The Governing Framework

South Carolina onsite wastewater is regulated under:

• Regulation 61-56 — Onsite Wastewater Systems. Covers site conditions, primary treatment, tank capacity, setbacks, and installer licensing.
• R.61-56.200 — Minimum Site Conditions.
• R.61-56.201 — Minimum Requirements for Onsite Wastewater System Primary Treatment.
• South Carolina Department of Environmental Services (SC DES) — administers the regulation. DES was split from the former Department of Health and Environmental Control (DHEC) in 2024. Regulatory authority for onsite wastewater moved to DES in this reorganization.

Residential Septic Tank Capacity — R.61-56.201

For single-family residential systems, South Carolina uses a bedroom-based table with a 1,000-gallon floor:

No septic tank shall be installed with a net liquid capacity of less than 1,000 gallons. That 1,000-gallon floor serves dwellings of four bedrooms or less. Beyond four bedrooms, consult the specific capacity calculation in the regulation.

Commercial Septic Tank Capacity — Peak Flow Formula

For establishments other than individual dwellings (restaurants, offices, multi-family, schools), capacity is based on peak flow:

Setback Distances

Basement setbacks do not apply to septic tank/pump chamber location or where trench installations are downslope of the basement.

Permit Process

1. Contact your local DES environmental health office. DES operates regional offices across SC.
2. Site evaluation. Soil evaluation by licensed soil classifier or DES environmental health specialist.
3. Design submittal. Plot plan, soil evaluation results, system sizing, setbacks.
4. Permit issuance. Fees vary by county; typical range $300–$800. Timeline 3–8 weeks.
5. Licensed installer construction. SC DES licenses installers under R.61-56.
6. Inspection before backfill. Pre-cover inspection confirms tank, piping, dispersal, and setbacks.

Coastal and Regional Considerations

• Lowcountry (Charleston, Beaufort, Hilton Head): High water table, sandy soils, tidal influence. Mound systems and pressure dosing common. OCRM (Office of Ocean and Coastal Resource Management) setback coordination required near tidelands.
• Midlands (Columbia, Sumter): Sandhills and red clay transitions. Standard trench systems typical.
• Upstate (Greenville, Spartanburg): Piedmont red clay and steep slopes. Extended trench or alternative technologies common.
• Grand Strand (Myrtle Beach, Little River): Shallow groundwater, municipal service expanding. Many parcels that once permitted septic are now on sewer.
• Rural well-dependency: Much of SC uses private wells. The 75-foot well setback is often the binding constraint on small-lot parcels.

Frequently Asked Questions

Why does the search result still mention DHEC?

DHEC was split in 2024. Regulatory authority for septic moved to the Department of Environmental Services (DES). The regulation (R.61-56) did not change. Forms and older guidance may still reference DHEC; DES has preserved the transition links.

Can I install under 1,000 gallons for a tiny house or ADU?

No. R.61-56.201 sets 1,000 gallons as the floor for residential systems regardless of bedroom count. That's a hard minimum.

What about large commercial systems over 4,500 gpd?

Those require engineered designs and likely NPDES-style permits if surface discharge is contemplated. Contact DES and likely a consulting engineer at the design-flow planning stage.

Is there a state permit program for chemical storage tanks?

R.61-56 covers septic/wastewater, not chemical storage. For chemical tank compliance, the polyethylene chemical compatibility database covers manufacturer-level material selection — separate from state permitting.

Source Citations

• SC DES Septic Tanks Program
• Regulation 61-56 full text (PDF)
• R.61-56.201 Primary Treatment Requirements
• R.61-56.200 Minimum Site Conditions
• SC DES Residential Septic Tank Permits
• SC DES Commercial Septic Tank Permits

Agricultural Tank Regulations — SC Department of Agriculture & DHEC

The South Carolina Department of Agriculture (SCDA) and the SC Department of Health and Environmental Control (DHEC) share agricultural-tank oversight under the SC Code of Laws and SC Code of Regulations:

• 27 SC Code Regs R.27-1060 — SCDA Pesticides: applicator licensing, restricted-use pesticide (RUP) recordkeeping, bulk storage and repackaging.
• SC Code § 46-13-40 — statutory authority for the Pesticide Control Act.
• SC Code § 46-25 — Commercial Fertilizer regulations: registration, tonnage reporting, labeling (Clemson University Fertilizer Inspection program delegation).
• R.61-43 — DHEC Standards for the Permitting of Agricultural Animal Facilities: the dominant rule for hog and poultry CAFOs in South Carolina, covering manure storage tank design, land-application setbacks, mortality-management ponds, lagoon freeboard, and nutrient management plans.

South Carolina agriculture is hog-and-chicken intensive: swine finishing and farrow-to-finish operations concentrated in the Pee Dee and Lowcountry; commercial broiler and turkey houses across the Upstate (Anderson, Spartanburg, Pickens, Oconee), the Midlands (Newberry, Lexington, Saluda), and the Pee Dee (Darlington, Florence, Marlboro); egg-layer complexes in the Midlands. Under R.61-43 animal-waste storage structures above threshold (typically 500+ animal units for swine or large broiler/layer houses) require permitted manure storage tanks or lagoons with engineered liners, freeboard monitoring, annual sludge surveys, and Certified Animal Waste Manager oversight. The Pee Dee corn/cotton/soybean belt and Lowcountry timber/truck-farm region also run significant bulk liquid fertilizer (UAN-28/32, 10-34-0, ATS) and pesticide storage; retailers build containment pads to 110% of the largest tank with impermeable liners, rinsate recovery, and monthly walkthroughs. Coastal truck-farming counties add additional setback considerations in shellfish-growing-water basins.

Petroleum Storage Tanks (UST & AST) — DHEC

DHEC administers the South Carolina petroleum-tank program under the State Underground Petroleum Environmental Response Bank (SUPERB) Act with rules at R.61-92:

• R.61-92 SC Code Regs — Underground Storage Tank Control Regulations: design, installation, corrosion protection, spill/overfill prevention, release detection, operator training, closure, financial responsibility.
• SC Code Title 44 Ch. 2 — SUPERB Act (statutory authority, state trust fund for corrective action).
• R.61-9 Water Pollution Control Permits — NPDES and state-water pollution control permits; governs facility stormwater and discharge for AST sites.
• R.61-79 — Hazardous Waste Management Regulations (RCRA Subtitle C delegation).

South Carolina USTs register with DHEC, pay annual tank fees that feed the SUPERB Fund (which reimburses corrective-action costs), maintain 2018 federal upgrades (spill buckets, overfill prevention, operator ABC training, secondary containment for new tanks and piping), and report suspected releases within 24 hours. The SUPERB Fund historically covered a large share of UST cleanup costs in the state; registered tanks in good standing access the fund for eligible corrective action. DHEC's Underground Storage Tank Management Division runs registration, inspection, and compliance; the Division of Site Assessment, Remediation, and Revitalization handles post-release cleanup. Bulk petroleum terminals, fleet fueling, and farm tanks over applicable thresholds register with DHEC.

CAFO Animal-Waste Storage Deep Dive — R.61-43

R.61-43 is the regulation that matters most to South Carolina tank buyers in the hog and poultry belts. Key design and operating requirements for permitted animal-waste storage structures:

• Engineered design — waste lagoons and above-ground storage tanks require signed and sealed professional-engineer design with specified side slopes, liner permeability (typically ≤ 1 x 10^-7 cm/sec for earthen lagoons), and hydraulic storage volume meeting 180-day minimum for swine and per-species requirements for poultry mortality and litter management.
• Freeboard & monitoring — minimum operating freeboard (commonly 1 ft for lagoons), monthly level recording, and emergency freeboard thresholds that trigger land-application or pumping-down actions.
• Certified Animal Waste Manager — every permitted facility must have a CAWM on staff with DHEC-issued certification; Clemson Extension administers training.
• Nutrient Management Plan — NRCS Code 590-aligned NMP governs land application rates, setbacks from surface waters (typically 100 ft), wells (100 ft), and occupied dwellings.
• Annual reports & sludge surveys — permittees file annual compliance reports; lagoon sludge surveys at specified intervals determine sludge-removal scheduling.

Poly and steel above-ground animal-waste storage tanks (for slurry transfer, land-application staging, or composting leachate capture) must meet the same containment, setback, and permit requirements as lagoons if their capacity exceeds threshold. DHEC enforcement under R.61-43 is active in the Pee Dee swine belt and Upstate broiler belt; operators coordinate with DHEC regional offices for pre-construction plan approval.

OWTS Septic System Sizing — R.61-56

DHEC regulates on-site wastewater treatment systems (OWTS) under R.61-56 Onsite Wastewater Systems. Residential design flow is 120 gpd per bedroom:

South Carolina soils run from Blue Ridge rocky residual in the Upstate, Piedmont red-clay B-horizons (tight, slow perc), Sandhills deep sands (fast perc, groundwater protection concerns), Coastal Plain sandy loams, and Lowcountry tidal marsh and high-water-table soils where conventional drainfields frequently fail. DHEC Environmental Affairs field staff conduct site evaluations; licensed master-septic installers construct. Alternative systems common in SC: aerobic treatment units (ATU) with drip dispersal in Lowcountry high-water-table sites, mound systems in shallow-bedrock Upstate lots, low-pressure pipe (LPP) systems, and advanced pretreatment packages for shellfish-growing-water-basin adjacency. Coastal counties require elevated tanks and anti-flotation ballast in flood-prone zones.

Chemical Storage Secondary Containment & Spill Reporting

Federal SPCC (40 CFR 112) applies at 1,320 gallons aggregate aboveground oil. South Carolina layers on:

• R.61-68 Water Classifications and Standards — state water quality standards that frame discharge-related enforcement.
• R.61-79 (RCRA) — hazardous waste generator requirements, accumulation limits, and container management.
• DHEC 24-hour Emergency Response Line — 888-481-0125 for release notification.
• SC Emergency Response Commission / LEPC — EPCRA Tier II filings through SC Emergency Management Division.

Report federal-RQ releases to the National Response Center at 1-800-424-8802; report state releases to DHEC's 24-hour emergency line. Secondary containment at 110% of the largest tank is the SPCC and industry default; R.61-43 animal-waste structures have their own engineered liner and freeboard requirements. For state-specific RQ thresholds consult DHEC Emergency Services Program.

Permit Pathways at a Glance

• Residential OWTS: DHEC Environmental Affairs under R.61-56.
• Fertilizer registration & tonnage: Clemson University / SCDA under SC Code Title 46.
• Pesticide applicator license: SCDA under R.27-1060.
• Animal-waste storage (CAFO): DHEC under R.61-43.
• Petroleum UST: DHEC UST Program under R.61-92 with SUPERB Fund participation.
• SPCC > 1,320 gal oil aggregate: Federal SPCC plan; DHEC state spill reporting.
• NPDES industrial stormwater: DHEC (SC is delegated NPDES state) under R.61-9.
• Hazardous waste: DHEC under R.61-79 (RCRA delegation).

Current fees change; verify with DHEC, SCDA, or Clemson Regulatory Services before budgeting.

More South Carolina FAQs

What is the SUPERB Fund and does it pay for my cleanup?

The State Underground Petroleum Environmental Response Bank (SUPERB) is a state trust fund, financed by UST registration fees, that reimburses eligible corrective-action costs for registered tanks in good standing. Eligibility, cap amounts, and deductibles are set by DHEC; confirm current parameters with the DHEC UST Management Division before relying on fund coverage in your budget.

Do I need a permit for a chicken-house manure shed?

If the operation exceeds the R.61-43 animal-unit thresholds (which vary by species — broilers, layers, turkeys, and swine each have specific counts), yes — the facility needs a DHEC agricultural animal-facility permit with engineered waste-storage design, setback compliance, nutrient management plan, and a Certified Animal Waste Manager. Small flocks below threshold are not regulated under R.61-43 but still face local zoning, county health, and NPDES stormwater rules if applicable.

What is the difference between DHEC Environmental Affairs and SCDHEC Public Health?

As of 2024 South Carolina reorganized DHEC into two separate agencies: the SC Department of Environmental Services (DES) handles environmental programs including UST, hazardous waste, water quality, and CAFO; the SC Department of Public Health handles health programs including OWTS permitting. Regulatory citations still reference “DHEC” in pre-reorganization rules; operators should confirm current administering agency for each program because the reorganization is ongoing.

Does SC have its own AST rule beyond SPCC?

SC does not operate a comprehensive state AST registration program comparable to Texas 30 TAC 334 Subch. I or West Virginia 47 CSR 63. Petroleum AST operators follow federal SPCC when over threshold; state oversight comes through R.61-9 water pollution, R.61-79 hazardous waste, and DHEC release reporting. If facility operations trigger hazardous-waste status, R.61-79 generator rules apply.

Who handles shellfish-growing-water setbacks?

DHEC Bureau of Water administers SC's shellfish-growing-water classification program in coordination with coastal counties. Proximity to approved or conditionally approved shellfish-growing waters (Lowcountry creeks and estuaries) tightens OWTS siting, tank setbacks, and animal-waste land-application buffers. Site evaluation during septic permitting is the first step to identify shellfish-waters proximity.

What does Clemson Regulatory Services do?

Clemson University's Department of Pesticide Regulation and the Fertilizer/Lime programs administer portions of SC agricultural regulation under delegation from SCDA. Applicator certification, product registration, tonnage reporting, and inspection functions commonly route through Clemson. Coordinate with Clemson Regulatory Services for pesticide and fertilizer compliance alongside any DHEC environmental permitting.