Regulations & NPDES
NPDES Stormwater Permit
The City of Wilmington is required to implement and maintain compliance with a federal National Pollutant Discharge Elimination System (NPDES) Phase II Stormwater Permit, issued under the Clean Water Act. This federally mandated program regulates stormwater discharges from municipal separate storm sewer systems (MS4s) serving urban and suburban areas.
The purpose of the NPDES Stormwater Program is to reduce the discharge of pollutants in stormwater runoff in order to:
- Protect and restore surface water quality
- Safeguard drinking water supplies and public health
- Preserve aquatic habitat and natural resources
- Promote pollution prevention and environmental stewardship throughout the community
The City’s NPDES permit requires the development, implementation, documentation, and ongoing evaluation of a comprehensive Stormwater Management Program, organized around six federally required minimum control measures:
- Public Education and Outreach
- Public Involvement and Participation
- Illicit Discharge Detection and Elimination (IDDE)
- Construction Site Stormwater Runoff Controls (1–5 acres)
- Post-Construction Stormwater Management Controls
- Pollution Prevention and Good Housekeeping for Municipal Operations and Facilities
To meet these requirements, the City must maintain a detailed NPDES Stormwater Management Plan (SWMP). The SWMP serves as the City’s formal compliance framework and establishes enforceable practices, procedures, ordinances, interdepartmental responsibilities, and measurable performance standards that must be implemented and documented by City staff on an ongoing basis.
The City is required to prepare and submit a comprehensive Annual NPDES Report to the North Carolina Department of Environmental Quality (NCDEQ), documenting program activities, compliance status, and progress toward permit requirements for each reporting year.
In addition to annual reporting, the City is subject to periodic compliance audits and inspections conducted by NCDEQ and/or the U.S. Environmental Protection Agency (EPA). These audits evaluate the City’s adherence to permit conditions, the adequacy of program implementation, and the effectiveness of the Stormwater Management Plan. Noncompliance may result in formal enforcement actions, penalties, and/or mandated corrective measures.
The City’s NPDES Phase II Stormwater Permit is renewed on a five-year cycle, requiring a state/EPA audit, ongoing program evaluation, development of new Stormwater Management Plans, coordination across multiple City departments, and adaptation to evolving federal and state regulatory requirements.
The city will be moving to a Phase I permit with additional requirements in the near future.
Stormwater Ordinances
Chapter 12 (Utilities) of the city code outlines requirements for pet waste, yard debris, and the illegal discharge of pollution into the storm drainage system and our waterways. The Stormwater Code Compliance Officer enforces these regulations; reports can be made to the Stormwater Pollution Hotline or Online.
Pet Waste Ordinance
Yard Waste/Debris Ordinance
Illicit Discharge Ordinance
Land Development Ordinance
Chapter 18 (Land Development) of the city code details regulations for managing stormwater for new development and re-development within the city. The land development code is enforced by the planning and engineering divisions. Information on city design standards, post-construction requirements, checklists, and other materials can be found at the following links: