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Illicit Discharge Detection and Elimination (IDDE)

What Types of Discharges to the Storm Drain System are Prohibited?

The following table lists some of the prohibited and allowed discharges to the storm drain system:

Prohibited Discharges:

Allowed Discharges:

Industrial process water
Water utility line flushing
Commercial car wash wastewater
Runoff from firefighting
Sanitary sewer flows
Landscape irrigation
Wash-down of loading areas
Uncontaminated ground water infiltration
Wastewater treatment plant effluent
Discharges from potable water sources
Dumping of liquid waste
Dechlorinated pool water
Chlorinated pool water
Street wash water from cleaning/maintenance (excluding street sweeper water waste)
Water softener brine backwash
Residential car washing
Used oil
Air conditioning condensation

What are Indications of Illegal/Illicit Discharges to the Storm Drain System?

The following table lists some of the physical indicators that may signal an illicit discharge; physical indicators are those that can be observed or sensed during dry weather field screening and routine inspections:

Unusual color or cloudiness
Strong pungent or musty odor
Floating debris
Surface scum or foam
Oil sheen
Dead vegetation or inhibited growth
Dead animals
Stains on channel bottom or sides
Pipe corrosion


 North Central Texas Council of Governments | 616 Six Flags Drive P.O. Box 5888 Arlington, TX 76005-5888
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