Septic tank size by state / South Atlantic
South Carolina septic tank size
In South Carolina the minimum septic tank for a three-bedroom house is 1,000 gallons, and four bedrooms need the same 1,000 gallons. The figure comes from S.C. Code Regs. R.61-56 § 201.1(3). That matches the 1,000-gallon median of the 47 states listed here.
What the South Carolina rule says
The rule is S.C. Code Regs. R.61-56 § 201.1(3), administered by South Carolina Department of Environmental Services (SCDES; onsite program formerly under DHEC). In its own words:
No septic tank shall be installed which has a net liquid capacity of less than one thousand (1000) gallons. Such tanks shall be sufficient to serve dwellings of four (4) bedrooms or less. Two hundred fifty (250) gallons additional capacity shall be required for each bedroom over four (4).
Source: S.C. Code Regs. R.61-56 § 201.1(3), read 2026-10-20.
- Above four bedrooms the minimum rises 250 gallons per bedroom.
- The onsite program moved from DHEC to the new Department of Environmental Services in July 2024.
South Carolina minimum tank size by bedrooms
| Bedrooms | Minimum tank | Versus the median state |
|---|---|---|
| 1 | 1,000 gal | same |
| 2 | 1,000 gal | — |
| 3 | 1,000 gal | same |
| 4 | 1,000 gal | −200 |
| 5 | 1,250 gal | −250 |
| 6 | 1,500 gal | — |
The first step up comes at 5 bedrooms, from 1,000 to 1,250 gallons, and a six-bedroom house needs 1,500 gallons. Beyond the table the rule adds 250 gallons for each extra bedroom. These are minimums: the permit can call for more, and a bigger tank needs pumping less often.
How South Carolina compares with nearby states
Delaware requires 1,000 gallons for three bedrooms; Florida requires 900 gallons for three bedrooms; Georgia requires 1,000 gallons for three bedrooms; Maryland requires 1,000 gallons for three bedrooms; North Carolina requires 1,000 gallons for three bedrooms; Virginia requires 900 gallons for three bedrooms; West Virginia requires 1,000 gallons for three bedrooms. 37 of the 47 states listed here share South Carolina's three-bedroom figure.
Before you size a tank in South Carolina
- Bedrooms, not people, set the size in most rules. Rooms that could be used as bedrooms are usually counted, so check how your permitting office counts a den or a finished basement.
- Garbage disposals, grinder or ejector pumps and large tubs change the answer in many states; the points above list South Carolina's adjustments.
- The tank is only half the system. The drainfield is sized separately from soil tests, and it is usually the bigger cost.
- A private well on the same lot has its own setbacks from the tank and field; the well pump and pressure tank calculators size the water side.
Figures are the state's minimum as written on 2026-10-20. Local health departments can require more; the permit issued for your property governs. See the methodology for how each state was read.