Mississippi does not license plumbers under a master or journeyman title. At the contracting tier, the Mississippi State Board of Contractors issues a Certificate of Responsibility with the PLUMBING classification for commercial work — earned when a firm’s designated qualifying party passes the required examinations — and a Residential Plumbing license on the residential track. Both tracks are examined by PSI on the 2021 International Plumbing Code, with a companion Law and Business Management examination, and each examination must be passed at 70 percent. The PassProfessor Mississippi program prepares qualifying parties and residential applicants for those PSI examinations.
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What this credential certifies
Start with the name, because it is the first thing generic material gets wrong. There is no Mississippi master plumber license and no Mississippi journeyman plumber license. The state’s top plumbing credential is a firm-level instrument: the Certificate of Responsibility, issued by the Mississippi State Board of Contractors to a person, firm, or entity, carrying the classifications that firm is authorised to bid and perform. PLUMBING sits under the major classification Mechanical Work in the commercial application, and holding a major classification covers its specialties. The certificate holder may bid and perform only the classifications printed on its certificate — the PLUMBING classification, not a personal title, is the thing being earned.
The residential track is separate. A Residential Plumbing license covers residential plumbing work, and a residential plumbing subcontractor needs that license on a residential project at any dollar amount. The commercial threshold is different in kind: a Certificate of Responsibility is required for commercial contracting at $50,000 or more. Mississippi examines a qualifying party on behalf of a firm, and licenses the firm.
Read the companion guide: Mississippi Plumbing Contractor Exam Guide.
The examinations at a glance
| Item | Verified position |
|---|---|
| Program | Mississippi Certificate of Responsibility with the PLUMBING classification (commercial) and Residential Plumbing license — the contracting tier |
| Regulator | Mississippi State Board of Contractors (MSBOC), under Miss. Code Ann. Title 31, chapter 3 for commercial work and Title 73, chapter 59 for residential licensure; rules at 30 Miss. Admin. Code Parts 802 and 803 |
| Who is examined | The firm’s designated qualifying party — an owner, officer, member of the executive staff, or responsible managing employee — sits the examinations on the firm’s behalf |
| Examination vendor | PSI Services LLC (PSI); Board approval comes first, and PSI confirms eligibility before a candidate can schedule |
| Companion examination | Law and Business Management: 50 questions / 2 hours / OPEN BOOK — mandatory for all commercial and residential applicants |
| Commercial trade examination | PLUMBING: 70 questions / 3 hours / OPEN BOOK, computer-administered |
| Residential trade examination | Residential Plumbing: 80 questions / 4 hours / OPEN BOOK |
| Passing standard | 70 percent on each examination — Law and Business Management, PLUMBING, and Residential Plumbing are each passed separately |
| Code tested | 2021 International Plumbing Code for both plumbing examinations |
| Practical | None. All Mississippi plumbing examinations are computer-administered multiple-choice examinations; Isometric Analysis is a written content area inside them, not a hands-on test |
| Board application fees | Commercial application $400, including one classification, plus $100 for each additional classification; residential application $50, including one classification, plus $100 per additional classification |
| PSI examination fees | $120 for one examination portion; $240 for two examination portions |
| Administrator note | PassProfessor is independent and is not affiliated with the Mississippi State Board of Contractors or with PSI |
Two examinations, not one: the companion every applicant sits
Every plumbing applicant in Mississippi sits two examinations. The first is the Law and Business Management examination, mandatory for all commercial and residential applicants alike: 50 questions in 2 hours, open book, built on the NASCLA Contractors Guide to Business, Law and Project Management — Mississippi, 6th Edition, operative since October 1, 2023. Its published outline runs from Licensing, Estimating and Bidding, and Contracts through Financial, Tax, and Labor Law to Risk Management and Environmental and Safety. A qualifying party who prepares only for pipe and code has prepared for barely half the sitting — 50 of the 120 questions a commercial plumbing applicant answers sit in this companion paper, and it carries its own separate 70 percent line.
The second examination is the trade paper, and here the two tracks divide. The commercial PLUMBING examination runs 70 questions in 3 hours, open book. The Residential Plumbing examination runs 80 questions in 4 hours, open book. Both are computer-administered through PSI, both test the 2021 International Plumbing Code, and both must independently reach 70 percent. Scores are given immediately on screen.
The commercial PLUMBING examination in detail
The commercial examination’s scope is stated in the PSI bulletin in one sentence candidates should memorise: unlimited commercial and residential plumbing, not including fuel gas or boiler systems. The reference list follows that scope exactly — the 2021 International Plumbing Code, the OSHA provisions at 29 CFR Part 1926, and Mathematics for Plumbers and Pipefitters, 8th edition — and no fuel gas code appears in it, because fuel gas is outside the commercial scope.
Its published outline sums to the full 70 questions: Drain, Waste, and Vent carries 15, the largest single block; Isometric Analysis 12; Water Supply 6; Fixtures and Equipment 5; and the remaining areas — regulations, safety, cleanouts, traps and interceptors, piping and controls, hangers, backflow, joints, water heaters, and developed length — complete the paper. Nearly two-fifths of the commercial paper is drainage, venting, and the isometric reading of a system on paper. Isometric Analysis here is analysis — reading a drawn system inside a multiple-choice examination — not a drawing test and not a bench project.
The Residential Plumbing examination is a different paper
Residential candidates should not borrow a commercial study plan. The residential paper is longer — 80 questions in 4 hours — and its scope runs the other way on fuel: where the commercial examination excludes fuel gas, the Residential Plumbing outline tests Fuel Gas for 5 questions, LP Gas for 3, and Fuel Oil for 2, with Piping carrying a further 5. Its references match: the 2021 International Plumbing Code, the Fuel Gas Code in its 2018 edition, and the International Residential Code, 2021. Drain, Waste and Vent and Sewers is its largest block at 17, followed by General Plumbing Knowledge and Regulations at 15 and Isometric Analysis at 9. Same state, same vendor, same code edition, same 70 percent standard — and a materially different examination.
Tested code: 2021 IPC — and no statewide adopted edition to lean on
Both plumbing examinations test the 2021 International Plumbing Code. For code questions, the examinations are based only on the listed editions, and only those editions may be brought into the testing site. That is the complete, publishable statement about the tested edition, and this program teaches to it.
What this page will not claim is a statewide adopted IPC edition for Mississippi, because none is verified. Mississippi’s framework runs through the Mississippi Building Codes Council, which adopts discretionary statewide minimum codes drawn from recent editions, while local governments adopt locally and may opt out within 120 days — an opt-out framework, not a single statewide book. Local editions in the record differ from place to place. In the examination room the question is simpler and fully settled: the tested edition is 2021, and answers come from it.
The qualifying party: how a firm gets examined
The qualifying-party system is Mississippi’s ladder, and it is a ladder of responsibility rather than of titled grades. The license or Certificate of Responsibility is issued to the person, firm, or entity. The qualifying party is the individual who takes the required examinations for that entity, and must be an owner, an officer, a member of the executive staff, or a responsible managing employee — regularly employed and actively engaged in the classification, with proof of employment such as a check stub, W-2, or Secretary of State listing; a sole proprietorship needs no such proof. One qualifying party may serve no more than three separate entities without Board permission. If the qualifying party leaves, the Board must be notified in writing immediately, and a new qualifying party must successfully complete the required examinations within 90 days — a deadline that turns an examination into an urgent business event for the firm left behind.
There is no fixed years-of-experience or hours requirement stated for either track. Instead, the statute makes experience and ability a Board consideration, and the application carries the substance: experience in the classifications requested, at least three jobs completed in the classification, and three reference letters, one from the bank. Commercial applicants also file a CPA reviewed financial statement from within the prior 12 months — a compilation is not accepted — show net worth of at least $50,000 for major classifications or $20,000 for other applicants, and carry general liability insurance of at least $300,000 per occurrence and $600,000 aggregate, with the Board as certificate holder. Neither track carries a license-level surety bond, and both run on a one-year term. Commercial Certificates of Responsibility carry no continuing education requirement; residential candidates should confirm current renewal duties with the Board for their specific license position.
Sitting the examinations: room rules and the retake window
Candidates bring their own references. References may be highlighted, underlined, and indexed before the session only; they may not be written in, tabs must be permanent, and no loose papers are allowed. A silent, non-printing, non-programmable calculator is permitted. Between 1 and 10 unscored experimental items — generally around ten percent — may be included in a sitting and count against examination time: not every question on screen is scored, and none announces itself.
The retake structure is a window, not a waiting period. A candidate has six months from the date of eligibility to take the examination, and may retest on an unlimited basis during that period. If the candidate does not pass within six months, the candidate must reapply with the Board. Cancelling or rescheduling without forfeiting the PSI fee requires notice two days before the scheduled date, through the website or by speaking to a PSI representative — voicemail is not acceptable — and PSI holds examination fees on file for one year from initial registration.
What makes this tier demanding
Mississippi’s contracting tier is demanding because it examines two competences and a business structure at once. The Law and Business Management companion is a full second discipline for a tradesperson whose day is pipe. The commercial paper weights drainage, venting, and isometric analysis heavily enough that a candidate strong on fixtures and supply can still fall short. The qualifying-party rules mean the person sitting is also carrying a firm’s authority, its three-entity limit, and its 90-day replacement exposure. And the two tracks genuinely differ — on fuel scope, on length, on references — so experience in one is not preparation for the other without deliberate translation.
What the PassProfessor program will cover
Built on the platform architecture: an International Plumbing Code foundation plus a Mississippi delta. The foundation is original practice material on the plumbing systems both Mississippi papers examine — drainage, waste, and venting; water supply; fixtures; traps, interceptors, and backflow; water heaters; and the developed-length and isometric work the outlines weight so heavily — worked against the 2021 International Plumbing Code, the edition Mississippi tests. The Mississippi delta is everything above: the Certificate of Responsibility and its PLUMBING classification, the qualifying-party system, the Law and Business Management companion and its published outline, the residential paper’s distinct fuel scope and references, the corroborated fee layers, and the six-month eligibility window. Every item is written from scratch against primary sources; no item is drawn from another provider’s material.
Business and law taught as an examination, not an appendix. Half of what a Mississippi plumbing applicant must pass is not plumbing. This program treats the NASCLA-based companion with the same seriousness as the trade paper — its outline areas and its own 70 percent line.
Independence, stated plainly. PassProfessor is an independent preparation provider, not affiliated with the Mississippi State Board of Contractors or with PSI, and this program is not a Board course. Completing it confers no certificate, no license, and no exemption; the Board alone issues Certificates of Responsibility and residential licenses, and candidates register for examinations through PSI after Board approval.
Tell me when enrollment opens. This program is in the works and enrollment is not yet open. Leave an email address and PassProfessor will write to you when the program is ready — and only about this program. No date is promised.
Frequently asked questions
Does Mississippi have a master plumber license?
No. Mississippi has no master plumber license and no journeyman plumber license. At the contracting tier, the Mississippi State Board of Contractors issues a Certificate of Responsibility with the PLUMBING classification for commercial work, and a Residential Plumbing license on the residential track.
Who actually sits the Mississippi plumbing examinations?
For a commercial Certificate of Responsibility, the firm’s designated qualifying party — an owner, officer, member of the executive staff, or responsible managing employee — sits the examinations on the firm’s behalf. The certificate itself is issued to the person, firm, or entity.
What examinations must a Mississippi plumbing applicant pass?
Two: the Law and Business Management examination (50 questions, 2 hours, open book), mandatory for all applicants, and a trade examination — PLUMBING for the commercial track (70 questions, 3 hours, open book) or Residential Plumbing for the residential track (80 questions, 4 hours, open book).
What score passes in Mississippi?
70 percent on each examination. Each examination is passed separately, and the rule layer states the same standard: a grade of at least 70 percent.
What code do the Mississippi plumbing examinations test?
The 2021 International Plumbing Code, for both plumbing examinations. For code questions, only the listed editions are examined and only those editions may be brought into the testing site.
Does the commercial PLUMBING examination test fuel gas?
No. Its stated scope is unlimited commercial and residential plumbing not including fuel gas or boiler systems, and no fuel gas code is in its reference list. The Residential Plumbing examination is the opposite: its outline includes Fuel Gas, LP Gas, and Fuel Oil.
Is there a practical or hands-on test in Mississippi?
No. All Mississippi plumbing examinations are computer-administered multiple-choice examinations. Isometric Analysis is a written content area inside them — 12 of 70 questions on the commercial paper and 9 of 80 on the residential paper — not a hands-on practical or a separate drawing test.
What do the examinations and applications cost?
Board application fees: commercial $400 including one classification, plus $100 per additional classification; residential $50 including one classification, plus $100 per additional classification. PSI examination fees: $120 for one examination portion and $240 for two portions, per registration.
What happens if I fail?
You may retest on an unlimited basis during your six-month eligibility period. If you do not pass within six months, you must reapply with the Board.
When does enrollment open?
The program is in the works; enrollment is not yet open. Leave an email address and PassProfessor will write to you when it is ready — only about this program.