Post-Construction Stormwater

The objective of the Post-Construction Program is to protect surface waters from the impacts of stormwater runoff from developments after the construction process is complete.  The Post-Construction Program applies to only certain parts of the state and is implemented by DEMLR in some areas and by local governments in other areas.  The Interactive Permitting Map indicates whether a post-construction program applies at any address in North Carolina and, if so, which program applies and whether the program is adminstered by DEMLR or a local government.  After determining which program applies, the Summary of Post-Construction Programs explains the requirements of each program.

Please note that DEMLR also has an Erosion and Sediment Control Program that applies to development activities during the construction process. 

How to determine if a project is high or low density

The requirements for high and low density projects are codified in 15A NCAC 02H .1003.  

Low density projects must meet ALL of the following criteria:

  • Be designed with a built upon area (BUA) percentage below the threshold that pertains to the applicable stormwater program (see Chapter E-1 of the Stormwater Design Manual); 
  • Maximize dispersed flow through vegetated areas and minimize channelization of flow; AND
  • Transport stormwater that cannot be dispersed via vegetated conveyances (a small amount of piping is allowable for erosion control or driveway crossings when it cannot be avoided).

High density projects (projects that don't meet the low density criteria) must meet either the runoff treatment or volume match requirements (see Chapter A-1 of the Stormwater Design Manual).

  • Runoff treatment requires all of the stormwater generated from new BUA surfaces to be treated by a Primary SCM.
  • Volume match is achieved by demonstrating that the annual runoff volume after development is no more than 10% higher than the annual runoff volume before development (5% in areas subject to SA waters requirements).  We are currently revising Storm-EZ, which is a tool that can be used to demonstrate compliance with this option.  We plan to have an updated version of Storm-EZ with instructions posted by the end of 2019.

For either high density option, projects that increase the BUA will need to implement structural SCMs. Each SCM must meet all of the General Minimum Design Criteria (MDC) in 15A NCAC 2H .1050 and the SCM-specific MDC in the appropriate section of 15A NCAC 02H .1051-.1062.  The Stormwater Design Manual provides guidance on how to meet the MDC.

How to apply to DEMLR for a post-construction permit

The process to apply to DEMLR for a post-construction stormwater permit:

  1. Design the project to meet the requirements of the post-construction program that applies.
  2. Select one of the Permitting Options
  3. Complete all of the required forms and prepare all of the required documentation. 
  4. Submit the project to the appropriate office for review.

Applications for projects outside of the 20 coastal counties should be sent to the DEMLR Central Office at:
                                                            
Division of Energy, Mineral & Land Resources
Stormwater Program                                     
1612 Mail Service Center                                                                                              
512 North Salisbury Street                                                                                           
Raleigh, NC 27699-1612

Applications for projects in the 20 coastal counties should be sent to the appropriate Regional Office.

Permit Modification, Transfer, and Renewal Forms

New Permit / Major Modification Form – for modifications to a project that do not qualify as minor modifications ($505 fee for standard permitting, express fee varies)

Minor Modification Form – for modifications to a project with no BUA increases or SCM changes (no fee)

Permit Transfer Application Form – for permits that are being transferred from one responsible party to another ($505 fee)

Permit Information Update Form – for administrative changes to project name, permittee contact info, legal corporation name not due to change of ownership (no fee)

Permit Renewal Form – for renewals of high density permits (required every 8 years, $505 fee)