Richland County, SC Stormwater Regulations

Richland County runs a Phase I medium MS4 program under NPDES permit SCS400001, covering the unincorporated county plus Arcadia Lakes and Forest Acres. The City of Columbia runs its own separate program and utility fee. County rules sit in Sec. 26-5.11 of the Land Development Code: any land disturbance needs a county permit, private ponds are inspected every year, and civil penalties run up to $500 per violation per day.

Primary source: Richland County Stormwater Management Division

Permit Requirements

Richland County's threshold is lower than the state's. Under Sec. 26-2.5(l) of the Richland County Land Development Code, a county land disturbance permit is required before any grading, construction, or land disturbance of any nature. The listed exemptions are agricultural production and forestry.

Every permit comes with an approved Stormwater Pollution Prevention Plan (SWPPP). A Level I SWPPP covers land disturbance totaling less than one acre that isn't part of a larger common plan of development or sale. A Level II SWPPP is required at one acre or more. At that size the project also needs coverage under the SCDES NPDES Construction General Permit (SCR100000), and the county issues its land disturbance permit after the state coverage decision.

Who reviews your plans depends on where the site is. The county's program covers the unincorporated county and its MS4 co-permittees, the Town of Arcadia Lakes and the City of Forest Acres. The City of Columbia is a separate medium MS4 with its own permit and its own code, so a site inside city limits goes through the city. The county's manual also notes intergovernmental agreements with Blythewood and Irmo, so confirm the reviewing office before you design for a site in either town.

Inspection Obligations

The county's Private Pond Inspection Program inspects each privately owned pond in its MS4 area once a year. If a pond doesn't meet the county code, the owner gets a Notice of Violation with instructions for getting back into compliance.

Maintenance is the owner's job. Sec. 26-5.11 says all stormwater management facilities must be maintained by their owners, at the owner's sole cost when the facility is private. The county only takes on maintenance where it holds an access easement and has formally accepted the responsibility. Owners also have to give the county engineer certified as-built plans and periodic maintenance reports when asked. The county's pond checklist calls for monthly mowing, quarterly structure inspections plus one after any storm of 2 inches in 24 hours, and sediment removal once 12 inches builds up.

During construction, the Land Development Manual requires third-party inspections every 7 calendar days and within 24 hours after each rainfall of 0.5 inches or more. Reports go in the on-site construction box within 72 hours. County inspectors run their own compliance inspections on top of that and check that the third-party reports are happening and accurate.

Penalty Structure

County penalties are small per violation, but they stack daily. Sec. 26-5.11 sets a civil penalty of not more than $500 for each violation, and each separate day is a new violation. Anyone who negligently, willfully, or intentionally violates the article can also be charged with a misdemeanor in magistrate's court, with each day a separate offense.

Enforcement usually starts with a notice of violation and a deadline to cure. The owner can ask in writing for one extension of up to 30 days. After that, Article 26-8 lets the county withhold pending or later permits, issue a stop work order, revoke a permit, or go to court for an injunction. Letting a stormwater facility deteriorate to the point that it endangers health, safety, and welfare is itself a violation. If a discharge poses an imminent threat, the county can step in and then seek its cleanup costs back from the responsible party.

State penalties sit above the county's. SCDES can assess civil penalties up to $1,000 per day under the Stormwater Management and Sediment Reduction Act (SC Code Section 48-14-140) and up to $10,000 per day under the South Carolina Pollution Control Act (SC Code Section 48-1-330).

Key BMPs

The county's 2024 Land Development Manual sets two water quality design standards and lists the BMPs it accepts. New permanent BMPs must either infiltrate the runoff from the Water Quality Storm Event (the 1.4-inch, 24-hour storm) within 72 hours or remove 85 percent of total suspended solids on an annual basis. Post-development peak discharge can't exceed pre-development rates for the 2-, 10-, and 25-year, 24-hour storms. The manual's standard application BMPs include:

• Wet detention ponds - Listed along with wet modified extended detention ponds. Privately owned ponds in the county's MS4 area fall under the annual Private Pond Inspection Program.
• Dry extended detention ponds - A standard application BMP. The county's pond checklist covers outlet structures, orifices, and outlet pipes, which need to be kept clean and unclogged.
• Infiltration trenches and dry wells - Infiltration practices line up with the county's first design standard, which the manual says is typically most feasible in sandy soils with higher infiltration rates.
• Bioretention - A standard application BMP. The county requires a signed maintenance agreement for every permanent structural BMP.
• Vegetated filter strips - Also on the standard list. Grass swales, enhanced swales, and porous pavement are on the manual's limited application list.

Local Ordinances

Richland County's stormwater rules live in Chapter 26 of the county code, the Land Development Code, which was revised November 14, 2023 and took effect March 1, 2024. Sec. 26-5.11 (Water Quality) holds the water quality buffers, stormwater management standards, maintenance duties, and the county's NPDES MS4 program. That program makes illicit connections, illicit discharges, improper disposal, and illegal dumping into the storm system unlawful. The County Engineer enforces it.

Water quality buffers are a big part of the local rules. The code requires at least 50 feet on each side of jurisdictional perennial and intermittent streams, 50 feet beyond wetland edges, and 50 feet on connected pond and lake shorelines. The width goes to 100 feet where the stream is on the 303(d) list or has an approved TMDL. Single-family lots of two acres or less that aren't part of a new subdivision are exempt.

The county doesn't send a stormwater utility bill. It pays for the program with a property tax levy, which the 2025 millage schedule lists at 3.2 mills in the Arcadia Lakes and Forest Acres districts and the county's non-municipal tax districts. Inside Columbia, Columbia Water bills a stormwater utility fee of $15.03 per month for a single-family home. Other properties pay per Equivalent Residential Unit of 2,454 square feet of impervious area.

Richland County is inland, so the OCRM coastal zone rules that apply in South Carolina's eight coastal counties don't apply here. Report suspected illicit discharges to the county's stormwater hotline through the Ombudsman at 803-929-6000.