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How to get a Journey Plumber/Gas Fitter license in Maryland

Maryland licenses plumbers statewide through the Maryland Board of Plumbing.1 For the Journey Plumber/Gas Fitter license you need at least 32 clock hours2 of education, at least 7,500 hours of on-the-job training2, a passing score on the Maryland Journey Plumber/Gas Fitter examination (PSI)3 and a criminal background check4. The board lists $43.50 for the initial license5. You renew every 2 years6.

Last checked · 27 official sources

Who issues it

Maryland Board of Plumbing

Training and experience

Training: at least 32 clock hours2
Experience: at least 7,500 hours of on-the-job training2

Exam

Maryland Journey Plumber/Gas Fitter examination (PSI)3

Fees the board lists

Exam fee: $653
Initial license fee: $43.505

Renewal

Every 2 years6

From another state

Reciprocity agreements7 Details

On this page
  1. Maryland plumber licenses
  2. Applies to every license level
  3. Who needs a Journey Plumber/Gas Fitter license
  4. Requirements for a Journey Plumber/Gas Fitter license
  5. How much a Journey Plumber/Gas Fitter license costs
  6. How to apply
  7. Renewal and continuing education
  8. Moving to Maryland with a license from another state
  9. Apprentice Natural Gas Fitter
  10. Apprentice Plumber/Gas Fitter
  11. Journey Natural Gas Fitter
  12. Master Natural Gas Fitter
  13. Master Plumber/Gas Fitter
  14. City and county rules
  15. Check a license or report a problem
  16. Laws and rules
  17. Rule changes since January 2024
  18. Common questions
  19. Plumber licenses in other states

Maryland plumber licenses

Maryland issues 6 plumber credentials. Each has its own section below; the table shows what each one covers and its headline requirements.

LicenseWhat it coversTraining or experienceExamApplication or license fee
Apprentice Natural Gas FitterProvides natural gas service only under the direction and control of a licensed master natural gas fitter, while training to become a journeyman.8–No9$18.505
Apprentice Plumber/Gas FitterAssists in plumbing services only under the direction and control of a master plumber; a master or journey licensee must be present on the job site and apprentices may not work alone.8–No9$18.505
Journey Natural Gas FitterProvides natural gas services only under the direction and control of a licensed master natural gas fitter.8Experience 3,750 hours2Yes10–
Journey Plumber/Gas FitterProvides plumbing services only under the direction and control of a master plumber (or limited master); cannot contract.8Training 32 clock hours2
Experience 7,500 hours2		Yes10$43.505
Master Natural Gas FitterProvides natural gas services (piping, gas-fired equipment and appliances downstream of the utility point of delivery); does not cover plumbing.8Experience 2 years9Yes10$635
Master Plumber/Gas FitterProvides plumbing services and natural gas services; only insured master plumbers may contract for plumbing or gas work. Must display the license at the place of business and the license number on each work vehicle.11Training 32 clock hours2
Experience 3,750 hours2		Yes10$87.505

Applies to every license level

These rules are the same for several of the Maryland plumber licenses on this page, so they are shown once here, with the licenses they apply to. Each license's own section lists only what differs.

1. Every license level (all 6)

Requirements

Background check
Background check required4
A conviction does not automatically disqualify; the Board weighs the nature of the crime, time since conviction and later conduct, case by case, and a denied applicant may request a hearing.4
You can ask the board to review your record before you apply12

Fees

FeeAmountPaid toNotes
Predetermination review$10012Maryland Board of PlumbingOptional criminal history predetermination review before applying (waivable at or below 300% of the federal poverty line)

How to apply

Apply online
dllr.state.md.us13

Renewal

How often
Every 2 years6
When it expires
Licenses expire 2 years from the date of issue (staggered); the Board e-mails a renewal notice about 60 days before expiry. (The statute's default is May 1 of odd-numbered years, but the Secretary may stagger expirations.)6
Renew online
dllr.state.md.us6

From another state

Military service members, veterans and spouses: Expedited licensing for qualified service members, veterans and military spouses; the Division issues the license within 60 days of a complete application.14

2. Every license level except Apprentice Natural Gas Fitter and Apprentice Plumber/Gas Fitter

Requirements

Also required
Provide a copy of your driver's license and the actual street address of your residence or principal business office (no P.O. box).15

Fees

FeeAmountPaid toNotes
License verification to another state$505Maryland Board of PlumbingNot refundable. Effective January 1, 2025

3. Journey Plumber/Gas Fitter, Master Natural Gas Fitter and Master Plumber/Gas Fitter

Fees

FeeAmountPaid toNotes
Exam fee$653PSI Services LLCNot refundable. Effective September 1, 2024

4. Journey Plumber/Gas Fitter and Master Natural Gas Fitter

Renewal

Renewal fee
$43.505

5. Journey Plumber/Gas Fitter and Master Plumber/Gas Fitter

Requirements

Education or training
At least 32 clock hours2
32-hour cross connection/backflow prevention device testing course from a Board-approved provider (certificate must be current at exam application)3
Who may teach it: Board-approved cross connection/backflow prevention certification program (COMAR 09.20.04); approved providers listed on the Board site. No license needed to enroll.16

How to apply

Processing time
License mailed within two weeks of applying.4

6. Apprentice Natural Gas Fitter and Apprentice Plumber/Gas Fitter

Requirements

Minimum age
16 years old9
Exam
Not required9

Fees

FeeAmountPaid toNotes
Application fee$18.505Maryland Board of PlumbingNot refundable. Effective January 1, 2025

Renewal

Renewal fee
$18.505

7. Master Natural Gas Fitter and Master Plumber/Gas Fitter

Fees

FeeAmountPaid toNotes
Initial license fee$87.505Maryland Board of PlumbingNot refundable. Effective January 1, 2025

Who needs a Journey Plumber/Gas Fitter license

Provides plumbing services only under the direction and control of a master plumber (or limited master); cannot contract.8

Work that does not need this license:

  • Homeowners may do plumbing in their own residence, but may not make the final connection to a public or private sewer/disposal or water supply system.1
  • Gas company employees (PSC-regulated) connecting domestic gas appliances or working on gas distribution systems are exempt.1
  • Building owner/manager/maintenance-company employees doing minor plumbing repairs (as defined by Board regulation) and unpaid incidental plumbing are exempt.1
  • Licensed HVACR contractors servicing an existing propane or natural gas appliance after a manufacturer's training course do not need a plumbing or gas license for that work.1

Other rules on who may do this work:

  • Unlicensed work: fine up to $100 or up to 6 months in jail (or both) for each day, or up to $5,000 per violation.17

Requirements for a Journey Plumber/Gas Fitter license

More rules for this license are shared with other levels: group 1, group 2, group 3, group 4 and group 5 under Applies to every license level.

Experience
At least 7,500 hours of on-the-job training2
Training as a licensed apprentice plumber under the control and direction of a licensed master plumber9
Supervision: Licensed master plumber; hours certified by office staff are not accepted, and out-of-state masters need a verification letter that they were licensed by written exam.3
License you must hold first: Apprentice plumber license (or another state's license of equal stature) held at least 4 years; only hours as a licensed apprentice count, including under a registered MATC apprenticeship.18
Substitute: Up to 1,500 hours of accredited, approved school study (MSDE-accredited vocational/technical program or registered apprenticeship classroom work) may count toward the 7,500 hours.18
Exam
Maryland Journey Plumber/Gas Fitter examination (PSI)3
Given by: PSI Services LLC10
Passing score: 70% (100 questions, 240 minutes)19
When you can take it: Must be a licensed apprentice with 7,500 certified hours (up to 1,500 school hours may count) and a current 32-hour backflow course; apply to PSI online with proof.3
Content outline: 100 items across plumbing fundamentals and safety, materials, traps, fixtures, water supply, backflow, DWV, gas; open book3
Retakes: Re-register with PSI and pay the fee again; no more often than every 30 days (COMAR: 1 month must elapse).3
Time limit: Apply for the license within 1 year of the exam date or the passing score lapses; PSI registration fees are valid for one year.4
Exam waived: Exam waived only for reciprocal licenses (Baltimore County / WSSC licenses obtained by exam; Delaware master plumber/gasfitter).7
Insurance
Journey plumbers need no separate insurance while working within the scope of the license.20

How much a Journey Plumber/Gas Fitter license costs

FeeAmountPaid toNotes
Initial license fee$43.505Maryland Board of PlumbingNot refundable. Effective January 1, 2025

How to apply

  1. Hold an apprentice license for at least 4 years while logging 7,500 hours under a licensed master (up to 1,500 approved school hours can count).9
  2. Complete a Board-approved 32-hour backflow prevention device testing course.9
  3. Apply to PSI online with proof of hours, backflow certificate and driver's license; once approved, pay the $65 exam fee and schedule.10 test-takers.psiexams.com3
  4. Pass the 100-question open-book journey exam (70%) and apply for the license within one year.4
  5. Apply online for the original license and pay the $43.50 license fee.4 dllr.state.md.us13

Renewal and continuing education

Late renewal
Reinstatement fee: $255 (reactivating an inactive license)

Renewal planner

Enter the expiration date printed on your Maryland Journey Plumber/Gas Fitter license. The count is worked out on your device from today's date; nothing is sent anywhere.

Moving to Maryland with a license from another state

These are the routes the Maryland Board of Plumbing publishes for the Journey Plumber/Gas Fitter license. The other plumber licenses have their own routes in their sections below.

Route
Reciprocity agreements
What the board says
Reciprocal journey license for Baltimore County or WSSC journey licensees holding both plumbing and gas portions obtained by exam. The reciprocity page also lists DC; the FAQ does not. Delaware reciprocity is for master licenses only.7
Conditions
Supporting documents: verification letter, backflow certification, copy of current license and photo ID.7
Fee
$43.5021
Route
No reciprocity
What the board says
Other out-of-state applicants take the Maryland journey exam after certifying 7,500 hours (4 years) under a master who was licensed by written exam.18

Apprentice Natural Gas Fitter

Provides natural gas service only under the direction and control of a licensed master natural gas fitter, while training to become a journeyman.8

How to apply

  1. At 16 or older, apply online through "Original Apprentice Licenses" and pay $18.50.4 dllr.state.md.us13

From another state

Route
No reciprocity
What the board says
No reciprocity for apprentices.7

More rules for this license are shared with other levels: group 1 and group 6 under Applies to every license level.

Apprentice Plumber/Gas Fitter

Assists in plumbing services only under the direction and control of a master plumber; a master or journey licensee must be present on the job site and apprentices may not work alone.8

Requirements

Insurance
Apprentices need no separate insurance within the scope of the license.20
Also required
Hours count toward the journey license only while you are licensed as an apprentice; register before (or as soon as) you start working.3

How to apply

  1. At 16 or older, apply online through "Original Apprentice Licenses" on the Board Apply page and pay the $18.50 fee.4 dllr.state.md.us13
  2. Work only under a master (with a master or journey licensee on site) and log your hours toward the 7,500 needed for the journey exam.17
  3. Renew every 2 years ($18.50) and register for the journey exam before the renewal limit is reached.21

From another state

Route
No reciprocity
What the board says
No reciprocity for apprentices; apply as a new apprentice (age 16+).7

More rules for this license are shared with other levels: group 1 and group 6 under Applies to every license level.

Journey Natural Gas Fitter

Provides natural gas services only under the direction and control of a licensed master natural gas fitter.8

Requirements

Education or training
Board-approved training course relating to natural gas services2
Who may teach it: Course providers for natural gas fitters are listed in the PSI bulletin.3
Experience
At least 3,750 hours of on-the-job training2
Working hours as an apprentice natural gas fitter under a licensed master gas fitter or master plumber, over at least 2 years9
Supervision: Licensed master gas fitter or master plumber9
Substitute: A current Baltimore County or WSSC journey gas fitter license qualifies instead.9
Exam
Maryland Journey Natural Gas Fitter examination (PSI)3
Given by: PSI Services LLC10
Passing score: 70% (40 questions, 90 minutes)19
When you can take it: 3,750 natural gas fitter hours as an apprentice over at least 2 years and an approved course of study.3
40 questions, 90 minutes, open book3
Retakes: Re-register with PSI and pay the fee again; no more often than every 30 days (COMAR: 1 month must elapse).3
Time limit: Apply for the license within 1 year of the exam date or the passing score lapses; PSI registration fees are valid for one year.4
Exam waived: Exam waived only for reciprocal licenses (Baltimore County / WSSC licenses obtained by exam; Delaware master plumber/gasfitter).7

Fees

FeeAmountPaid toNotes
Exam fee$253PSI Services LLCNot refundable. Effective September 1, 2024

How to apply

  1. Log 3,750 hours over at least 2 years as a licensed apprentice natural gas fitter and complete an approved natural gas course.4
  2. Apply to PSI online, pay the $25 exam fee to PSI and pass the 40-question exam (70%).3 test-takers.psiexams.com3
  3. Apply online for the license and pay the Board fee.4 dllr.state.md.us13

Renewal

Renewal fee
$31.505

From another state

Route
Reciprocity agreements
What the board says
Holders of a current journey gas fitter license from Baltimore County or WSSC may obtain the like State license; no state-to-state reciprocity published.7
States on Maryland's list
The pages cited here give no list of partner states for this route; the board's words above say who qualifies. Ask the board which states it has agreements with.

More rules for this license are shared with other levels: group 1 and group 2 under Applies to every license level.

Master Natural Gas Fitter

Provides natural gas services (piping, gas-fired equipment and appliances downstream of the utility point of delivery); does not cover plumbing.8

Requirements

Education or training
Approved natural gas training program (for the 4-years-experience route)9
Who may teach it: Course providers for natural gas fitters are listed in the PSI bulletin (e.g. Maryland Association of Plumbing-Heating-Cooling Contractors).3
Experience
At least 2 years9
Routes: (1) current Baltimore County or WSSC master gas fitter license; (2) 4 years of experience plus an approved training program; or (3) Maryland HVACR master or master restricted license plus 2 years as a journey gas fitter under an approved master, and pass the exam.9
Supervision: Licensed master plumber, licensed master gas fitter, or approved HVACR master/master restricted heating licensee2
License you must hold first: Current Maryland HVACR master or master restricted heating license (exam route)3
Exam
Maryland Master Natural Gas Fitter examination (PSI)3
Given by: PSI Services LLC10
Passing score: 70% (40 questions, 90 minutes)19
When you can take it: Evidence of a current Maryland HVACR master or master restricted heating license plus 2 years as a licensed journeyman natural gas fitter; apply to PSI online.3
Content outline: general piping (15), pipe sizing/math (10), chimney and flues (5), combustion (5), appliances (5); open book3
Retakes: Re-register with PSI and pay the fee again; no more often than every 30 days (COMAR: 1 month must elapse).3
Time limit: Apply for the license within 1 year of the exam date or the passing score lapses; PSI registration fees are valid for one year.4
Exam waived: Exam waived only for reciprocal licenses (Baltimore County / WSSC licenses obtained by exam; Delaware master plumber/gasfitter).7

Fees

FeeAmountPaid toNotes
Application fee$635Maryland Board of PlumbingNot refundable. Effective January 1, 2025
Original License Fee$150.5021Maryland Board of PlumbingTotal original fee shown on the Board Forms and Fees page; not an additional charge

Some lines are combined figures, or parts of one; do not add the lines up.

How to apply

  1. Qualify by one of the routes (HVACR master + 2 years as journey gas fitter for the exam route).4
  2. Apply to PSI online, then pay the $65 exam fee to PSI and pass the 40-question exam (70%).3 test-takers.psiexams.com3
  3. Apply online for the license through "Apply for Original License" and pay the Board fees.4 dllr.state.md.us13

From another state

Route
Reciprocity agreements
What the board says
Holders of a current master gas fitter license from Baltimore County or WSSC may obtain the like State license. No state-to-state natural gas fitter reciprocity is published.7
States on Maryland's list
The pages cited here give no list of partner states for this route; the board's words above say who qualifies. Ask the board which states it has agreements with.
Conditions
Documents: verification letter from Baltimore County or WSSC, copy of license, photo ID, certificate of insurance (masters), and copy of current HVACR master license where applicable.4

More rules for this license are shared with other levels: group 1, group 2, group 3, group 4 and group 7 under Applies to every license level.

Master Plumber/Gas Fitter

Provides plumbing services and natural gas services; only insured master plumbers may contract for plumbing or gas work. Must display the license at the place of business and the license number on each work vehicle.11

Requirements

Experience
At least 3,750 hours of on-the-job training2
Training as a licensed journey plumber under the direction and control of a licensed master plumber9
Supervision: Licensed master plumber (Maryland Board, Baltimore County, WSSC, or another state's master license obtained by an equivalent exam)2
License you must hold first: Maryland residents: journey plumber license held at least 2 years; others: journey license from another state obtained after 7,500 hours and an equivalent written exam.2
Substitute: Out-of-state applicants (or Maryland work not done in Maryland) need 11,250 total hours (6 years): 7,500 as an apprentice under a master and 3,750 as a journey plumber, with letters verifying the licenses were obtained by written exam.22
Substitute: Applicants from areas that do not license journey plumbers but who hold a master license: 7,500 hours under an exam-licensed master plus 3,750 hours (2 years) as a master since licensing.22
Exam
Maryland Master Plumber/Gas Fitter examination (PSI)3
Given by: PSI Services LLC10
Passing score: 70% (100 questions, 240 minutes)19
When you can take it: Apply to PSI online with proof of hours, backflow certificate and ID; PSI approves eligibility (allow up to a week) before you pay and schedule.10
Content outline: 100 items incl. gas appliances and piping (40), drain/waste/vent (13), backflow prevention (10), water supply (8), plumbing mathematics (7) and other topics; open book (reference books, no study guides)3
Retakes: Re-register with PSI and pay the fee again; no more often than every 30 days (COMAR: 1 month must elapse).3
Time limit: Apply for the license within 1 year of the exam date or the passing score lapses; PSI registration fees are valid for one year.4
Exam waived: Exam waived only for reciprocal licenses (Baltimore County / WSSC licenses obtained by exam; Delaware master plumber/gasfitter).7
Insurance
To contract, a master must carry liability insurance including completed operations: at least $300,000 bodily injury and $100,000 property damage per occurrence (umbrella policies not accepted), with the Maryland State Board of Plumbing as certificate holder.23
Business requirements
A person (including a business) may engage in the business of providing plumbing services only under the conditions of BOP 12-401 (business run through a licensed master plumber).24
Also required
License and license number must be displayed at the principal place of business and on each vehicle used for plumbing services.17

How to apply

  1. Complete 3,750 hours as a licensed journey plumber under a licensed master (Maryland residents: hold the journey license 2+ years) and keep a current 32-hour backflow certificate.9
  2. Create a PSI account, apply online and upload proof of hours, backflow certificate and driver's license; after PSI approval, pay the $65 exam fee to PSI and schedule.10 test-takers.psiexams.com3
  3. Pass the 100-question open-book master exam (70%). You then have one year from the exam date to apply for the license.4
  4. Apply online for the original license, pay the $87.50 license fee, and (if you will contract) file a certificate of insurance naming the Maryland State Board of Plumbing as certificate holder.4 dllr.state.md.us13
  5. The license arrives by mail within about two weeks of applying.4

Renewal

Renewal fee
$87.505
Late renewal
Reinstatement fee: $635 (reactivating an inactive license)
If it expires
Masters who contract must keep liability insurance on file; proof is submitted with each renewal when contracting.25

From another state

Route
Reciprocity agreements
What the board says
Reciprocal master license for Delaware master plumber/gasfitters, and for Baltimore County or WSSC masters who hold both plumbing and gas portions obtained by exam. The reciprocity page also lists DC, but the licensing FAQ names only Delaware, WSSC and Baltimore County.7
States on Maryland's list
Delaware7
This is the list of states whose licenses Maryland accepts for this route. It does not say those states accept a Maryland license.
Condition for Delaware
Master Plumber/Gasfitter license only7
Conditions
Supporting documents: verification letter from the other jurisdiction, backflow certification, copy of current license, photo ID, and certificate of insurance (masters).7
Fee
$87.5021
Route
No reciprocity
What the board says
Other out-of-state plumbers must qualify for and pass the Maryland master exam, documenting 11,250 hours (7,500 apprentice + 3,750 journey) under exam-licensed masters.22

More rules for this license are shared with other levels: group 1, group 2, group 3, group 5 and group 7 under Applies to every license level.

City and county rules

Apprentice Natural Gas FitterState license everywhere; WSSC Water (Montgomery and Prince George's Counties) and Baltimore County run their own plumber/gasfitter licenses, and the State Board reciprocates with both.4

City or countyWhat it requiresLink
WSSC Water (Washington Suburban Sanitary District: Montgomery and Prince George's Counties) CountyWSSC Water issues Apprentice, Journeyman and Master Plumber / Gasfitter licenses (PSI-administered exams). Journeyman plumber: 7,500 hours under a WSSC-licensed master plus backflow certification; master: 3,750 hours as a journeyman. Fees: examined master $175 for 4 years, journeyman $60 per type for 2 years, apprentice $20 lifetime. WSSC reciprocates with Baltimore County, the State of Maryland and Virginia.26Official page26
Baltimore CountyThe Baltimore County Plumbing Board issues its own master and journey plumber licenses; the State reciprocates with it (both plumbing and gas portions, obtained by exam).7–

Check a license or report a problem

Before you hire a plumber in Maryland, you can confirm the license is current on the board's own search. Every board we cover in Maryland is on the Maryland license lookup page.

Look up a license
dllr.state.md.us4
File a complaint
labor.maryland.gov27

Laws and rules

The requirements above come from these laws and board rules.

Rule changes since January 2024

  • March 31, 2025: PSI stopped accepting exam applications by mail, fax or e-mail; applications must be filed online.3
  • January 1, 2025: New Board of Plumbing fee schedule took effect January 1, 2025 (e.g. master plumber/gas fitter license and renewal $87.50, up from $78 in 2024).5

Common questions

How long does it take to get a Journey Plumber/Gas Fitter license in Maryland?

The rules set at least 32 clock hours2 and at least 7,500 hours of on-the-job training2 before you can be licensed. On processing, the board says: License mailed within two weeks of applying.4

Can I transfer my plumber license to Maryland?

The Maryland Board of Plumbing publishes this route for the Journey Plumber/Gas Fitter license: reciprocity agreements7. Conditions and forms.

How often do you renew a Journey Plumber/Gas Fitter license in Maryland?

Every 2 years6. The renewal fee is $43.505.

Plumber licenses in other states

Sources

Every number and rule above links to one of these official pages. Select a footnote number to read the board's own words.

  1. Md. Code, Bus. Occ. & Prof. § 12-301Maryland General AssemblyChecked November 7, 2026
  2. Md. Code, Bus. Occ. & Prof. § 12-302Maryland General AssemblyChecked November 7, 2026
  3. PSI Qualification Information Bulletin (Master/Journey Plumber/Gas Fitter, Natural Gas Fitter)Maryland Department of Labor, State Board of PlumbingDated September 1, 2024Checked November 7, 2026
  4. Plumbing board page pllicfaqsMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  5. COMAR 09.20.05.03Maryland Division of State Documents (COMAR)Checked November 7, 2026
  6. Plumbing board page plrenewMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  7. Plumbing board page plrecipMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  8. Md. Code, Bus. Occ. & Prof. § 12-307Maryland General AssemblyChecked November 7, 2026
  9. Plumbing board page plreqMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  10. Plumbing board page plexamMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  11. Md. Code, Bus. Occ. & Prof. § 12-101Maryland General AssemblyChecked November 7, 2026
  12. Criminal history predetermination reviewMaryland Department of Labor, Division of Occupational and Professional LicensingChecked November 7, 2026
  13. Plumbing board page plapplyMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  14. Military veterans and families expedited licensingMaryland Department of Labor, Division of Occupational and Professional LicensingChecked November 7, 2026
  15. COMAR 09.20.03.02Maryland Division of State Documents (COMAR)Checked November 7, 2026
  16. Plumbing board page plbackflowMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  17. Plumbing board page plnolicMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  18. COMAR 09.20.02.03Maryland Division of State Documents (COMAR)Checked November 7, 2026
  19. COMAR 09.20.02.11Maryland Division of State Documents (COMAR)Checked November 7, 2026
  20. Md. Code, Bus. Occ. & Prof. § 12-501Maryland General AssemblyChecked November 7, 2026
  21. Plumbing board page plaffMaryland Department of Labor, State Board of PlumbingDated July 1, 2025Checked November 7, 2026
  22. COMAR 09.20.02.04Maryland Division of State Documents (COMAR)Checked November 7, 2026
  23. Plumbing board page plinsureMaryland Department of Labor, State Board of PlumbingChecked November 7, 2026
  24. Md. Code, Bus. Occ. & Prof. § 12-401Maryland General AssemblyChecked November 7, 2026
  25. Md. Code, Bus. Occ. & Prof. § 12-308Maryland General AssemblyChecked November 7, 2026
  26. Plumber Information and LicensesWSSC Water (Washington Suburban Sanitary Commission)Checked November 7, 2026
  27. Plumbing board page plcompfaqs (Complaint FAQs)Maryland Department of Labor, State Board of PlumbingChecked November 7, 2026