- Exam Format at a Glance
- Fees and Registration Numbers
- Eligibility Snapshot
- Domain-by-Domain Item Counts
- Highest-Value Domains to Master
- Test-Day Rules and Allowed Tools
- Retakes, Validity Periods, and Veteran Credit
- Licensing and Renewal After You Pass
- A Final-Week Review Plan Built Around the Domains
- FAQ
- Part I (Written) has 80 questions in 160 minutes; Part II (Practical) has 40 questions in 160 minutes - never mix the time budgets.
- You need 70% on each part separately; a strong Part I score cannot offset a weak Part II score.
- Gas Piping, Equipment, and Appliances is the single largest Part I domain at 21 of 80 items.
- Isometric Analysis carries 20 of the 40 Part II items - half the practical exam.
Exam Format at a Glance
The Massachusetts Master Plumber License Exam, administered through PSI Services LLC under the Massachusetts Board of State Examiners of Plumbers and Gas Fitters, is split into two independently scored and timed sections. This is the single most important structural fact to internalize before you build a study plan, because the two parts do not share time or scoring:
- Part I - Written: 80 questions, 160 minutes
- Part II - Practical: 40 questions, 160 minutes
Combined, that's 120 questions across 320 minutes - but treat that total as a reference number only, not a pooled allowance. You cannot borrow time from Part I to finish Part II. Both parts are closed-book, computer-generated exams, and both require a 70% minimum score to pass. For a deeper walkthrough of how each content area is weighted, see the MA-MP Exam Domains 2026 guide, and for the exact scoring mechanics behind that 70% threshold, check the MA-MP passing score breakdown.
Fees and Registration Numbers
Budget for three separate line items, not one bundled "exam fee":
- Application fee: $31
- Examination administration fee: $80 for an initial attempt or any retake
- Initial license fee: $78 (paid once you pass and are ready to be licensed)
The online application also requires experience and education verification, a notarized CORI acknowledgement, and a passport-style photo before the Board approves you to sit for the exam. For a full cost breakdown including how renewal fees factor into your long-term investment, see the MA-MP Certification Cost breakdown.
Key Takeaway
Retaking either part costs the same $80 administration fee as an initial attempt - there is no discounted retake rate, so it pays to prepare thoroughly for whichever part you sit first.
Eligibility Snapshot
Before you can register, you need:
- A current Massachusetts journeyman plumber license
- At least one year and 1,700 hours of qualifying work performed as a licensed journeyman
- Completion of the Board-approved 110-hour Tier Five education requirement
If you already completed Tier Five education during your apprenticeship, you do not need to repeat it for the master-level application. This eligibility chain is detailed further in the MA-MP Requirements guide, which is worth reviewing before you submit your online application.
Domain-by-Domain Item Counts
Sixteen domains split across the two parts. Domains 1 through 12 live in Part I; domains 13 through 16 live in Part II. Memorize the item counts below - they tell you exactly where your study hours should go.
| Domain | Topic | Items | Part |
|---|---|---|---|
| 1 | General Regulations, Inspections, and Permits | 9 | I |
| 2 | Gas Piping, Equipment, and Appliances | 21 | I |
| 3 | Venting | 12 | I |
| 4 | Traps and Cleanouts | 2 | I |
| 5 | Fixtures, Equipment, and Clearances | 2 | I |
| 6 | Water Heaters | 3 | I |
| 7 | Piping, Valves, and Controls | 3 | I |
| 8 | Water Supply | 6 | I |
| 9 | Hangers and Supports | 2 | I |
| 10 | Drain, Waste, and Vent | 13 | I |
| 11 | Separators, Interceptors, and Grease Traps | 5 | I |
| 12 | Joints and Connections | 2 | I |
| 13 | Isometric Analysis | 20 | II |
| 14 | General Trade Calculations | 5 | II |
| 15 | Gas Piping | 7 | II |
| 16 | Gas Venting | 8 | II |
If you want the narrative behind each of these sixteen areas - what specific code sections and scenarios they test - the complete domains guide goes deeper than a quick reference table can.
Highest-Value Domains to Master
Domain 2: Gas Piping, Equipment, and Appliances
At 21 of 80 Part I items, this is the largest single domain on the written exam - more than a quarter of Part I. Candidates must be fluent with gas code references including NFPA 54 (National Fuel Gas Code, 2012 edition) and NFPA 58 (Liquefied Petroleum Gas Code, 2011 edition), plus the applicable sections of 248 CMR.
- Sizing and sectioning of gas piping systems
- Appliance venting and clearance requirements
- LP-gas installation distinctions from natural gas systems
Domain 13: Isometric Analysis
On the practical side, Isometric Analysis is worth 20 of 40 items - exactly half of Part II. Expect to read and interpret isometric drawings, trace pipe runs, and identify code violations or missing components directly from the diagram.
- Reading fixture, vent, and drain relationships on an isometric
- Spotting improper slope, missing cleanouts, or trap arrangement errors
- Cross-referencing drawing details against 248 CMR requirements
Domain 10: Drain, Waste, and Vent
At 13 of 80 items, DWV is the third-heaviest Part I domain behind Gas Piping and Venting (12 items). Sizing, fixture unit loading, and venting configurations all live here.
- Fixture unit calculations for drain and vent sizing
- Horizontal and vertical piping arrangement rules
- Interaction between DWV sizing and the separate Venting domain
Together, Gas Piping (21), Drain Waste and Vent (13), and Venting (12) account for 46 of the 80 Part I questions - well over half the written exam. On the practical side, Isometric Analysis alone is half of Part II. If you're trying to gauge overall difficulty before committing study hours, the difficulty guide breaks down why these particular domains trip up candidates most often.
Test-Day Rules and Allowed Tools
Both parts are closed-book, computer-generated exams administered by PSI. Know exactly what you can and can't bring:
- Not permitted: Reference books of any kind, including the code books themselves
- Permitted: A silent, non-printing, non-programmable battery calculator without alphabet keys
- Provided by PSI: Scratch paper for calculations and isometric sketching
Because no reference material is allowed in the testing center, every code citation you'll need - 248 CMR 10.00-10.23 (Massachusetts Uniform State Plumbing Code, 2023 edition), the referenced 2021 and 2014 sections of 248 CMR, NFPA 54, NFPA 58, and MGL Chapter 142 - has to already be committed to memory or internalized through practice before exam day.
Retakes, Validity Periods, and Veteran Credit
Master-level attempts are unlimited under the current PSI bulletin (dated October 3, 2025), which removes the pressure of a hard attempt cap. Two policies matter most for planning your retake strategy:
- A passing part remains valid for one year. If you pass Part I but fail Part II, you only need to retake Part II within that window - you don't have to repeat the part you already passed.
- Eligible veterans receive a five-percent examination credit upon submission of DD214 documentation, per the bulletin's stated policy.
Each retake still carries the full $80 administration fee, so treat every sitting - first attempt or retake - as if it's your only shot. The MA-MP Pass Rate page discusses what the available data shows about how candidates perform across both parts.
Key Takeaway
Because a passed part holds for one year, it's strategically sound to schedule the part you feel less confident about first - you can lock in the stronger part later without losing your progress.
Licensing and Renewal After You Pass
Once you pass both parts and pay the $78 initial license fee, your license is managed through the eLIPSE system. Renewal happens on a biennial cycle:
- Renewal deadline: May 1 of even-numbered years
- Renewal fee: $78 for master plumbers
- Continuing education: 12 hours of Board-approved coursework per two-year cycle
Plan your CE hours early in each cycle rather than scrambling near the May 1 deadline. Employers across residential, commercial, and municipal plumbing contracting in Massachusetts look for the master license specifically because it signals you've cleared both the experience threshold and this two-part exam - a distinction worth understanding if you're evaluating whether pursuing the credential fits your career goals, covered in the ROI analysis and the salary guide.
A Final-Week Review Plan Built Around the Domains
Rather than a generic study calendar, structure your last stretch of prep around the item-count table above. The goal is to spend time in proportion to how many questions each domain actually carries.
Attack the heaviest Part I domains
- Gas Piping, Equipment, and Appliances (21 items) - review NFPA 54 and NFPA 58 sizing rules
- Drain, Waste, and Vent (13 items) - redo fixture unit and sizing problems
- Venting (12 items) - cross-check against 248 CMR references
Clear the mid-weight Part I domains
- General Regulations, Inspections, and Permits (9 items)
- Water Supply (6 items)
- Separators, Interceptors, and Grease Traps (5 items)
Focus entirely on Part II
- Isometric Analysis (20 items) - practice reading and marking up drawings by hand
- Gas Venting (8 items) and Gas Piping (7 items) - rework trade/gas calculations without a code book
- General Trade Calculations (5 items) - time yourself using only a basic calculator
Simulate real conditions
- Take a full-length timed practice run on the practice test platform to feel the 160-minute pacing for each part
- Review missed items only in the six lightest Part I domains (2-3 items each), since they need recognition, not deep mastery
This is the one place generic study methodology matters here: batching your remaining hours by domain weight, rather than reviewing every domain equally, is the difference between broad familiarity and exam-ready recall on the topics that actually decide your score. For a fuller multi-week version of this approach, see the MA-MP Study Guide, and confirm your seat availability using the exam dates and scheduling guide before locking in a final review week.
FAQ
No. Part I and Part II are scored independently, and a passing part stays valid for one year. You can schedule them separately as long as both are completed within that validity window.
You need at least 70% on Part I and at least 70% on Part II. These are scored separately, so a high score on one part does not compensate for a low score on the other.
No. Both parts are closed-book. You may bring a silent, non-printing, non-programmable calculator without alphabet keys, and PSI will provide scratch paper.
Master-level attempts are unlimited under the current bulletin. Each attempt or retake carries the $80 examination administration fee, and you only need to retake the specific part you failed.
Eligible veterans receive a five-percent examination credit after submitting DD214 documentation, as outlined in the current PSI bulletin.