)(1): "shall have acquired 3,750 working hours as an apprentice natural gas fitter over a period of at least 2 years" and "shall have demonstrated successful completion of a training course approved by the Board relating to natural gas services." License Requirements page also allows "a current journey gas fitter license from Baltimore County or WSSC". | Yes -- PSI's Journey Natural Gas Fitter exam: 40 questions, 70% to pass, 90 minutes. | Conflict between official sources: the Board fee page lists "Journeyman Natural Gas Fitter - $68.50" as the original licence fee; COMAR 09.20.05.03B lists an application fee of "Journey Natural Gas Fitter — $31.50" and an original licence fee of "Journeyman Natural Gas Fitter — $43.50". Renewal $31.50 on both. PSI exam fee $25. |
| Master Natural Gas Fitter license | Open route, BOP 12-302(h)(3): pass the Board's written examination with, at a minimum, "proof of a current master or master restricted heating license in good standing issued by the State Board of Heating, Ventilation, Air-Conditioning, and Refrigeration Contractors" and "2 years of work experience as a journeyman natural gas fitter" under a licensed master plumber, licensed master gas fitter, or qualifying HVACR master. The License Requirements page also lists "a current master gas fitter license from Baltimore County or WSSC" and "at least four years of experience, and completed an approved training program" -- in the statute that last route (12-302(h)(2)) required applying to the Board "before October 1, 2002". | Yes -- PSI's Master Natural Gas Fitter exam: 40 questions, 70% to pass, 90 minutes. | $150.50 original licence on the Board fee page (COMAR 09.20.05.03B: $63 application plus $87.50 original licence); renewal $43.50; PSI exam fee $65. |
| Propane Gas Fitter Certificate (propane only, for non-plumbers) | BOP 12-302(f): hold "a current certification of completion of the National Propane Gas Association Certified Training Program for Distribution Systems Operations"; or a county or municipal gas fitters licence "under a licensing program that is in existence prior to July 1, 1995 and that is acceptable to the Board"; or "otherwise demonstrate qualifications that are satisfactory to the Board" and at least equivalent to that program. | None stated for the certificate. | Conflict between official sources: Board fee page "$25.00 Initial application fee" and "$ 31.50 License fee"; COMAR 09.20.05.03B "Propane Gas Fitter Certificate — $31.50" application and "Propane Gas Fitter — $43.50" original certificate. Renewal $43.50 (COMAR). |
| Limited Master Plumber / Limited Journey Plumber license (closed to new applicants) | BOP 12-310(d): "After June 30, 1991, the Board may not issue a limited license to provide plumbing services to any individual." Existing holders may keep renewing (12-310(e)). A limited licence covers "only in a specified geographical area of the State" (12-310(b)). | Renewal only; no new issuance. | Renewal $87.50 (limited master) and $43.50 (limited journey) per COMAR 09.20.05.03B. |
| Plumbing Inspector certification / inspector identification card (government inspectors) | License Requirements page: "Person must be a licensed master or journey plumber; and Person must have at least four years’ experience as an inspector or craftsman in a building and construction trade; and Person must pass a written examination prepared and administered by the Board; and Person must place their master’s license on inactive status prior to obtaining plumbing inspector certification." That is how the License Requirements page states it. OTHER OFFICIAL SOURCES DESCRIBE THE ROUTES DIFFERENTLY, all recorded: the Board's online inspector application lists three cards -- "Master Inspector - You must be a licensed Master Plumber to apply for a Plumbing Inspector's Card and, upon appointment, you must surrender your current license to the Board."; "Journeyman Inspector - You must be a licensed Journey Plumber to apply for a Plumbing Inspector's Card and, upon appointment, you must surrender your current license to the Board."; and "Non-Master Inspector - You must have at least four years experience as an inspector or craftsman in a building and construction trade and pass a written examination to qualify for a Plumbing Inspector's Card." Board FAQ 8 says the same of the non-master card: "An individual may obtain an inspector identification card as non-master plumber if the individual has at least four years’ of experience as an inspector or craftsman in a building and construction trade and pass a written examination." So under the application and FAQ 8 the non-master card requires no plumbing licence, while the License Requirements page lists a master or journey licence AND four years' experience AND the examination. Every card also requires employment by a local government agency, or by a company with a contract to perform plumbing inspections for one, plus an original employment-verification letter on the agency's letterhead signed by the chief of inspections or someone of higher rank, submitted with the application and with each renewal (inspector application; FAQ 9). The statute sets its own rule for local hiring: "a county or local government may employ an individual as a plumbing inspector only if the individual holds a master plumber license issued by the Board, the Baltimore County Plumbing Board, or the Washington Suburban Sanitary Commission" (BOP 12-503(b)(1)), except a county or local government that uses combination building code inspectors who, as part of their training, passed a master plumber examination given by one of those three bodies or the Board's plumbing inspector test (BOP 12-503(b)(2)). COMAR 09.20.02.10A makes the Board's list a fallback: inspectors hired after October 1, 1988 meet "minimum standards that are established by the county or local government in consultation with the State Board", or, "if there is no standard established by the county or local government", the Board's minimum standards ("The plumbing inspector shall be a licensed master or journey plumber", at least 4 years' experience as an inspector or craftsman, and a written examination). | The License Requirements page and COMAR 09.20.02.10A list a written examination prepared and administered by the Board (COMAR 09.20.02.10A also allows a county or local government examination approved by the Board). The Board's inspector application names a written examination only for the Non-Master card. | $56 original and $56 renewal (COMAR 09.20.05.03B: Master, Journeyman and Plumbing Inspector). |
Who does NOT need this license — exemptions
BOP 12-301 exemptions, quoted in full. (b)(1) “Subject to paragraph (2) of this subsection, this section does not apply to an individual who personally provides plumbing services in the residence of the individual.” (b)(2) “An individual may not provide plumbing services that make a final connection between the residence of the individual and a public or private disposal system or water supply system.” (c) “This section does not apply to an employee of a gas company regulated by the Public Service Commission while making a connection to a gas appliance for domestic purposes or while installing, repairing, maintaining, replacing, or performing any other work on a natural gas, propane gas, or other gas distribution system, including customer-owned gas piping systems.” (d) “This section does not apply to an individual performing work that is only incidental to the licensee providing or assisting in providing plumbing services.” (e) “This section does not apply to an individual who, without compensation, provides plumbing services that the Board defines by regulation to be only incidental plumbing services.” (f) “This section does not apply to an employee of a building owner, manager, or maintenance company who provides plumbing services that the Board defines by regulation to be only minor plumbing repair services.” (g) “This section does not apply to an individual who is licensed as an appliance installer in Allegany County, Frederick County, Garrett County, or Washington County while acting within the scope of the license.” (h) “This section does not apply to an individual who is licensed in Washington County to work as or for a septic system installer or an on-site utility contractor installing water or sewer service in the county at least 5 feet from a building being served.” (i) “Subsection (a)(3) and (4) of this section does not apply to an individual licensed by the State Board of Heating, Ventilation, Air-Conditioning, and Refrigeration Contractors while servicing an existing propane gas or existing natural gas appliance if the individual has completed a manufacturer’s training course certifying competence to work on that particular type of appliance.” The regulatory definitions of “incidental plumbing services” and “minor plumbing repair services” referred to in (e) and (f) were not located in COMAR 09.20 and are not stated here. WHOLE-JURISDICTION CARVE-OUT, BOP 12-103: the title “does not apply to Baltimore County” and does not apply “to areas of Montgomery and Prince George’s counties that are under the jurisdiction of the Washington Suburban Sanitary Commission”, except as provided in 12-305, 12-307 and 12-503(b); those areas license plumbers themselves. OUTSIDE THE DEFINITION OF PLUMBING SERVICES, BOP 12-101(n)(3): except for “the first connection to a potable water supply that is downstream of a backflow preventer and the final connection that discharges indirectly into a public or private disposal system, sanitary drainage facility, or storm drainage facility”, providing plumbing services “does not include using piping, equipment, or material only for: (i) environmental control; (ii) the incorporation of a liquid or gas into a product or into a process, including product development, in the manufacture or storage of a product; (iii) the installation, alteration, repair, or removal of an automatic sprinkler system, related apparatus, or standpipe that is used only for fire protection; or (iv) an overhead or underground fire line beginning from where water is used only for fire protection.” INSURANCE ONLY: “An apprentice plumber, journey plumber, or holder of a limited journey plumber license need not obtain separate insurance while providing or assisting in providing plumbing services within the scope of the license” (BOP 12-501(c)).
Fees
Board Forms and Fees page (“Updated July 1, 2025”), original licence: Master Plumber/Gas Fitter $87.50; Journeyman Plumber/Gas Fitter $43.50; Apprentice Plumber/Gas Fitter $18.50; Apprentice Natural Gas Fitter $18.50; Journeyman Natural Gas Fitter $68.50; Master Natural Gas Fitter $150.50; Propane Gas Fitter Certificate “$25.00 Initial application fee” plus “$ 31.50 License fee”. Renewal: Master Plumber/Gas Fitter $87.50; Journeyman Plumber/Gas Fitter $43.50; Apprentice (either) $18.50; Master Natural Gas Fitter $43.50; Journeyman Natural Gas Fitter $31.50. COMAR 09.20.05.03B (fees set “as of January 1, 2025”; regulation amended effective March 4, 2024) agrees on the plumber and apprentice amounts but differs for two gas credentials: Journey Natural Gas Fitter application $31.50 plus original licence $43.50 (page: $68.50), and Propane Gas Fitter Certificate application $31.50 plus original certificate $43.50 (page: $25.00 plus $31.50). Both sources are stated; neither is resolved here. Other COMAR fees: inspector original and renewal $56; licence reactivation Master Plumber/Gas Fitter $63, Journey Plumber/Gas Fitter $25; “Letter of Good Standing — $50”. Exam fees are paid to PSI (COMAR 09.20.05.03C): “Master Plumber/ Gas Fitter $65”, “Journey Plumber/Gas Fitter $65”, “Master Natural Gas Fitter $65”, “Journey Natural Gas Fitter $25” (PSI bulletin, Updated 9/1/2024); “Examination registration fees are not refundable and are not transferable.”
Exam
PSI administers all Board exams: “PSI Examination Services provides all testing for the MD State Board of Plumbing. PSI has testing centers located in Baltimore, College Park, Hagerstown, Lanham, and Salisbury.” Apply to PSI first and upload proof: “Proof of hours worked”, “A copy of your backflow certification” and a copy of the driver’s license (Board exam page); PSI’s bulletin: “Effective 3/31/2025 PSI will no longer be processing applications via mail, fax or email.” Formats (PSI Candidate Information Bulletin, “Updated 9/1/2024”): Master Plumber/Gas Fitter and Journey Plumber/Gas Fitter – 100 questions, 70% minimum passing score, 240 minutes; Master Natural Gas Fitter and Journey Natural Gas Fitter – 40 questions, 70%, 90 minutes. The plumber exams weight “GAS APPLIANCES AND PIPING” at 40 items. “This examination is OPEN BOOK.” References for the plumber exams: “International Plumbing Code, 2018”, “International Fuel Gas Code, 2018”, “Mathematics for Plumbers and Pipefitters, Lee Smith, 8th Edition, 2013”, “Any standard backflow text” and 29 CFR Part 1926. Passing score in rule: “an applicant for any license or certificate issued by the Board shall attain a passing score of 70” (COMAR 09.20.02.11). Retakes: “A period of 1 month shall elapse before a failed applicant may retake an examination” (COMAR 09.20.02.06A); PSI: “YOU MAY NOT TAKE THE EXAMINATION MORE OFTEN THAN EVERY 30 DAYS.” After passing: “you have one year from the date you took the exam to apply for a license for a passing score to be valid” (FAQ 24).
Renewal & continuing education
Two-year term. Conflict on WHEN licences expire: BOP 12-308(a) – “unless a license is renewed for a 2–year term as provided in this section, the license expires on the first May 1 that comes” after the effective date and “in an odd–numbered year” (12-308(e): “The Secretary may determine that licenses and certificates issued under this subtitle shall expire on a staggered basis”); the Board’s renewal page – “All licenses and certificates issued by the State Board of Plumbing expire TWO YEARS FROM DATE OF ISSUE.” The Board sends a renewal notice “approximately 60 days prior to the expiration date”; the statutory floor is “At least 1 month before a license expires” (BOP 12-308(b)(1)). Apprentices: BOP 12-308.1(a) – for an apprentice plumber or apprentice natural gas fitter “issued an initial license on or after October 1, 2012, the Board may not renew the license for more than three consecutive terms if the licensee has not taken or registered to take a journey plumber examination or journeyman gas fitters examination”, with an extra 2-year term for each failed exam (12-308.1(b)); the Board’s fee page instead says “By law an Apprentice Natural Gas Fitter or Apprentice Plumber/Gas Fitter license may only be renewed for two (2) consecutive cycles before you must take the journey exam.” Lapsed licences: BOP 12-309 – reinstatement “within 4 years after the license expires” on meeting renewal requirements; after 4 years the applicant must also pass the examination; the Board: “If an individual licensee allows his or her license/certificate to lapse and fails to renew it for more than four years, the individual must file a new application and pass the appropriate examination.” COMAR 09.20.02.07C says “Any applicant for renewal who has for 5 consecutive years failed to renew a license is subject to examination” – a conflict with the statute’s 4 years. Masters who contract must show the 12-501 insurance to renew (BOP 12-501(e)). None for licensed plumbers and gas fitters. Board FAQ 16: “There are no continuing education requirements to maintain a Maryland license. However, eight hours of continuing education are required each calendar year to maintain a plumbing inspector identification card.” Education page: “The Maryland State Board of Plumbing requires eight hours of continuing education credits each calendar year for plumbing inspectors only.” COMAR 09.20.02.10B(2): inspectors “obtain a cumulative 8 hours of qualifying continuing education each calendar year.”
How to apply
Applications are handled by Maryland State Board of Plumbing (Maryland Department of Labor, Division of Occupational and Professional Licensing). Start at the official application page .