South Carolina examines plumbing contractors through two distinct state programs that are never blended: the commercial Mechanical Contractor license, Plumbing subclassification, issued to a business entity through its examined qualifying party, and the Residential Plumber license, a Residential Specialty Contractor credential held by an individual. Both programs test through PSI Services LLC, all portions are open book, and each carries its own technical examination, its own Business and Law examination, and its own published passing standard. The PassProfessor South Carolina Mechanical Contractor — Plumbing (Qualifying Party) program prepares candidates for those examinations, program by program.
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What this program covers — and what South Carolina does not license
South Carolina has no statewide master plumber license and no statewide journeyman plumber license; neither exists in the chapters that govern plumbing contracting. What the state does license, and examine, are the two programs this page covers.
The first, and the top tier, is the Mechanical Contractor license with the Plumbing subclassification, administered by the Contractor’s Licensing Board under Title 40, Chapter 11. It is an entity license: the license belongs to the business, and the individual who sits the examinations is the qualifying party, who holds a qualifying-party certificate on the firm’s behalf. The second program is the Residential Plumber license, administered by the Residential Builders Commission under Title 40, Chapter 59 — a Residential Specialty Contractor credential held by an individual licensee, examined on residential work only. The two programs have different boards, different technical examinations, different Business and Law examinations built on different study volumes, different experience gates, and different retake rules, so this program — and its companion guide at /south-carolina-master-plumber-exam-guide/ — keeps every fact attached to the program it belongs to.
A third name must be placed exactly. The Master Plumber Certification, issued by the Municipal Association of South Carolina through December 2025 and by Carolinas AGC from January 1, 2026, is a private certification, not a state license and not a PSI examination, accepted in both programs only as a waiver of the technical examination. It confers no right to contract on its own.
The examinations at a glance
| Item | Verified position |
|---|---|
| Program covered | South Carolina Mechanical Contractor — Plumbing (Qualifying Party), with the Residential Plumber program covered separately and never blended |
| Commercial authority | Contractor’s Licensing Board, Title 40, Chapter 11, within the Department of Labor, Licensing and Regulation |
| Residential authority | Residential Builders Commission, Title 40, Chapter 59 |
| Commercial examinations (qualifying party takes both) | Plumber technical: 80 questions, 4 hours, open book; Business Management and Law for Commercial Contractors: 50 questions, 125 minutes, open book |
| Residential examinations (licensee takes both) | Residential Plumbing: 65 questions, 180 minutes, open book; Business Management and Law for Residential Builders: 50 questions, 120 minutes, open book |
| Administrator | PSI Services LLC for both programs; all portions computer-administered and open book |
| Code editions tested | Dual-edition window: 2021 or 2024 editions; only the 2024 editions after July 1, 2027 |
| Administrator note | PassProfessor is independent and is not affiliated with the Contractor’s Licensing Board, the Residential Builders Commission, the Department of Labor, Licensing and Regulation, or PSI |
Passing standards are published in different forms for the two programs and are stated in full, in those forms, below. No single figure describes both programs.
Program one: the commercial Mechanical Contractor, Plumbing subclassification
The commercial license lets a business take plumbing work at a total cost greater than $10,000. Its statutory scope covers installation, replacement, alteration, and repair of plumbing solely within property lines — except water-meter and sewer-tap connections as allowed by the utility owner — including water-supply piping, fixtures and appliances, venting and sanitary drainage, roof leaders, water-conditioning equipment, pool piping, and gas lines necessary for gas-fired equipment, including solar water heating within that scope.
The license is issued in groups 1 through 5, capping a single job at $35,000, $100,000, $200,000, and $400,000, with group 5 unlimited, set by net worth of $7,000, $15,000, $30,000, $60,000, and $300,000, or working capital of $3,500, $10,000, $20,000, $40,000, and $200,000. A surety bond in lieu matches the net worth figure for the group.
Eligibility turns on experience, documented after the examinations: at least two years of commercial experience within the last five years in the classification sought, on an affidavit submitted after passing. A Primary Qualifying Party additionally verifies full-time employment for at least two years within the previous five years in the subclassification.
Program two: the Residential Plumber license
The Residential Plumber license covers residential specialty work exceeding $500, on structures of 16 units or less and not exceeding three stories. Its candidate follows the opposite sequence: at least one year of residential plumbing experience within the past five years is verified before eligibility, and only then does the candidate receive the Examination Eligibility Letter, valid for one year, that allows scheduling with PSI. Commercial candidates schedule first without pre-approval.
The residential examination is narrower in its references as well: no separate fuel gas code volume and no trade mathematics volume, both of which the commercial list carries.
One code window, three different dates
South Carolina candidates face three code dates that must be held apart.
Tested. Both PSI bulletins open a dual-edition window. Beginning November 1, 2026, a candidate may test on the 2024 International Plumbing Code, or the 2024 South Carolina Plumbing Code, or the 2021 International Plumbing Code, or the 2021 South Carolina Plumbing Code. After July 1, 2027, only the 2024 editions may be used. The same window governs the commercial fuel gas and residential residential-code references.
Adopted. The Building Codes Council — a third body, separate from both licensing boards — adopted the 2024 International Plumbing Code on August 26, 2025 as the 2024 South Carolina Plumbing Code, implemented January 1, 2027.
Enforced. Through December 31, 2026, the enforced code remains the 2021 International Plumbing Code with South Carolina modifications.
The consequence deserves emphasis: the examination keeps accepting the 2021 editions until July 1, 2027, six months past the January 1, 2027 implementation of the adopted 2024 code. Preparation must therefore be edition-aware: every code item in this program is keyed to the edition the candidate elects to test on, and the guide at /south-carolina-master-plumber-exam-guide/ works through the choice in full.
Inside the four sittings
All four portions are open book and computer-administered at PSI testing centres. Each bulletin allows 1 to 10 unscored experimental items, roughly ten percent, not scored but counted against the examination time; a commercial Plumber candidate may therefore see up to 90 questions, of which 80 are scored. Commercial candidates may test at most six hours per day, and cancelling or rescheduling requires two days’ notice given directly, not by voicemail or email.
The commercial technical examination carries a heavy isometric-analysis load: Drain, Waste and Vent Isometric Analysis 10 questions, Water Supply Isometric 4, Roof Drain Isometric 3 — 17 of 80 questions turn on obtaining information from isometric drawings. The residential examination likewise carries Isometric Analysis at 9 of 65. There is no hands-on practical and no drawing-production requirement in either program, and the commercial bulletin states that a ruler or scale is not required. Both tracks therefore carry a substantial isometric-analysis block.
The two Business and Law examinations must never be treated as one examination taken twice. The commercial examination is built on the NASCLA guide for South Carolina Commercial Contractors, 9th edition; the residential examination on the companion volume for South Carolina Residential Builders, 8th edition or 9th edition, 9th edition only from April 9, 2027. Outlines, durations — 125 minutes commercial, 120 minutes residential — and published passing forms all differ.
Passing standards, stated exactly as published
Each standard is printed here in its own published form, unmerged.
Commercial, as the bulletin publishes it. Plumber technical: “You will need to answer 56 questions correctly in order to pass” — 56 of 80. Commercial Business and Law: 35 correct of 50. The bulletin prints raw counts for these portions, not a percentage.
Commercial, as the statute states it. Separately, the statute at §40-11-230(A) requires “a grade of seventy percent or better” on both the technical examination and the South Carolina law examination — the statute’s own form of words.
Residential, as the bulletin publishes it. Residential Plumbing: 44 correct, printed as 44 correct (67.7%). Residential Business and Law: 34 correct, printed as 34 correct (68%). Both marks carry the bulletin’s printed hedge, in full: “(This passing score may change as examination performance is evaluated).”
No other passing figure is stated on this page, because no other form is the published form for these sittings.
Waivers: what the private certification does, and what it never does
South Carolina recognises defined routes that waive the technical examination. The Business and Law examination is never waived under any of them. In both programs, the Department accepts the private Master Plumber Certification — and, residentially, the Master Residential Plumber Certification — as a waiver of the technical examination only; Business and Law and the experience requirement still apply in full.
On the residential side only, two further routes are recognised: a current South Carolina Mechanical Contractor, Plumbing subclassification license held by examination for at least one year, or a North Carolina or Mississippi license held by examination for at least one year. No equivalent state list is published for the commercial waiver mechanism, and none is stated here.
Fees, renewal, and the cost layers kept separate
Examination fees are paid to PSI and are non-refundable and non-transferable: commercially $78 per portion; residentially $78 for one portion and $94 for both portions together.
Board fees sit on a separate layer. Commercially: initial fee $350, biennial renewal $135, late renewal additions of $100, $150, or $200 by lateness, and reinstatement on an initial application resubmitted at $350. Residentially: application $135, license $220, renewal $220, and late fee $50. On residential reinstatement, the regulation states a component of $260 while the agency and form layer states $480 as the total due — that $260 component together with the $220 renewal — components and total of the same event, not two competing fees. A firm Certificate of Authority, where required, carries a $100 fee and a $15,000 bond. No continuing education requirement applies to either credential covered here, and no general liability insurance minimum for these licensees is stated in the sources behind this page.
Retake rules also split by program. Commercial technical: two times in a 12-month period and thereafter only once in six months. Commercial Business and Law: without limit over a 12-month period. A passed examination may not be retaken. Residential: three attempts per 12 months, then a wait of 12 months from the last failure, with both portions to be passed within 12 months or the applicant must reapply.
What the PassProfessor program will cover
Two programs, two tracks, no blending. Our catalog now includes this program in two tracks mirroring the state’s structure: a commercial track for the qualifying party, including the group structure and financial showings, and a residential track for the individual licensee, on its own references and sequence. Material is never shared between tracks without being re-keyed to the correct bulletin, volume, and edition.
Edition-aware code preparation. Every code item is tagged to the bulletins’ window — 2021 or 2024 — so a candidate studies the edition they will actually open in the room.
Isometric analysis as a first-class block. With 17 of 80 commercial questions and 9 of 65 residential questions turning on isometric drawings, both tracks drill isometric reading as a core skill.
Independence, stated plainly. PassProfessor is an independent preparation provider, not affiliated with the Contractor’s Licensing Board, the Residential Builders Commission, the Department of Labor, Licensing and Regulation, or PSI. Completing this program confers no license, no certificate, and no waiver; the boards alone license. The full treatment is in the companion guide: /south-carolina-master-plumber-exam-guide/.
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 South Carolina license master plumbers or journeyman plumbers?
No. The examined state programs are the commercial Mechanical Contractor license, Plumbing subclassification, held by an entity through its qualifying party, and the individual Residential Plumber license.
Who is examined for the commercial license?
The firm’s qualifying party, who sits both commercial portions and holds the qualifying-party certificate; the license itself belongs to the business entity.
What are the commercial examinations?
Two open-book, computer-administered PSI portions: Plumber technical, 80 questions in 4 hours, and Business Management and Law for Commercial Contractors, 50 questions in 125 minutes.
What are the residential examinations?
Two open-book, computer-administered PSI portions, taken by the individual licensee: Residential Plumbing, 65 questions in 180 minutes, and Business Management and Law for Residential Builders, 50 questions in 120 minutes — different examinations from the commercial pair, built on a different NASCLA volume.
What score passes the commercial examinations?
As the bulletin publishes it: 56 questions correctly of 80 on Plumber technical, and 35 correct of 50 on commercial Business and Law. Separately, the statute at §40-11-230(A) requires “a grade of seventy percent or better” on both the technical examination and the South Carolina law examination.
What score passes the residential examinations?
As the bulletin publishes it: 44 correct (67.7%) on Residential Plumbing and 34 correct (68%) on residential Business and Law, each carrying the printed hedge: “(This passing score may change as examination performance is evaluated).”
Which code edition will I be tested on?
Your choice, inside the bulletins’ window: the 2021 or the 2024 editions through July 1, 2027, after which only the 2024 editions may be used. The adopted 2024 code is implemented January 1, 2027, while the 2021 code with South Carolina modifications remains enforced through December 31, 2026 — three dates for three layers.
Is the Master Plumber Certification a South Carolina license?
No. It is a private certification, issued by the Municipal Association of South Carolina through December 2025 and by Carolinas AGC from January 1, 2026, accepted only as a waiver of the technical examination in both programs. Business and Law and the experience requirements still apply.
Is there a hands-on practical in either program?
No. Neither program includes a hands-on practical or a drawing-production component. Both technical examinations test isometric analysis inside the written sitting — 17 of 80 questions commercially and 9 of 65 residentially — which this program drills directly.
What experience must a qualifying party show?
At least two years of commercial experience within the last five years in the classification sought, on an affidavit submitted after passing; a Primary Qualifying Party additionally verifies full-time employment for at least two years within the previous five years in the subclassification. Residential candidates show at least one year of residential plumbing experience within the past five years, verified before eligibility.
Is PassProfessor affiliated with the boards or with PSI?
No. PassProfessor is independent, not affiliated with either board, the Department, or PSI.
When does enrollment open?
The program is in the works and enrollment is not yet open. Leave an email address on this page and PassProfessor will write to you when the program is ready — and only about this program.