Understanding the MS4 Area in Berkeley County, South Carolina — Rules, Impacts & What Landowners Should Know

The term MS4 (Municipal Separate Storm Sewer System) may sound technical, but it has real implications for property owners, developers, planners, and local government in Berkeley County, South Carolina. In this post, we’ll demystify what the MS4 area means in Berkeley County, walk through key regulatory requirements, and explore how compliance affects land development and management.

What is an MS4?

An MS4 is a network of stormwater conveyances — such as catch basins, curbs, gutters, ditches, man-made channels, pipes, and tunnels — that collect and channel stormwater runoff and discharge it into Waters of the State, separate from sanitary sewer systems.

In South Carolina, operators of regulated MS4s must secure NPDES permit coverage and meet a set of obligations designed to reduce pollutant discharges and protect water quality.

Berkeley County is classified as a Phase II MS4 jurisdiction, meaning it must meet minimum control measure requirements, monitor discharges, adopt infrastructure standards, and enforce compliance within its regulated area.

The Berkeley County MS4 Program: Structure & Goals

Berkeley County’s MS4 / Stormwater Management Program (SWMP) is built around the federally mandated “minimum control measures” (MCMs).

Here’s a breakdown of key program components:

Component	Description / Requirements	Notes for Landowners / Developers
Public Education & Outreach	Inform citizens, contractors, developers about stormwater impacts, good practices	Developers often must supply erosion control plans, BMP (best management practices) documentation
Public Participation / Involvement	Gather public feedback, provide forums, publish reports	Opportunity for community input in plan updates
Illicit Discharge Detection & Elimination	Identify and eliminate non-stormwater discharges (e.g. sewer leaks, washwater, oils)	Landowners must avoid prohibited discharges; complaints are accepted via Berkeley County’s illicit discharge reporting program
Construction Stormwater Runoff Control	Enforce sediment and erosion control on construction sites	Developers must submit erosion & sediment control plans; inspections occur during construction
Post-Construction Stormwater Management	Ensure long-term BMPs, retention, detention, vegetation, infiltration	New development must meet county design standards (see Design Standards Manual)
Pollution Prevention / Good Housekeeping	Address municipal operations, maintenance, planning	County inspects its own facilities; contractors must follow proper chemical, waste, vehicle practices

Additionally, Berkeley County has adopted a Stormwater Design Standards Manual (adopted December 1, 2009) that provides technical guidelines on how to design drainage, erosion control, BMPs, and site layout to comply with permit requirements.

To fund program implementation, the county collects a Stormwater Utility Fee from developed properties (residential, commercial, nonprofit) based on impervious surface.

Importantly, properties that remain undeveloped, or those classified as agricultural / forestland, are generally exempt from the fee.

Regulatory Impacts on Land Use, Development & Ownership

For real estate developers, landowners, or investors in Berkeley County (or jurisdictions under its intergovernmental agreements such as Goose Creek or Hanahan), MS4 regulations impose several considerations:

1. Upfront Planning & Compliance
   • Any new site plan or major renovation must account for stormwater management (erosion control, post-construction BMPs). Failure to comply can lead to stop-work orders, permit denials, or fines under the illicit discharge protocols.
2. Added Costs
   • Incorporating stormwater infrastructure (detention ponds, vegetated swales, infiltration systems) raises site design costs. The impervious-area–based utility fee further increases ongoing costs for developed parcels.
3. Design Constraints & Density
   • Because regulations push toward minimizing impervious surfaces, using pervious pavements or preserving natural drainage, site layouts may change (less parking, more green buffers).
4. Long-Term Maintenance & Liability
   • BMPs required under post-construction maintenance must be maintained in perpetuity, and failure to do so can trigger penalties or corrections by the county.
5. Permitting Coordination & Timeline Impacts
   • The development review process includes stormwater engineering review, plan checks, revisions, and interdepartmental coordination. As described by Berkeley County’s Development Review Services, plans go through a coordinated review with engineering, planning, and zoning.
6. Appeals & Credits
   • Property owners can apply for credits or appeal the stormwater utility fee within a limited timeframe.

Thus, for someone considering buying or developing vacant land in Berkeley County, understanding whether the site lies within a regulated MS4 area is essential.

How to Determine MS4 Areas in Berkeley County

• Berkeley County (and its partner municipalities) maintain mapping of the MS4 service area.
• The South Carolina Department of Health & Environmental Control provides MS4 designations and mapping tools.
• When submitting plans, county staff will determine whether a parcel is under MS4 jurisdiction, and require applicable stormwater submittals during review.
• If in Moncks Corner (within Berkeley County), the town itself enforces its own stormwater permitting program under South Carolina Regulation 72-300 starting June 1, 2021.

Best Practices & Tips for Landowners / Developers

• Early coordination with county stormwater engineering is critical — don’t wait until final plan to figure out drainage design.
• Integrate low-impact development (LID) techniques: rain gardens, permeable pavements, green roofs, bioswales, natural buffer zones.
• Keep impervious coverage as low as feasible, cluster development, preserve natural features.
• Ensure you have long-term maintenance plans for your BMPs, and document them in required maintenance covenants.
• Monitor and inspect during construction to prevent sediment runoff and illicit discharges.
• Stay current on annual reporting requirements, public outreach obligations, and regulatory updates from the county or South Carolina regulatory bodies.

The MS4 program in Berkeley County, South Carolina is more than just a regulatory box to check — it’s a framework that shapes how land is developed, demands higher-quality stormwater design, and ensures that growth and water quality protection go hand in hand. For real estate investors, developers, and landowners, understanding MS4 boundaries, design obligations, ongoing maintenance, and stormwater costs is essential.