South Carolina Mechanical Contractor License

What the Mechanical Contractor License Actually Covers

Any commercial plumbing, HVAC, or mechanical project in South Carolina that exceeds $10,000 in combined labor, materials, and profit requires a Mechanical Contractor license from the Contractor's Licensing Board (CLB), a division of the Department of Labor, Licensing and Regulation (LLR). That threshold is set by S.C. Code Section 40-11-30 and includes the aggregate value of the entire project — not just your portion if you're subcontracting.

The license itself is issued to a business entity, not to an individual tradesperson. A sole proprietor, LLC, or corporation applies through the CLB, and the entity must designate a Primary Qualifying Party (PQP) who holds a current Master-level trade certification or has passed the state-level plumbing trade exam. The PQP is personally responsible for directing and supervising all work performed under that license number.

One detail that catches applicants off guard: the CLB follows a "test first, apply second" sequence. You register directly with PSI, pass both the Commercial Plumbing (PB) exam and the South Carolina Business Management and Law exam, and only then submit your license application. Attempting to file your application before passing both exams results in an immediate return of your paperwork.

The Five Financial Groups

The CLB structures mechanical contractor licenses into five groups based on project size limits. Each group requires the applicant to demonstrate a minimum net worth or working capital — or to post a surety bond in lieu of financials.

Group 1: Projects up to $35,000. Minimum net worth of $3,500 or a $7,000 surety bond.

Group 2: Projects up to $75,000. Minimum net worth of $7,500 or a $15,000 surety bond.

Group 3: Projects up to $150,000. Minimum net worth of $15,000. Financial statement must be compiled by a licensed CPA.

Group 4: Projects up to $300,000. Minimum net worth of $30,000. CPA-compiled financial statement required.

Group 5: Unlimited project value. Minimum net worth of $200,000 or a $300,000 surety bond. If relying on financial statements, a full CPA-audited balance sheet is required — income-tax-basis statements and internal bookkeeper reports are rejected.

For Groups 1 through 4, the required bond amount equals twice the group's net worth requirement. Group 5 is the exception: it uses a $300,000 bond for a $200,000 net-worth requirement. Most applicants targeting small to mid-size commercial work start at Group 1 or Group 2, where the bond premiums are modest and eliminate the need for CPA-prepared financial statements.

Experience and Exam Requirements

The CLB requires two years of commercial plumbing experience within the past five years, documented through notarized Work Experience Affidavits (Doc. 167). Each affidavit must detail hands-on commercial work and be signed by a licensed qualifier or supervisor who directly observed the applicant's work.

If a former supervisor is deceased or uncooperative, you'll need to find a licensed Mechanical Contractor willing to evaluate your skills, supervise you for a probationary period, and sign the affidavit based on direct observation. Up to one year of experience can also be substituted by completing a two-year technical degree in plumbing or mechanical technology from an accredited South Carolina institution.

The two PSI exams — Commercial Plumbing and Business Management and Law — are both open-book. The passing threshold is 70% on each portion. There are no board-imposed waiting periods for retakes; if you fail, you reschedule directly with PSI and pay the exam fee again.

The Full Application Sequence

Here's the chronological order that prevents rejected applications:

1. Accumulate two years of supervised commercial plumbing experience and secure notarized Doc. 167 affidavits from supervisors.
2. Register with PSI and pass both the Commercial Plumbing (PB) and Business Management and Law exams.
3. Register your business entity with the South Carolina Secretary of State ($110 for an LLC).
4. Obtain an EIN from the IRS and register with the South Carolina Department of Revenue via MyDORWAY for withholding and sales tax.
5. Prepare your financial statement or secure a surety bond for your chosen group.
6. Secure general liability insurance (minimum $100,000 coverage).
7. Submit Doc. 165 (General & Mechanical Contractor Application), Doc. 168 (PQP Certification Application), Doc. 167 affidavits, PSI pass sheets, and the $350 license fee to the CLB.

Fees at a Glance

The initial license application fee is $350. PSI exam fees run approximately $75 per portion ($150 total for both exams). If your PQP leaves and you need to transfer the qualifying party designation, Doc. 181 handles that process. Renewal occurs every two years — commercial mechanical contractor licenses expire on October 31 of odd-numbered years.

What the License Doesn't Include

Holding a Mechanical Contractor license authorizes your business entity to perform both commercial and residential plumbing work statewide. But it doesn't exempt you from local municipal permitting. Every jurisdiction where you pull permits — Charleston, Columbia, Greenville, Spartanburg — has its own business license requirements, permit fees, and inspection protocols that operate independently from the state license.

If you're navigating the full sequence from trade certification through business formation and your first permit pull, the South Carolina Plumber License Guide walks through every step for both the commercial CLB track and the residential RBC track.

See more South Carolina guides →