CSM Illicit Discharge Detection & Elimination (IDDE)

Question 1

Which federal regulatory program is the primary driver requiring MS4 operators to develop and implement Illicit Discharge Detection and Elimination (IDDE) programs?

Accepted Answer

NPDES Phase I and Phase II Stormwater Permit Program

Answer

The NPDES Phase I and Phase II Stormwater Permit Program, under the Clean Water Act, requires regulated MS4 operators to develop IDDE programs as one of six minimum control measures.

Question 2

Which of the following is correctly classified as an illicit discharge to a municipal separate storm sewer system (MS4)?

Accepted Answer

Residential car washing wastewater entering a storm drain

Answer

Residential car washing wastewater contains soaps, oils, and other pollutants that are prohibited discharges to the storm sewer; it is considered illicit because it is not stormwater.

Question 3

What is the first critical step in establishing a municipal IDDE program?

Accepted Answer

Creating and maintaining a complete map of the storm sewer system

Answer

A complete storm sewer system map is the foundation of any IDDE program because field staff must know where pipes go and where outfalls are located before investigating potential illicit connections.

Question 4

Which water quality indicator is most commonly used in field screening to detect the presence of sanitary sewage contamination in stormwater outfall flows?

Accepted Answer

Fecal coliform or E. coli bacteria

Answer

Fecal coliform and E. coli are reliable biological indicators of human sewage contamination and are the standard parameters used to confirm sanitary sewer cross-connections in IDDE screening.

Question 5

What is the primary purpose of conducting dry-weather screening at storm drain outfalls?

Accepted Answer

To detect non-stormwater flows that may indicate illicit connections or discharges

Answer

Dry-weather screening identifies outfalls with unexplained flows during periods of no recent rainfall, which is a primary indicator of potential illicit connections to sanitary lines or illegal dumping.

(CSM) Certified Stormwater Manager Practice Test

(CSM) Certified Stormwater Manager Practice Test

CSM Illicit Discharge Detection & Elimination (IDDE)