Illicit Discharge Detection & Elimination

An illicit discharge is any discharge to the storm sewer system that is not composed entirely of stormwater and is not a discharge that is authorized by a permit issued by the State of Colorado. The storm sewer system includes roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, man-made channels and storm drains. It can be either an enclosed pipe or an open channel. The City of Cañon City is required by its State permit to develop, implement and enforce a program to detect and eliminate illicit discharges.

Defining Illicit Discharges

Drainage channels and ditches are considered part of the storm sewer system - dumping trash in them can be considered an illicit discharge.

Not all water coming from a storm drain pipe during dry weather is an illicit discharge. Field testing is needed to determine the source.

Water quality testing is done by department staff on all dry weather flows. If the flow is determined to be an illicit discharge it is traced to its source and appropriate action is taken.


Illicit discharges may enter the storm sewer system either through direct connections (i.e. wastewater piping mistakenly or deliberately connected to the storm sewer) or indirect connections. Indirect connections can include leaks from sanitary systems, spills which are collected by storm drains, or materials such as paint or used oil dumped directly into a storm drain.

Potential Sources of Illicit Discharges

  1. Automobile Maintenance & Operation
  2. Landscaping / Yard & Home Maintenance
  3. Sanitary Wastewater
  4. Other
  • Engine degreasing
  • Improper disposal of used oil, antifreeze and other automotive fluids
  • Leaking automotive fluids
  • Leaky underground storage tanks
  • Radiator flushing
  • Wastewater from commercial car washes

Low-Risk Discharges Not Requiring State Permits

These discharges will not be enforced upon unless they pose a significant risk to water quality:

  • Agricultural stormwater runoff
  • Air conditioning condensation
  • Dechlorinated swimming pool and hot tub discharges
  • Discharges from potable water sources as long as it has not been used in any additional process
  • Diverted stream flows
  • Dye testing
  • Foundation, footing and roof drains
  • Individual residential car washing
  • Irrigation return flows
  • Landscape irrigation and lawn watering
  • Springs, flows from riparian habitats and wetlands and rising ground waters
  • Uncontaminated groundwater infiltration and uncontaminated pumped groundwater except that from construction activities
  • Water from crawl space pumps as long as it is uncontaminated
  • Water from emergency fire-fighting activities
  • Water incidental to street sweeping
  • Water line flushing