Illicit Discharges

What is an Illicit Discharge?

Stormwater runoff from urbanized areas can transfer pollutants from the storm sewer system to lakes and streams. In order to protect water quality Federal, State, and Local governments regulate what can go down the storm drain. In most cases, only rain is allowed down the drain.

Any discharge to a municipal separate storm sewer that is not composed entirely of stormwater is considered an illicit discharge. These discharges can often be detected when a storm drain has flow during dry weather.

As an MS4, the University is required to prohibit discharges of non-stormwater as well as detect and eliminate any discharges that may occur.



While rain is only allowed down the storm drain, there are certain discharges permissible by the University’s MS4 Permit that have been determined to not contribute substantial pollutants to the environment. These allowed non-stormwater discharges include:

  • Water Line Flushing
  • Landscape Irrigation
  • Diverted Stream Flows
  • Rising Ground Waters
  • Uncontaminated Ground Water Infiltration
  • Uncontaminated Pumped Ground Water
  • Discharges from Potable Sources
  • Air Conditioner Condensate
  • Irrigation Water
  • Springs
  • Water from Crawl Space Pumps
  • Footing Drains
  • Lawn Watering
  • Individual Car Washing
  • Natural Flows from Riparian Habitat and Wetlands
  • Dechlorinated Swimming Pool Discharges
  • Street Wash Water
  • Discharges or Flows from Fire Fighting Activities
Fire Hydrant Water Line Flushing Landscape Irrigation Discharges or Flows from Fire Fighting Activities


    Illicit Discharges vs Spills

    While an illicit discharge is a discharge of non-stormwater to the storm sewer system, a spill is any release of material that threatens human health or the environment. A spill can become an illicit discharge once it enters the storm sewer system.


    Illicit Discharge of Sediment to Stormdrain Illicit Discharge from Storm Sewer to Stream
    Paint/Dye Spill Grease Spill



    The University’s goal is to prevent spills from occurring and to contain them if they do occur in order to prevent an illicit discharge. Visit our Spill Plans and Response Section to learn more about spills, how the University responds, and what resources are available. See below to learn how to identify and report an illicit discharge.



    Illicit Discharges can be most easily identified when flow is observed during dry weather. 

    These flows can contribute pollutants to the storm sewer system by direct or indirect discharge.

    A direct discharge is one that enters the storm sewer directly through a pipe or drain, is usually continuous or intermittent, and is usually caused by an unintentional sewage cross connection or an intentional bypass known as a straight pipe.  

    An indirect discharge is one that is generated outside the storm sewer system and enters through an inlet (storm drain) or joints in pipes and can be intermittent or temporary. These typically enter the storm sewer system via groundwater seepage after rain events, spills, dumping, outdoor washing activities, or irrigation runoff.

    Activities that can produce a discharge include:

    • Outdoor Washing Activities: Vehicles, Surfaces, Equipment, Buildings
    • Parking Lot Maintenance
    • Vehicle/Equipment Fueling
    • Vehicle Maintenance/Repair
    • Landscaping/Grounds Care
    • Sewer Blockage/Maintenance
    • Construction
    • Erosion

    Information for this section provided by:
    Brown, E., & Caraco, D., (Center for Watershed Protection) & Pitt, R. (University of Alabama) (2004, October). Illicit Discharge Detection and Elimination: A Guidance Manual for Program Development and Technical Assessments. EPA Cooperative Agreement.


    Common Illicit Discharges/Spills




    Sediment on sidewalk caused by erosion from heavy rains and recent construction Sediment laden discharge caused by water line break
    Sediment deposits along road caused by water line break Mud tracked on roadway from construction site
    Mud on roadway from poorly maintained construction entrance Discharge of sediment from improper construction site cleaning practices
    Discharge of sediment from improper dewatering practices Discharge of sediment laden water from improper construction dewatering practices
    Discharge of sediment caused by erosion due to poor stabilization of area post construction  




    Equipment hydraulic fluid leak Fluid leak from burst garbage truck hydraulic line
    Overflowing used cooking oil container Improper disposal of used cooking oil in parking lot



    Floor Cleaners/Wax


    Floor wax/stripper discharged towards storm drain Spilled floor wax/stripper at loading dock
    Floor wax/stripper discharged directly into storm drain Floor wax/stripper at storm drain


    Sanitary Sewage


    Solids overflowing from open sewage cleanout adjacent to building Sewage overflowing from open cleanout
    Sanitary sewer in stormwater flow Sanitary sewer overflow in stream
    Overflowing sanitary sewer manhole Sanitary sewage flowing over asphalt pavement


    Leaking Dumpsters/Compactors


    Waste leaking from compactor unit directly into storm drain Dumpster leaking directly into storm drain
    Leachate discharging from dumpster area  



    Chilled Water/Steam


    Steam coming from stormwater inlet Steam coming from stormwater curb inlet



    Garbage Truck Spills


    Concentrated floor wax/stripper spilled from garbage truck during routine pickups Concentrated dye spilled from garbage truck during routine pickups
    Garbage truck leachate spilled during compaction  



    Concrete (dust/slurry/rinsate)


    Slurry from concrete coring project entering storm drain Staining from concrete spill rinsate entering storm drain
    Overflowing concrete washout basin at construction site Waste concrete and rinsate flowing along curb from construction site



    Paint/Drywall Spackle


    Drywall spackle poured down trench drain Paint poured down storm drain


    Litter & Debris


    Litter impacting storm drain at campus loading dock from nearby dumpsters Litter in storm drain captured by water quality unit
    Litter and debris in storm drain inlet Litter and debris along curbing
    Grass clippings left on roadway after mowing  Grass clippings clogging storm system



    Only clean rainwater and the few exceptions noted above can go down a storm drain. If you see something other than clean water entering a drain or with the potential to enter a drain if it rains, please report it. Any substance entering a storm drain has the potential to harm water quality and needs to be stopped.

    To report an Illicit Discharge simply access our Illicit Discharge Reporting Tool via the 
     Report an Illicit Discharge Button 
     in the top left sidebar.

    This tool allows you to submit information regarding an observed illicit discharge or concern such as:

    • The date and time the discharge was observed
    • A brief description of the discharge
    • A mapped location of where the discharge was observed
    • A general description of the location
    • Relevant photos of the issue

    If it’s an emergency or if the situation is deemed urgent, please contact our Spill Response Section at 859-323-6280 (8am – 5pm) or call 859-257-UKPD (After Hours).

    Once an illicit discharge had been reported, Environmental Quality Management Department (EQM) will investigate to verify the discharge, track down the source, identify the responsible party, and work to eliminate the discharge. The investigation and findings will be documented and included in our Annual Report.


    University Response

    The University has a program in place to prohibit illicit discharges, detect and address any illicit discharges that occur, and to allow the public the opportunity to report illicit discharges. Our Illicit Discharge Detection and Elimination Manual provides detailed information about our response to illicit discharges and addresses the requirements of our MS4 Permit.



    The following map provides the location and a brief description of the Illicit Discharges that have been reported on campus over the last year:


    A more detailed map for discharge investigation tracking, verification, and details is available for employees that have been granted access.