Illicit Discharge Detection and Elimination

As part of the stormwater program, the cities and county are required to identify and eliminate illicit discharges to the stormwater system.

Why is this important?

Rain water that flows into the stormwater system picks up pollutants such as dirt, fertilizers, pesticides, oil, and bacteria on its way to the nearest storm drain or creek. Unlike sewage, which is collected and treated at a wastewater treatment plant, anything that flows into a storm drain empties directly into the nearest stream or creek, normally without any treatment.

What is an illicit discharge?

Illicit discharge” means any direct or indirect non-stormwater discharge to the storm drain system.

Illicit connection” means any man-made conveyance that is connected to stormwater system without a permit, excluding roof drains and other similar type connections. Examples include sanitary sewer connections, floor drains, channels, pipelines, conduits, inlets, or outlets that are connected directly to the municipal separate storm sewer system.

Non-stormwater discharge” means any discharge to the storm drain system that is not composed entirely of stormwater.


City of Asotin County of Asotin City of Clarkston