Plumbing Contractor License in South Carolina: Requirements, Qualifier, Bond and Exams

Statewide — with the kind of work deciding which license a plumbing business needs.

A license is required for mechanical contracting when the total cost of construction is greater than $10,000 (raised from $5,000 by 2023 Act No. 69, effective May 19, 2023), and for plumbing that means the CLB's mechanical contractor license with the Plumbing (PB) subclassification.

Residential plumbing work exceeding $500 also requires a license — the Residential Builders Commission's Residential Plumber license.

Our research found no state journeyman plumber license in South Carolina — a finding from the pages we read, not a board statement — so at the state level it is the business that is licensed.

Two boards under SC LLR issue the licenses.

The Contractor's Licensing Board licenses mechanical contractors, and the mechanical classification includes the subclassifications Air Conditioning (AC), Heating (HT), Packaged Equipment (PK) and Plumbing (PB), among others — commercial plumbing contracting means the PB subclassification.

The chapter's Plumbing definition reaches the installation, replacement, alteration and repair of all plumbing, and a commercial plumbing contractor works under the same group limits, PQP rules, PSI exams, $350 fee and odd-year October 31 expiry as an HVAC contractor.

On the residential side, the Residential Builders Commission licenses the Residential Plumber specialty classification, and a residential builder licensed by examination may perform residential specialty work, including plumbing, without a separate specialty license.

The commercial license runs on a certified Primary Qualifying Party (PQP) for each classification: someone who passed the required exams and has at least two years of full-time experience in the classification within the past five years.

A qualifying party may serve as PQP for only one licensee — the exception is two entities at the same physical location where the QP works in both daily, earns a livelihood from both and owns at least 50% of one — so one qualifier cannot informally back two companies.

On the residential side, the RBC says work experience must be verified and approved before you are made eligible for the exam; our research did not establish the required hours.

PSI administers both exams a PQP needs: the technical exam for the classification, where one is required, and the PSI S.C. Business Management and Law for Commercial Contractors exam, passed at 70%.

For a plumbing contractor application the trade exam is the Plumbing (PB) classification's technical exam — commercial plumbing follows the same PSI exam rules as HVAC.

The CLB may waive the technical exam for applicants licensed in states with an exam-waiver agreement, but the pages we read did not include the board's agreement list, so ask the CLB before counting on a waiver.

The residential route has its own waivers: the Residential Plumber license can be obtained without the technical exam by holders of an SC mechanical Plumbing (PB) license held 1+ year by exam, a Mississippi or North Carolina license held 1+ year by exam, or a MASC/CAGC Master (Residential) Plumber certification.

The commercial license is backed by finances rather than a flat bond: each group pairs its per-job limit with a required net worth or working capital, and instead of a financial statement the contractor may post a surety bond equal to its group's net worth — $7,000 for Group 1 up to $300,000 for Group 5.

Residential specialty contractors, plumbers included, doing jobs over $5,000 for an individual property owner must file a surety bond in an amount approved by the Commission; our research did not verify the amount, and a licensed residential specialty contractor may hold no more than three classifications.

An insurance requirement did not appear in the pages we read — ask LLR what applies to your situation before you bid.

CLB general and mechanical contractor licenses cost $350 initially; mechanical contractor licenses expire October 31 of odd-numbered years and renew biennially for $135, with late fees of $100 to $200 extra.

The RBC's Residential Plumber license costs $220, renews for $220, and carries a $50 late fee and a $480 reinstatement fee; a license lapsed more than three years requires re-examination as a new applicant.

The statute the Commission administers says licenses renew annually, but our research could not confirm that cycle for the residential specialty licenses on the RBC's pages, so confirm your renewal date with the RBC before you rely on it.

Through exam waivers more than blanket reciprocity.

The CLB may waive the technical exam for an applicant holding a license in good standing in another state whose requirements are equal to or greater than the chapter's, and Ohio lists South Carolina among its HVAC and plumbing reciprocity states, with the business-and-law exam required under those agreements.

The CLB's own exam-waiver agreement list was not among the pages we read, so confirm the current list with the board before you rely on an out-of-state license.

On the residential side, the Residential Plumber technical exam can be skipped by licensees from Mississippi or North Carolina held 1+ year by exam, or holders of a MASC/CAGC Master (Residential) Plumber certification — the business management and law exam still applies.

Move fast and in writing: when the primary qualifying party disassociates from the licensee, the licensee or the PQP must notify LLR within 15 days of the disassociation.

The license stays in good standing for 90 days; if no replacement PQP is designated within those 90 days, it is suspended.

And because a qualifying party may serve only one licensee — outside the same-location ownership exception — you cannot keep working through someone else's qualifier.

Line up and certify a replacement inside the window, and file the 15-day notice on time.

Yes — the license requirement is tied to the value of the job.

Mechanical contracting requires the CLB license when the total cost of construction is greater than $10,000 — the level since May 19, 2023, when 2023 Act No. 69 raised it from $5,000.

Residential plumbing work exceeding $500 requires the Residential Plumber license.

On top of the thresholds sit the group caps on each job: Group 1 bids and jobs not to exceed $35,000 per job, up to Group 5's unlimited per-job limit.

A residential specialty contractor has a separate bond duty too: jobs over $5,000 for an individual property owner require filing a surety bond in an amount approved by the Commission.