Sourced from Dorchester County Zoning and Land Development Ordinance 04-13, Dorchester County Water and Sewer, and R.61-56 — last checked August 2026.
Who Issues Dorchester County Septic Permits
This is the part that surprises people moving to South Carolina from almost anywhere else: Dorchester 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.
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Septic Is Banned in Major Subdivisions
This is the strictest subdivision rule we have found in South Carolina, and it is the first thing to establish about any Dorchester property.
The exemption: “Major and minor subdivisions where the resulting lots will be five acres or greater are exempt from the requirement to connect to public sewer.”
So the practical geometry of Dorchester County is this: if you are inside a major subdivision under five acres, sewer is not a choice, it is the requirement. Above five acres, or in a minor subdivision, septic is available.
A seller-side duty that catches people
For minor subdivisions under five acres without public sewer, § 20.12 puts the obligation on the seller: the “seller must obtain soil analysis for on-site wastewater disposal before property is subdivided, developed or sold,” and every lot must be shown to support both a tank and a drainfield.
That is unusual and worth acting on. If you are selling raw land in Dorchester County, the soil work is yours to commission, not the buyer’s. If you are buying, ask for it — and treat its absence as a question rather than an oversight.
Section 20.12 also requires compliance with the separate Dorchester County Sewer Use Ordinance No. 84-23.
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 Dorchester sits partly in the Lowcountry, so a soil evaluation done in a dry month can flatter a lot that behaves differently in February.
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. With a one-acre minimum in the AR district and the state reserve requirement on top, an older Dorchester lot platted before those rules may be tighter than it looks.
Setbacks and Sizing in Dorchester 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. Dorchester supplies its own minimums where the state does not: AR district 43,560 square feet (one acre) per § 9.1.6(a), with each dwelling requiring its own system or sewer connection; RX district one acre minimum per § 9.3.5(a), lots to be “of sufficient size to meet the minimum requirements” of the state; and the CV district ranging from half an acre to ten acres.
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.
Three providers serve the county: Dorchester County Water & Sewer, the Town of Harleyville, and Summerville Commissioners of Public Works. DCWS is substantial — roughly 25,000 sewer customers across about 263 square miles, with 126 pump stations, some 315 miles of gravity sewer and about 115 miles of force main, and a further 4,000 customers billed on its behalf by Charleston Water System. Capacity is being pushed hard: the June 2026 state Clean Water revolving fund priority list includes a Lower Dorchester plant expansion to 16 MGD ($4,442,000 for planning and design), a $30,000,000 new 43,000-foot force main for Pump Station 72, and a $45,000,000 Middleton land conservation project. DCWS also charges a non-refundable origination fee of $25 residential, $100 commercial — published without an effective date, so confirm it.
What We Could Not Confirm
Adoption and amendment dates. We have the ordinance numbers — 04-13 for the zoning and land development ordinance, 84-23 for the sewer use ordinance — but no adoption or amendment dates beyond those numbers. Given the sewer ordinance number suggests 1984, confirm the current version before relying on it.
A sign the code is only half-updated: Article IX still refers to the “SC Department of Health and Environmental Control” while § 20.12 says SCDES. Both are in the same instrument. That is a hint that other parts may be dated too.
Any Dorchester-specific high water table requirement. We found none — the state rules govern. That is an absence of evidence rather than proof of absence, and on a Lowcountry lot it is worth asking about directly.
Where Dorchester County Sits
Summerville and St. George anchor a county split between the Charleston metro edge and rural farmland, with sewer capacity being expanded under real pressure. What sets Dorchester apart is that it has decided the question for you in most subdivisions — the five-acre line, not the soil report, is what determines whether septic is even on the table.
Nearby counties we cover: Charleston County · Berkeley County · Colleton 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.
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