Illicit Discharge Screening

Goal & Purpose

One of the six minimum measures of an MS4 program is Illicit Discharge Detection and Elimination (IDDE).

The goal of IDDE is to locate non-stormwater discharges – particularly chronic discharges – entering the storm drain system and to eliminate them. It is not uncommon to find that older buildings plumbed wash waters and such to a storm drain, which from there entered a stream. It’s also not uncommon to find regular washing outdoors that drains the wash water to storm drains.

Types of Innocuous Waters

There are a number of innocuous, non-stormwater discharges that may be discharged to the storm drain, but otherwise non-stormwater discharges are restricted from entering storm drains. Some of the innocuous waters are:
  • Air conditioning condensation
  • Firefighting activities
  • Groundwater infiltration to storm drains
  • Landscape irrigation or lawn watering with potable water or re-purified water
  • Non-commercial washing of vehicles
  • Other uncontaminated water source
  • Swimming pools (if dechlorinated)
  • Water line flushing or other potable water sources
Our screening activities are periodic only, and so we must rely on reports from you – citizens – and from other city staff to find non-stormwater discharges. Call us if you see wash waters being discharged into or toward storm drains at 615-848-3200.

Available Reports