Horry County Septic Permits: Groundwater, Flooding, and Repair Grants

Sourced from R.61-56 (amended May 23, 2025), the Horry County Land Development Regulations, the Grand Strand Water and Sewer Authority 2040 Plan, the SC Nonpoint Source Management Program 2024 Annual Report, the Horry County Flood Resilience Master Plan, and US Census population estimates — last checked August 2026.

Who Issues Horry County Septic Permits

This is the part that surprises people moving to South Carolina from almost anywhere else: Horry 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.

Someone Else May Pay for Your Septic Repair

This is the most valuable thing on this page and almost nobody in Horry County knows about it.

Since 2011, the Horry Soil and Water Conservation District has completed 908 septic repairs and 282 sewer tie-ons — along with 38 agricultural projects, for 1,190 projects across 26 subwatersheds. The work is funded by Clean Water Act Section 319 grants, with matching money from Grand Strand Water & Sewer, the City of Conway, Horry County Stormwater and the NRCS.

It is still running. A Phase II project beginning in 2025 targets 43 households along with 40 cattle and 15 horses. South Carolina’s conservation district reporting recorded 78 installations of sewer tie-ons and septic tank and field lines in FY2025 alone.

The catch is geography: eligibility runs by subwatershed, not by county. So the question to ask is not “is there a program” but “is my address in a targeted subwatershed this cycle.” Contact the Horry Soil and Water Conservation District and ask directly. If you have a failing system and limited means, this is the first call to make, before you call an installer.

There is precedent for the county going further. Bucksport and Longs were once designated imminent health hazard areas; GSWSA spent over $6,000,000 in 1986 connecting more than 500 households within 24 months, using a construction grant, Farmers Home Administration money and CDBG funds. Since 1992 its rural program has served well over 1,500 households.

Growth Is the Context for Everything Else

Horry County is one of the fastest-growing counties in the United States:

• 2020 Census: 351,029
• July 1, 2025 estimate: 427,551 — a 21.8 percent increase in five years
• Between July 2023 and July 2024 it was the 34th fastest-growing county in the country
• Its 2010–2020 gain of 30 percent was the largest of any county in either Carolina
• GSWSA projects 584,000 by 2040

Statewide, septic applications went from about 8,000 in 2010 to more than 16,000 in 2022, and the eight coastal counties took over 10,900 applications between 2021 and 2023 — almost all approved, with record highs five years running. There is no public notice requirement for a septic permit and only a 15-day window in which one can be challenged.

Flooding: What the Permit Does Not Consider

That matters more in Horry than almost anywhere, because Horry floods and because FEMA’s maps understate where. From the county’s own Flood Resilience Master Plan: Hurricane Florence in September 2018 damaged more than 2,000 buildings and closed more than 460 roads, with South Carolina damages totalling $2 billion. Socastee has the highest number of repetitive-loss properties in the county.

And the finding that should change how you read a flood map here: fewer than 20 percent of the buildings damaged by flooding during Florence — 96 of 565 — were inside the effective FEMA flood hazard area. Being outside the mapped zone is not evidence your lot stays dry.

Mounded and engineered systems are available under R.61-56 Appendix N (Standard 420/421) and Appendix O (Standard 431), and a licensed South Carolina engineer may design a Standard 610 system for flows under 1,500 gpd. Horry County does not mandate any of them — they are options you or your soil classifier may choose.

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 Horry County is where the rule draws the most criticism. A local installer of thirty years, Roger Herrington, told the Post and Courier: “They’re putting septic tanks in the wettest areas I’ve ever seen.” Coastal geologist Rob Young of Western Carolina University put the consequence bluntly in the same reporting: “98 percent of the failures in the coastal zone… you’re not going to see,” and “You can’t deal with this a parcel at a time.”

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. In Horry that reserve area competes with a high water table, so the honest question to ask a soil classifier is not just whether the lot passes today, but whether the reserve area would still pass in a wet season.

Setbacks and Sizing in Horry 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. Horry County adds one platting rule rather than a lot-size minimum: under the Land Development Regulations (adopted November 20, 2001), Article 2 § 3-4(A), creating a parcel under five acres requires either written approval that it can be served by water, sewer or an onsite system, or a signed “Certificate of Non-Evaluation.” That certificate is worth understanding before you sign one — it means nobody has checked whether the lot will take a system. A smaller quirk from the same regulations (§ 3-10): a shared private driveway easement must be 30 feet wide if the parcels are on septic, 50 feet if on public water and sewer.

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 Grand Strand Water and Sewer Authority is the dominant provider, and its retail territory is any part of Horry County not assigned to another utility. Its growth is the story: sewer customers went from 70,339 in 2014 to 120,515 in 2024, across 2,313 miles of mains and 16 treatment plants, reaching 141,938 total accounts in FY2025. But the county’s own Stormwater Management Plan says plainly that “the rural areas depend largely on onsite wastewater treatment systems.” West of the Waccamaw River, outside Conway and Loris, there was almost no public wastewater at all before 1986. We could not find any Horry County ordinance setting a mandatory sewer-connection distance, so the state’s accessibility test is what governs.

What We Could Not Confirm

Where Horry County Sits

Myrtle Beach, Conway and North Myrtle Beach anchor a county absorbing tens of thousands of new residents while its rural west remains largely on onsite systems, on soil that holds water for weeks after a storm. The combination — the nation’s loosest groundwater separation standard, the fastest growth in the Carolinas, and repeated flooding outside the mapped flood zones — is what makes Horry the most consequential septic county in South Carolina.

Nearby counties we cover: Marion 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.