Septic Tanks - Commercial Builder

Incorrectly installed septic systems can harm water quality and make people sick, which is why South Carolina law requires site approvals and permits for all septic systems. 

If you are planning to build a commercial facility (restaurant, laundry mat, etc.) not served by a public or community sewer system, you must first obtain DHEC's approval and permits to install septic systems. Without these permits, your county will not be able to issue you building permits.

Before you buy land, call your local government to determine water and sewer availability. DHEC provides tips on choosing land suitable for septic systems and residential wells.

The Permitting Process and How to Apply

Any septic system with daily flow greater than 1,500 gallons per day is considered a large system. Large septic systems must meet all the requirements of System Standard 150 (Appendix B of Regulation 61-56), in addition to the general requirements listed in Reg. 61-56. Large septic systems must have at least a 36-inch area between the naturally occurring soil surface and the zone of seasonal saturation. Large septic systems must meet more stringent setbacks to wells and surface waters than residential systems. These systems are required to be designed by a Professional Engineer, licensed in the State of SC. Large systems require a 50% repair area.

Food Service Facility Systems

Any food service facility permitted by DHEC that is served by a septic system that was permitted after May 23, 2008, is required to comply with regulations regarding grease traps (SC Code Ann. Regs. 61-56, Section 201.2). Food service facilities permitted prior to May 23, 2008, will be required to comply with regulations regarding grease traps (4 SC Code Ann. Regs. 61-56, Section 201.2) if they experience a Septic System malfunction. Food service facility requiring a grease trap must provide separate plumbing stub-outs for restrooms (discharge to the septic tank) and food preparation areas (discharge to grease trap). All grease traps must be directly accessible from the ground surface. Owners of food service facilities must ensure that grease traps are cleaned frequently to avoid grease reaching the drainfield. No grease trap shall be less than 1000 gallons in size. The additional volume may be required depending upon the amount of input into the Septic System.

Find a Professional

There are times when you may need to hire an onsite wastewater (septic tank) professional. These professionals may be tank manufacturers, installers, pumpers/haulers, or professional soil classifiers.

Contracting with DHEC to perform Site and Soil Evaluations

DHEC’s Onsite Wastewater Program is now allowing qualified contractors to perform soils evaluations for the issuance of Onsite Wastewater Permits to Construct. The contracting rate will be no more than three times the Department’s permitting fee per site. If you are interested in this program and you meet the qualifications spelled out in Regulation 61-56, Section 102.1 (2)(c), please submit your resume and/or CV and qualifications to David Vaughan, Director of Onsite Wastewater, or 803-896-8657.

When Do I Need to Contact a Professional Soil Classifier?

You must contact a Professional Soil Classifier if any of the following scenarios apply to you:

  1. Your lot has been evaluated by the Department and it will not pass for a conventional septic system.
  2. Your lot is located within a subdivision consisting of ten or more lots. To learn more about the permitting of subdivisions consisting of ten or more lots, visit our Permits, Licenses, and Reports page.

You may also contact a PSC to conduct a soil evaluation on your property before submitting an application to the Department. The soil report can then be submitted with the application. This option should reduce the amount of time it takes to process your application.

Where can I find a list of Professional Soil Classifiers (PSCs)?

The SC Department of Labor, Licensing and Regulation (SC LLR) licenses PSCs. A list of licensed PSCs can be found by visiting

Forms Used by Professional Soil Classifiers

Septic Contractors

If you need to find a septic contractor (e.g., installer, pumper/hauler, or tank manufacturers), you can use this application as a resource.