- Exam Format: What's Actually on the PSI Screen
- Registration, Fees, and Eligibility Mechanics
- The 9 Domains: Where to Put Your Study Hours
- Reference Materials and What You Can Bring In
- A Study Timeline Built Around MD-JP's Structure
- Retesting, Licensing, and What Happens After You Pass
- Frequently Asked Questions
- The exam is 100 scored questions in 240 minutes, plus possibly 5-10 unscored PSI pretest items.
- Passing score is 70%, set under COMAR 09.20.02.03 and confirmed by the PSI candidate bulletin.
- Gas Appliances and Piping is the largest of the nine domains, followed by Drain, Waste, and Vent Systems and Backflow Prevention.
- Applications must be submitted online through PSI starting March 31, 2025 - no paper option.
Exam Format: What's Actually on the PSI Screen
The official Maryland State Board of Plumbing exam that most people search for as "MD-JP" is formally the Journey Plumber/Gas Fitter examination, administered on computer through PSI Services LLC. If you've never sat a PSI-delivered licensing exam before, the format is worth understanding before you crack open a single code book.
You'll answer 100 scored, multiple-choice questions with a 240-minute time limit. PSI may also insert five to ten additional unscored experimental questions - these are used to field-test future exam content, and PSI provides extra time outside your base 240 minutes to accommodate them. You won't know which questions are experimental, so the practical strategy is simple: treat every question on screen as if it counts.
For a deeper walkthrough of how the passing threshold is calculated and why it matters for pacing, see our dedicated breakdown in MD-JP Passing Score 2026: Exactly What You Need to Pass.
Registration, Fees, and Eligibility Mechanics
Under the Board's fee schedule effective July 1, 2025, the PSI examination fee is $65. If you pass and move forward with licensure, the initial Journey license and each biennial renewal run $43.50. These numbers matter for budgeting your first attempt, and they're the actual figures - not estimates from a different state's plumbing exam or an unrelated certification that happens to share the same initials.
Since March 31, 2025, the PSI bulletin has required all examination applications to be submitted online - there is no paper application path anymore. Before you can even schedule a seat, you need to satisfy Maryland's eligibility requirements:
- Four years working as a licensed apprentice
- 7,500 hours of experience under a licensed Master Plumber
- A current, approved 32-hour backflow-prevention device testing course
Up to 1,500 hours from an approved plumbing school can count toward that 7,500-hour experience requirement, which can meaningfully shorten the calendar time to eligibility for candidates who combined classroom training with fieldwork. For the full eligibility checklist, including how WSSC and Baltimore County handle licensing separately from the statewide Board, see MD-JP Requirements 2026: Eligibility, Prerequisites & How to Qualify.
If you're trying to budget the entire path - course fees, exam fee, license fee, and renewal cycle - our MD-JP Certification Cost 2026: Complete Pricing Breakdown article lays out the full cost picture using the current Board fee schedule.
The 9 Domains: Where to Put Your Study Hours
The Journey Plumber/Gas Fitter exam is built from nine official content domains, each drawing a set share of the 100 scored questions. Studying without knowing this weighting is like preparing for a test without knowing which chapters the professor emphasizes - you'll waste hours on low-yield material while underprepping the sections that decide your score.
According to the official allocation, Gas Appliances and Piping is the single largest domain on the exam, with Drain, Waste, and Vent Systems and Backflow Prevention following as the next-largest content areas. That ordering alone should reshape how you divide your study calendar.
Domain 8: Gas Appliances and Piping
As the largest domain, this area covers gas piping sizing, appliance venting, shutoff requirements, and connection methods. Because Maryland's combined exam title explicitly includes "Gas Fitter," expect this content to be tested in real depth, not as an afterthought.
- Gas pipe sizing and material selection
- Appliance connection and venting requirements
- Shutoff valve placement and testing
Domain 7: Drain, Waste, and Vent Systems
DWV design questions test your understanding of slope, venting configurations, cleanout placement, and trap arm limitations. This is core rough-in knowledge that experienced journeyman-track apprentices should already know from fieldwork - the exam simply formalizes it.
- Vent sizing and configuration rules
- Cleanout requirements and access
- Trap arm length and slope limits
Domain 6: Backflow Prevention
Given that eligibility itself requires a 32-hour backflow-prevention device testing course, it's no surprise this domain carries substantial weight. Expect questions on device types, installation clearances, and cross-connection scenarios.
- Backflow preventer types and applications
- Cross-connection control principles
- Installation and clearance requirements
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 exam and still deserve focused review, even though they carry smaller individual shares. For an item-by-item breakdown of every domain with study priorities for each, read MD-JP Exam Domains 2026: Complete Guide to All 9 Content Areas.
Key Takeaway
Don't split study time evenly across nine domains. Weight your hours toward Gas Appliances and Piping, Drain Waste and Vent Systems, and Backflow Prevention first, then round out the smaller domains in your final review pass.
Reference Materials and What You Can Bring In
The MD-JP exam is open book, but "open book" comes with strict limits that trip up unprepared candidates. You're allowed approved references with permanent tabs and highlighting already in place. What's prohibited is just as important: handwritten notes, loose added papers, and outside study guides are not permitted in the testing room.
The current public PSI bulletin, dated September 1, 2024, lists the 2018 IPC and 2018 IFGC as reference editions. However, the Board's June 2026 minutes discuss a 2024-code examination update, so the assigned code editions may be in transition. Before you invest in physical code books, confirm the exact reference editions directly with PSI - don't assume last year's list still applies on your test date.
Because Plumbing Mathematics is one of the nine tested domains, having a compliant calculator and knowing how to navigate your tabbed code book quickly under time pressure are both part of exam readiness, not just administrative details.
A Study Timeline Built Around MD-JP's Structure
Generic study techniques - spaced repetition, timed practice blocks, teaching concepts back to yourself - work well, but only when they're mapped to the actual weight of MD-JP's domains rather than applied evenly across every topic. Here's a way to sequence a multi-week plan around the domains that carry the most questions.
Gas Appliances and Piping + Backflow Prevention
- Work through gas sizing tables and appliance venting scenarios repeatedly
- Review backflow device types tied to your 32-hour course material
- Take timed practice sets isolated to these two domains
Drain, Waste, and Vent Systems + Water Supply Systems
- Drill vent sizing, cleanout placement, and slope requirements
- Practice water supply pipe sizing and fixture unit calculations
- Mix in Plumbing Mathematics problems since they overlap heavily here
Remaining Domains + Full Simulations
- Cover Fundamentals and Safety, Materials, Traps and Interceptors, and Fixtures
- Run full 100-question, 240-minute practice exams under real time constraints
- Review your compliant calculator use and code book tabbing speed
If you're unsure how difficult this exam actually is relative to the time you're investing, our analysis in How Hard Is the MD-JP Exam? Complete Difficulty Guide 2026 walks through the format and content demands in more detail. And for a fast final review the week of your test, the condensed MD-JP Cheat Sheet 2026: One-Page Review of Must-Know Facts hits the highest-yield points across all nine domains.
| Exam Detail | Figure |
|---|---|
| Scored questions | 100 |
| Time limit | 240 minutes |
| Unscored experimental items | 5-10 (extra time provided) |
| Passing score | 70% |
| PSI exam fee | $65 |
| Initial/renewal license fee | $43.50 each |
| Retest waiting period | 30 days |
Retesting, Licensing, and What Happens After You Pass
If you don't pass on your first attempt, Maryland allows you to retest once every 30 days - plenty of time to target the specific domains where you struggled rather than re-cramming everything from scratch. Use your score report to identify weak domains and rebuild a shorter, targeted study block before scheduling again.
Once you do pass, you must apply for your license within one year of the passing exam date. Miss that window and you may need to revisit eligibility requirements again, so don't treat the passing certificate as the finish line - the license application is a separate, time-sensitive step.
After licensure, the ordinary Journey license renews on a biennial cycle, and there's no routine continuing education requirement to maintain it - a detail that differs from many other trade licenses. Note that plumbing inspector CE is a separate track entirely, and that WSSC and Baltimore County maintain their own licensing arrangements independent of the statewide Board, which matters if you plan to work in those jurisdictions.
Curious who actually hires journeyman plumbers holding this license, or whether the investment pays off relative to the fees and hours required? Our MD-JP Salary Guide 2026: Complete Earnings Analysis and Is the MD-JP Certification Worth It? Complete ROI Analysis 2026 articles cover the career side, while MD-JP Jobs looks at where licensed journeyman plumbers find work across Maryland. If you're still mapping out testing windows and deadlines, check MD-JP Exam Dates 2026: Testing Windows, Deadlines & Scheduling before you lock in a study schedule.
New to the credential entirely? Start with What Is MD-JP? or MD-JP Meaning for the basics, and once you're ready to test your knowledge, head over to our practice test platform to see where you stand against real domain-weighted questions.
Frequently Asked Questions
The base exam has 100 scored multiple-choice questions with a 240-minute time limit. PSI may add 5-10 unscored experimental questions, with additional time provided outside the base 240 minutes.
You need 70% correct, a threshold set under COMAR 09.20.02.03 and confirmed in the PSI candidate bulletin.
No. The exam is open book with approved references that have permanent tabs and highlighting, but handwritten notes, added papers, and outside study guides are prohibited.
Gas Appliances and Piping is the largest of the nine domains, followed by Drain, Waste, and Vent Systems and Backflow Prevention - prioritize these three before spreading time across the remaining domains.
You can retest once every 30 days. If you pass, you must then apply for your license within one year of the passing exam date to avoid losing that eligibility window.