Charleston, SC Environmental Rules: Stormwater Management (2026)
Key Facts
- Core standard section
- City Code § 27-29(a)
- Impervious cover reduction option
- At least 20 percent cut required
- Runoff volume option
- 10 percent cut, two-year storm event
- Enforcing department
- City Department of Stormwater Management
- Appeal body
- Public works and utilities committee, 30 days
- Maintenance duty
- Property owner maintains on-site drainage facilities
Summary
Charleston regulates stormwater runoff citywide under Chapter 27's Stormwater Management Ordinance, requiring qualifying redevelopment projects to cut runoff before it leaves the site. City Code § 27-29(a) makes qualifying redevelopment choose one of three numeric performance standards, such as cutting impervious cover by at least 20 percent, and the department of stormwater management reviews and approves the chosen approach before work begins.
(a)Other than projects with parcel areas less than one (1) acre or where more than eighty (80) percent of the existing building footprint shall remain undisturbed, one (1) of the following performance standards shall be implemented for the entire parcel in question as approved by the department of development services:(1)Reduce the impervious cover on the site by at least twenty (20) percent, based on a comparison of existing impervious cover at the time of submittal of a construction activity application; or
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 114 | Zoning: Supplement 25).
Full Breakdown
Article I of Chapter 27 is the city's Stormwater Management Ordinance, adopted because Charleston must hold a federal NPDES permit from the South Carolina Department of Health and Environmental Control for its stormwater system, per § 27-3(c). The ordinance's core numeric standard sits in § 27-29(a): redevelopment projects covering a parcel of one acre or more, where more than 20 percent of the existing building footprint will be disturbed, must meet one of three performance standards approved by the department of stormwater management. A project can reduce impervious cover on the site by at least 20 percent compared to existing conditions, cut the 24-hour runoff volume from a two-year storm by 10 percent while keeping the post-development peak discharge at or below the pre-development rate, or reduce post-development peak discharge rates by 10 percent for the 10-year and 25-year, 24-hour storm events.
§ 27-32 separately requires anyone owning property along a watercourse to keep that stretch free of trash and debris that would block or pollute the flow. Appeals from a denied application go to the public works and utilities committee under § 27-69, within 30 days of the decision.
Violations & Fines
A stormwater violation under Article I carries the general penalty in § 1-16 through § 27-55, plus civil remedies the city can pursue independently: injunctions, mandamus actions, or recovering costs if the city itself is fined by the state or federal government for a permit violation traceable to a specific property owner. The director of stormwater management can also suspend or revoke an approved construction activity application under § 27-54 for noncompliance with notices or stop work orders.
Frequently Asked Questions
What redevelopment projects trigger Charleston's stormwater standards?
Who maintains stormwater drainage systems once they're built in Charleston?
Can a Charleston property owner appeal a denied stormwater application?
Sources & Official References
Other rules in Charleston
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Stormwater Management in Nearby Cities
How other cities in Charleston County handle stormwater management.