- MD-JP is the Maryland Board's combined Journey Plumber/Gas Fitter exam, administered by PSI Services LLC.
- Base exam: 100 questions, 240 minutes, 70% passing score under COMAR 09.20.02.03.
- PSI exam fee is $65; initial Journey license and renewal are $43.50 each under the July 1, 2025 fee schedule.
- Eligibility needs four years as a licensed apprentice, 7,500 hours under a Master, and an approved 32-hour backflow course.
What Is the MD-JP Certification?
MD-JP is the site shorthand used by MD-JP Exam Prep for the Maryland Journeyman Plumber License Exam - officially titled the Journey Plumber/Gas Fitter examination by the Maryland State Board of Plumbing. Candidates sometimes search for it as "journeyman plumber," but the underlying credential is one and the same: a state licensing exam that qualifies you to work independently as a journey-level plumber and gas fitter in Maryland. If you're still sorting out terminology, the companion pieces What Is MD-JP? and MD-JP Meaning walk through the naming conventions in more detail.
This article gives you the operational picture: who runs the exam, how registration and fees work, what the nine content domains cover, and what happens after you pass. For a deeper breakdown of preparation strategy, see the MD-JP Study Guide 2026.
Who Administers the Exam
Two entities matter here. The Maryland State Board of Plumbing, under the Maryland Department of Labor, sets eligibility rules, fees, and licensing policy. The actual computer-based test is delivered by PSI Services LLC, which publishes the official candidate information bulletin and manages test-day logistics, retest scheduling, and score reporting. Since March 31, 2025, all examination applications must be submitted online only - paper applications are no longer accepted for scheduling your test date.
Because two organizations are involved, candidates sometimes get confused about where to direct questions. Licensing eligibility, apprenticeship hours, and the backflow course requirement go through the Board; test scheduling, accommodations, and the day-of testing experience go through PSI. If you're new to this dual structure, What Is MD-JP Certification? covers it from the ground up.
Eligibility and Registration
Ordinary eligibility to sit for the exam requires:
- Four years as a licensed apprentice
- 7,500 hours of work under a licensed Master Plumber
- A current, approved 32-hour backflow-prevention device testing course
Up to 1,500 approved school hours can count toward the 7,500-hour experience requirement, which helps candidates coming from formal trade programs shorten their on-the-job clock. A full walkthrough of documentation and edge cases lives in MD-JP Requirements 2026.
| Item | Amount / Requirement |
|---|---|
| PSI examination fee | $65 per attempt |
| Initial Journey license | $43.50 |
| License renewal (biennial) | $43.50 |
| Apprenticeship experience | 4 years / 7,500 hours under a licensed Master |
| Backflow course | 32 hours, current Board-approved course |
For the full picture, including what's and isn't rolled into total out-of-pocket cost, see MD-JP Certification Cost 2026.
Exam Format and Scoring
The base MD-JP exam is 100 questions delivered as computer-based multiple choice, with a 240-minute time allowance. PSI may include five to ten additional unscored experimental questions embedded in the test; these come with extra time outside the base 240-minute allowance, so they shouldn't eat into your pacing for the scored content.
Passing requires a score of 70%, a figure confirmed both in the PSI candidate bulletin and in COMAR 09.20.02.03. That regulation is the authoritative source if you ever need to verify the number independently. For a plain-language breakdown of what 70% actually means in terms of questions you can miss, read MD-JP Passing Score 2026.
Key Takeaway
Don't let unscored experimental questions rattle you mid-exam - you can't identify them, so answer every question with the same care and keep your pace anchored to the 240-minute base allowance for the 100 scored items.
The Nine MD-JP Domains
The exam draws its 100 questions from nine content domains defined by the Board's official allocation. Gas Appliances and Piping carries the heaviest weight, followed by Drain, Waste, and Vent Systems and then Backflow Prevention - meaning these three areas deserve a disproportionate share of your review time relative to the other six.
Domain 8: Gas Appliances and Piping
As the largest domain on the exam, this area covers gas piping sizing, appliance connections, venting requirements, and shutoff placement. Because Maryland's exam is a combined Journey Plumber/Gas Fitter test, gas questions are not an afterthought - they're central.
- Expect the highest single-domain question count on test day
Domain 7: Drain, Waste, and Vent Systems
DWV sizing, slope, venting configurations, and fixture unit calculations show up heavily here. This domain overlaps with Domain 9 (Plumbing Mathematics), so weak math skills will cost you points in two places at once.
- Second-largest domain by question weight
Domain 6: Backflow Prevention
Given that a 32-hour backflow course is a licensing prerequisite, it's no surprise this domain carries substantial weight. Device types, installation clearances, and cross-connection scenarios are common question formats.
- Third-largest domain by question weight
The remaining six domains - Plumbing Fundamentals and Safety, Materials, Uses, and Specifications, Traps, Interceptors, and Backwater Valves, Plumbing Fixtures, Fixture Fittings, and Plumbing Appliances, Water Supply Systems, and Plumbing Mathematics - round out the remainder of the 100 scored questions. Each still requires solid command of code language and applied scenarios rather than rote memorization. For domain-by-domain study allocation and sample question styles, see the full MD-JP Exam Domains 2026 guide.
Open-Book References and Calculators
MD-JP is an open-book exam, but the rules around what counts as an "approved reference" are strict. You may bring permitted code references with permanent tabs and highlighting already in place. What's prohibited is just as important: handwritten notes, loose papers, and outside study guides inserted into your books are not allowed at the testing center.
Calculators are permitted but must be silent, nonprinting, and nonprogrammable, and cannot have an alphabetic keyboard. A basic four-function or scientific calculator that meets those specs is your safest bet - don't risk showing up with a device PSI proctors might reject at check-in.
Key Takeaway
Tab your reference books well before test day, not the night before. Permanent tabbing takes time to get right, and last-minute scrambling with sticky notes risks violating the "no added papers" rule.
Retesting and Getting Licensed
If you don't pass on your first attempt, Maryland allows a retest once every 30 days - plan your next attempt window accordingly rather than assuming you can rebook immediately. Once you do pass, you must apply for your license within one year of the passing exam date, so don't let paperwork lapse after clearing the hardest part.
License renewal is biennial. For an ordinary Journey license there's no routine continuing education requirement, though that changes if you pursue a plumbing inspector credential later, which carries its own separate CE obligations. Note also that WSSC and Baltimore County maintain separate licensing arrangements outside the standard statewide process, so double-check local requirements if you plan to work in those jurisdictions.
Curious how difficult the exam actually is relative to other trade licensing tests, or what recent pass-rate data shows? See How Hard Is the MD-JP Exam? and MD-JP Pass Rate 2026: What the Data Shows for context drawn directly from Board minutes.
Who Hires MD-JP Journey Plumbers
Holding a Maryland Journey Plumber/Gas Fitter license opens doors with residential and commercial plumbing contractors, mechanical contractors handling combined gas and water work, property management companies, and municipal or utility-adjacent employers that need licensed gas fitting capability alongside plumbing. Because the exam is a combined plumbing and gas fitting credential, license holders are often more versatile hires than plumbers licensed in jurisdictions that separate the two disciplines.
If you're evaluating whether the time and cost investment pays off relative to job opportunities and earning potential, MD-JP Salary Guide 2026 and Is the MD-JP Certification Worth It? dig into that question directly. For active listings and role types, MD-JP Jobs is a useful starting point.
Building a Domain-Based Study Plan
Generic study techniques only help if you point them at the right material. Given that Gas Appliances and Piping, Drain Waste and Vent Systems, and Backflow Prevention carry the most weight, your review calendar should front-load those three domains rather than splitting time evenly across all nine.
Heavy-Weight Domains
- Gas Appliances and Piping fundamentals and sizing
- Drain, Waste, and Vent Systems configurations and fixture units
- Backflow Prevention device types and installation rules
Supporting Domains
- Water Supply Systems and Plumbing Fixtures/Fittings
- Traps, Interceptors, and Backwater Valves
- Materials, Uses, and Specifications
Math and Fundamentals
- Plumbing Mathematics practice tied to DWV and gas sizing problems
- Plumbing Fundamentals and Safety review
- Timed practice using your permitted calculator only
Reference Tabbing and Simulation
- Finalize permanent tabs in your approved references
- Full 240-minute, 100-question timed simulation
- Review weak domains flagged by practice results
Run full-length practice sessions on MD-JP Exam Prep's practice platform to get comfortable with the pacing math: 240 minutes for 100 questions leaves a little over two minutes per question, tighter once you factor in flagged items you revisit. Repeated timed runs on our practice tests build the instinct for when to move on versus when a question is worth the extra time. For a condensed reference you can revisit the week before your exam, bookmark the MD-JP Cheat Sheet 2026.
Frequently Asked Questions
It's a combined Journey Plumber/Gas Fitter examination administered through the Maryland State Board of Plumbing, so gas fitting content - especially Gas Appliances and Piping, the largest domain - is fully in scope alongside plumbing topics.
The base exam is 100 questions with 240 minutes allotted. PSI may add five to ten unscored experimental questions with separate additional time outside that base allowance.
You need 70%, a figure confirmed by both the PSI candidate bulletin and COMAR 09.20.02.03.
No. The exam is open book with approved references only, using permanent tabs and highlighting. Handwritten notes, loose papers, and outside study guides are prohibited.
You can retest once per 30 days. Once you do pass, you must apply for your license within one year of the passing exam date to avoid needing to retest.
Understanding the mechanics behind MD-JP - the Board and PSI's respective roles, the nine domains and their weighting, the fee schedule, and the open-book rules - puts you in a far stronger position than generic exam prep advice ever could. Use the linked guides above to go deeper on any single piece, and keep the domain weighting front of mind as you plan your final weeks of review.