Despite the somewhat risqué title, the subject of this article is connections or discharges from sewer systems to stormdrain systems. When this happens, untreated sewage flows into streams, rivers, lakes and the ocean. Illicit connections can also work the other way – a storm drain can be connected to the sewer system. The problem in that case is greatly increased flows during rainfall events, leading to sewer overflows. In either case, the sewer and storm drain systems are intentionally or inadvertently connected, resulting in pollution.
An illicit discharge is defined as any discharge to the municipal separate storm sewer system that is not composed entirely of storm water, except for discharges allowed under a NPDES permit or waters used for firefighting operations. These non-stormwater discharges occur due to illegal connections to the storm drain system from homes, business or commercial establishments. As a result of these illicit connections, contaminated wastewater enters into storm drains or directly into local waters before receiving treatment from a wastewater treatment plant. Illicit connections may be intentional or may be unknown to the business owner or homeowner and often are due to the connection of floor drains to the storm sewer system. Additional sources of illicit discharges can be failing septic systems, illegal dumping practices, and the improper disposal of sewage from recreational practices such as boating or camping.
Illicit discharge detection and elimination (IDDE) programs are designed to prevent contamination of ground and surface water supplies by monitoring, inspection and removal of these illegal non-stormwater discharges. An essential element of these programs is an ordinance granting the authority to inspect properties suspected of releasing contaminated discharges into storm drain systems. Another important factor is the establishment of enforcement actions for those properties found to be in noncompliance or that refuse to allow access to their facilities.
Many cities and counties have IDDE programs. Typical procedures for detecting illegal connections to the Storm Sewer System are:
EPA has prepared a model ordinance which includes language to address illicit discharges in general, as well as illicit connections from industrial sites. The language is borrowed from a number of ordinances and communities will need to assess what enforcement methods are appropriate for their area. EPA has also prepared a Guidance Manual for Identifying and Eliminating Illicit Connections to Sewer Systems.
Surfrider Foundation, through its Blue Water Task Force program, has helped to uncover several instances of illicit connections, including at Larrabee State Park in Washington and in Newport and Cannon Beach, Oregon.
Illicit Discharges (U.S. EPA)
Guidance Manual for Identifying and Eliminating Illicit Connections (U.S. EPA)
Illicit Connection Amnesty Program (Town of Burlington, MA)
Illicit or Illegal Connections to the Storm Sewer System (City of Cumming, GA)
ILLICIT CONNECTIONS AND PROHIBITED DISCHARGES (Municode, Orange County, CA)
Illicit Discharge Detection and Elimination - A Guidance Manual (U.S. EPA, Center for Watershed Protection)
Stories about Getting to Clean Water: Stormwater Sleuths Solve the Mystery of the Putrid Pipe - Pullman’s hunt for the elusive, illicit discharge (Washington Department of Ecology)