Protecting Water Resources

There are numerous human activities that increase the amount of pollutants that stormwater picks up and discharges into the ground or local surface waterbodies.  An illicit discharge is when unauthorized non-stormwater discharges are leaked, drained, poured, improperly connected by pipes, or spilled onto city property, right of way, or border easements that may reach a city stormwater system.

Mop water being discharged into a drywell.

Examples of illicit discharges observed by city staff include:

  • Motor oil and other automotive liquids
  • Concrete wash-out
  • Latex or oil-based paints
  • Sewer waste
  • Trash
  • Cooking grease
  • Pet waste
  • Excessive sediment from construction activities or material piles

The city is diligent in responding as quickly as possible to discovered or reported illicit discharges.  In 2024, the city updated its Illicit Discharge Detection and Elimination (IDDE) program plan which outlines how the city identifies and responds to illicit discharges.  

For more information, please see the city’s IDDE Program Plan here: Spokane Valley IDDE Program Plan 2025