Aquifer Protection Section
Groundwater Protection Unit :: Stormwater Injection
This page contains information about stormwater drainage wells authorized by the new injection well regulations effective May 1, 2012. Detailed information about stormwater management is available from the DWQ Wetlands and Stormwater Branch and the DWQ Stormwater BMP Manual.
For additional information contact Thomas Slusser at 919-807-6412.
Stormwater injection is the emplacement of stormwater into the subsurface via a well, subsurface distribution system, or sinkhole and other natural depressions. Certain stormwater infiltration systems meet the regulatory definition of an injection well. Injection wells are regulated by the Underground Injection Control (UIC) Program.
Is stormwater injection legal in North Carolina?
Injection well regulations adopted in 1997 prohibit stormwater injection. However, revised regulations effective May 1, 2012, allow stormwater injection under certain conditions. This revision was made to eliminate a regulatory conflict between the 1997 injection well rules prohibiting stormwater injection and stormwater BMPs that promote stormwater infiltration as a means of protecting surface water quality and enhancing groundwater recharge.
Is stormwater injection an environmental concern?
Many of the same concerns about stormwater runoff entering surface water bodies also apply to groundwater, which provides approximately half North Carolina's water supply needs. Stormwater runoff may contain automotive fluids, metals, nutrients, salts, fertilizers, pesticides, and microorganisms. Proper treatment and infiltration of stormwater is an important part of protecting North Carolina's groundwater resources.
What regulations apply?
Injection well rule 15A NCAC 02C .0227 specifies that stormwater injection is only allowed to occur via rooftop runoff infiltration systems or infiltration systems that are designed and operated in accordance with federal or state stormwater regulations. Untreated stormwater shall not be emplaced directly into any aquifer and the operation of any stormwater injection well cannot result in the violation of any groundwater quality standard specified in 15A NCAC 02L.
Stormwater infiltration systems subject to State and local government stormwater regulations do not need a separate permit from the UIC Program. Rather, a notification form shall be submitted to the UIC Program in order to comply with federal injection well inventory reporting requirements.
Which types of stormwater BMPs need to be reported as injection wells?
Stormwater infiltration systems that use subsurface distribution systems, drain tiles, perforated or open-bottom pipes, or similar mechanisms designed emplace stormwater into the subsurface. Many different system designs are possible. The following table lists various types of stormwater BMPs and indicates which ones need to be reported to the UIC Program.