Illicit Discharges: How to Identify & Report

Volunteer monitors, citizens, and anyone who recreates or works around waterbodies are likely to have seen something strange, but didn’t know what it was or why it was there.

During lunch at a February Alabama Water Watch monitoring training, the City of Auburn Watershed Division gave a presentation on how volunteers and citizens can detect, report, and help eliminate illicit discharge.

What is an illicit discharge?

An illicit discharge is the discharge or placement of anything other than stormwater into the storm sewer system.

Illicit discharge detection and elimination are one of the “five minimum control measures” required by the Alabama Department of Environmental Management (ADEM) in the City of Auburn’s stormwater permit. Other measures include: public education, construction site runoff control, post construction stormwater management, and pollution prevention.

Photo credit: Dusty Kimbrow, City of Auburn

It’s important to note that many cities, like the City of Auburn, have a municipal separate storm sewer system, or MS4. In these systems, unlike in a combined sewer system, there is not a treatment process between the source of the stormwater and when the water enters a waterbody.

What are some examples of illicit discharges?

  • Discharge of washwater (i.e. laundry water)
  • Discharge from a sewage pump wet well
  • Dumping of grass clippings in a creek or storm sewer
  • Discharge of sanitary sewage onto the ground
  • Washing of concrete, paint, mud, or other construction waste

What are signs to look out for to detect illicit discharges?
Although there is no single indicator that can be used to identify the source and origin of an illicit discharge, these indicators help City of Auburn Water Resource Management prioritize and refine their investigation.

Photo credits: Dusty Kimbrow, City of Auburn


If it has been more than three days since the last rain event, dry weather flow may be an indicator of an illicit discharge. Flow alone is not a strong indicator of an illicit discharge.


Photo credits: Dusty Kimbrow, City of Auburn
Photo credits: Dusty Kimbrow, City of Auburn
Photo credit: Dusty Kimbrow, City of Auburn


Some common descriptions of odors associated with illicit discharges are:

Septic, ammonia, or sewage odorSanitary sewer overflow, improperly connected sanitary sewer line, leaking septic tank
Rancid, sour, or pungent odorDecomposing organic matter, may be associated with glass clippings or other debris in stormwater
Rotten egg odorCan be indicator of hydrogen sulfide
Fuel or petroleum odorLeaking underground or above ground fuel tanks, improper disposal of petroleum products
Solvents or other cleaning solution odorWash activity including car washes, floor cleaners, pressure washing with chemical additives


Common examples of floatables are fecal matter, oily sheens, suds, and tissue paper.


Gray staining is an indicator of a recent or ongoing Sanitary Sewer Overflow (SSO) (left). Excessive algae growth is sometimes an indicator of an illicit discharge (right).

What do I do if I see an illicit discharge?


Call 911 if the discharge appears that it may be a threat to public health or safety, like a large fuel spill or hazardous waste spill.


In the City of Auburn, you can call the Water Resource Management Department at 334-501-3060 or email them at You can also contact the Non-Emergency Public Safety Line at 334-501-3100.

In other cities, you may contact a Watershed Resource Management Division, Health Department, or Sewer/Infrastructure Department.

Special thanks to the City of Auburn Watershed Division. All photos and content were provided by Dusty Kimbrow with the City of Auburn.