Berkeley County, SC Stormwater Regulations

Berkeley County is a co-permittee on the Charleston metro Phase II Small MS4 NPDES permit, managed through coordination with SCDES. The county enforces stormwater controls on construction and post-construction activities, with state penalties up to $10,000 per day. Rapid growth in the Moncks Corner and Goose Creek areas drives active enforcement.

Primary source: South Carolina Department of Environmental Services (SCDES)

Permit Requirements

Berkeley County requires NPDES Construction General Permit coverage for any land-disturbing activity of one acre or more. The permit (SCR100000) is issued by SCDES and requires a Stormwater Pollution Prevention Plan (SWPPP) that details erosion and sediment control measures during construction and permanent post-construction BMPs.

As a Charleston metro MS4 co-permittee, Berkeley County must ensure that post-construction stormwater management meets the performance standards outlined in the MS4 permit. New development and redevelopment projects must incorporate permanent stormwater controls designed to manage both water quality and peak flow rates.

Berkeley County's growth, particularly along the US-17A and I-26 corridors near Goose Creek and Moncks Corner, has increased the volume of stormwater permit applications. The county's planning and zoning department reviews stormwater management plans as part of the development approval process.

Inspection Obligations

Construction sites under NPDES permit coverage must be inspected at least once every seven calendar days and within 24 hours of any rainfall event of 0.5 inches or greater. Inspections must be conducted by a qualified inspector and documented using SCDES-approved forms.

Post-construction BMPs require annual inspections by the responsible party, typically the property owner or HOA. Berkeley County tracks permitted stormwater facilities and may conduct its own inspections to verify compliance. Inspection reports must document the condition of all structural components, sediment accumulation levels, vegetation health, and outlet structure functionality.

The county's MS4 program also includes dry-weather screening of outfalls to detect illicit discharges. County inspectors check for unauthorized connections to the storm sewer system, including wash water, process wastewater, and sanitary sewer overflows.

Penalty Structure

SCDES enforces state stormwater violations under the SC Pollution Control Act (SC Code Section 48-1-330), with civil penalties up to $10,000 per day per violation. Common violations include operating without a permit, failing to implement SWPPP measures, and discharging sediment-laden water to state waters.

Berkeley County's local enforcement includes notices of violation, compliance orders, and fines for violations of the county's stormwater management ordinance. The county can also pursue injunctive relief through the courts and recover costs for emergency maintenance performed on private facilities.

Enforcement actions are often triggered by citizen complaints, routine county inspections, or observations during construction site reviews. Properties with repeated violations may face escalated enforcement, including referral to SCDES for state-level action.

Key BMPs

Berkeley County's topography and soil conditions influence BMP selection. The county encompasses both coastal lowlands near the Cooper River and upland areas toward the Francis Marion National Forest. Common approved BMPs include:

• Wet detention ponds - The most widely used BMP in Berkeley County developments. Sized to capture and treat the first inch of runoff from impervious surfaces.
• Dry detention basins - Used where permanent pools are not feasible. Must drain within 24-72 hours and provide peak flow attenuation.
• Bioretention cells - Effective for smaller commercial and residential sites. Engineered soil media filters stormwater before it enters the drainage system.
• Vegetated buffers - Required along streams and waterways. Berkeley County's riparian buffer requirements help protect water quality in tributaries of the Cooper and Santee rivers.
• Underground detention - Used in commercial areas where surface space is limited. Must include maintenance access and sediment removal capability.

Local Ordinances

Berkeley County's stormwater management ordinance requires all new development to manage post-construction stormwater runoff. The ordinance works in coordination with the county's MS4 permit obligations and covers illicit discharge detection, construction site runoff control, and post-construction stormwater management.

The county requires maintenance agreements for all permanent stormwater BMPs. These agreements run with the land and transfer to subsequent property owners, including HOAs that take over maintenance responsibility from developers. The agreement specifies inspection frequency, maintenance responsibilities, and the county's right to access and inspect facilities.

Berkeley County also enforces floodplain management regulations through its participation in the National Flood Insurance Program. Development within FEMA-designated flood zones requires additional stormwater management considerations and may trigger compensatory storage requirements.