Marion County Septic Permits: A Real Lot-Size Floor

Sourced from the Marion County Zoning Ordinance, the City of Marion Zoning Ordinance #06-13, the Grand Strand Water and Sewer Authority 2040 Plan, US Census counts, and R.61-56 — last checked August 2026.

Who Issues Marion County Septic Permits

This is the part that surprises people moving to South Carolina from almost anywhere else: Marion County does not issue septic permits, and neither does any other South Carolina county. Onsite wastewater permitting is a state function.

The agency is the South Carolina Department of Environmental Services (SCDES), created on July 1, 2024 when Act 60 of 2023 split the old DHEC into SCDES for environmental programs and SC DPH for public health. Septic sits in SCDES’s Bureau of Regional and Laboratory Services.

Where the application goes: ATTN: OSWW, SCDES, 2600 Bull Street, Columbia, SC 29201
Statewide phone: 1-855-731-2504 (Onsite Wastewater Customer Service Center)
Online: epermitting.des.sc.gov
Form: D-1740, revision 07/2026

The Fee Is the Same in Every County: $150

Because permitting is centralized, there is one fee statewide. R.61-56 § 102.2: the Department “shall charge a fee of one hundred and fifty dollars ($150.00) to evaluate the site of a proposed onsite wastewater system.” That section was amended effective May 27, 2022. Payment is by check or money order to SCDES, and there is a $150 re-application fee if the application instructions are not followed.

There is a second route worth knowing about. You may hire a Professional Soil Classifier to do the evaluation privately, and the rules cap what they may charge at “no more than three (3) times SCDES’s fee” — so up to $450 (form DES 25-0011, dated 07/2025). People use it to skip the queue, and the queue is real: SCDES reported a 700-permit backlog in April 2023, and coastal counties have run six to fourteen weeks behind.

Well Setbacks You Would Not Expect to Find in a Zoning Code

Two provisions in the Marion County Zoning Ordinance protect drinking water at distances far beyond anything in the septic rules, and they are worth knowing if you are on a well:

• § 5-4(1)(b): sanitary landfills must be at least 5,000 feet from any potable well.
• § 5-5(1)(b): hazardous waste facilities must be at least 7,500 feet from any potable well.

For comparison, your septic drainfield must be 75 feet from your well under state rules. The county evidently takes a different view of risk depending on the source.

The county’s planned development provisions also require applicants to map FEMA flood plains and jurisdictional wetlands (§ 3-7.7(1)(n)), and § 4-2.4 requires an Army Corps wetlands determination. Note that the City of Marion’s own zoning ordinance, #06-13, contains no septic or sewer provisions at all — its Article IX is flood hazard standards.

Nichols: What Repeated Flooding Actually Does

Marion County contains the clearest illustration in South Carolina of what happens when water keeps coming.

After Hurricane Matthew in October 2016, five months on, 216 of the town of Nichols’ 261 homes remained vacant. Two of six churches were still closed, as were 15 of 22 businesses, the library, and most fire and police resources. The mayor requested $700,000 to repair nearly 400 water-damaged buildings, replace vehicles and reopen government offices.

The county’s population has fallen every decade: 35,466 in 2000, 33,062 in 2010, 29,183 in 2020. For a septic page that matters in a specific way — a shrinking ratepayer base makes sewer extension into unsewered areas less likely, not more. In Marion County, repair and maintain is the realistic path rather than waiting for a connection.

And the Rule That Does Not Consider Any of This

The Rule That Costs the Most Money: Six Inches

South Carolina requires a minimum vertical separation of six inches between the deepest point of effluent application and the zone of saturation — the level groundwater reaches — for systems under 1,500 gallons per day (R.61-56 § 200.3).

Six inches is remarkably little, and the comparison is the fastest way to understand it:

• South Carolina — 6 inches
• North Carolina — 18 inches on the coast, 12 inches inland
• Georgia — 24 inches
• Alabama — 24 inches

South Carolina permits systems on ground its neighbors would refuse. That is legal, and it is also why Marion sits in the Pee Dee flood plain and has been inundated repeatedly, so the wet-season water table is the number that matters here rather than a dry-month reading.

The Repair Area Nobody Tells You About

Under R.61-56 § 200.7, a new system must reserve “a usable repair or replacement area equivalent to at least fifty (50) percent of the size of the original system” — 100 percent for community systems.

Read that as a land requirement, because that is what it is. Your lot has to hold the tank, the drainfield, and half a drainfield again in reserve, while still meeting every setback. On a tight lot that reserve area is what fails, not the drainfield itself. On a 10,000 square foot Marion lot the reserve area is a genuine constraint, not a formality.

Setbacks and Sizing in Marion County

These come from R.61-56 and apply identically statewide:

• 75 feet from a private well · 100 feet from a public well
• 75 feet from the mean high water line of a stream, canal or retention pond, and from a delineated critical area line (tidal waters and tidelands)
• 25 feet from a drainage ditch · 25 feet upslope of a basement
• 5 feet from a property line · 5 feet from a building
• Rock or a restrictive horizon must sit more than 12 inches below the deepest point of effluent application

There is no state minimum lot size for a septic lot. R.61-56 requires only that the lot be large enough to hold the system, the reserve area and the setbacks. Marion County Zoning Ordinance § 4-10.2 requires that buildings not on a public sewer system meet the state’s area requirements “but in no case shall the requirements be less than the following”: single-family detached dwelling 10,000 square feet; mobile home on an individual lot 10,000 square feet; duplex 18,000 square feet. Since the state sets no minimum, this is a genuine local floor. The latest amendment we could see in that ordinance dates to September 25, 2008 — confirm the figures are current before you rely on them.

When Sewer Blocks a Septic Permit

R.61-56 § 300 is blunt: “Permits for new onsite wastewater systems shall not be issued where a wastewater treatment facility is accessible for connection,” and the same bar applies to repairing or replacing a failing system.

But the state sets no distance. “Accessible” is defined only negatively — “where annexation or easements to cross adjacent property are required to connect… the wastewater treatment facility shall not be considered accessible.” So if connecting would require you to be annexed, or to cross a neighbor’s land, sewer is not accessible and your septic permit stands.

The designated wastewater agencies are the City of Marion, Mullins, Nichols and the county itself for unincorporated areas. One unusual arrangement worth knowing: the Grand Strand Water and Sewer Authority — the Horry County utility — provides sewer service to the Centenary community inside Marion County. We found no documented sewer expansion project for Marion County with dates or figures.

Where Marion County Sits

Marion, Mullins and Nichols sit in the Pee Dee, on flat ground drained by rivers that have flooded catastrophically twice in recent memory. It is a shrinking county with real local lot-size rules, very little sewer, and a permitting standard that does not look at flood risk — which puts more weight than usual on getting the soil evaluation right.

Nearby counties we cover: Horry County · Dillon County. All of them run through the same state permit and the same $150 fee — what differs is the local ordinance layer, which is compared on our South Carolina septic permits by county page.