Town Of Whitestown
 Stormwater Management 

Illicit Discharge Detection and Elimination

The illicit discharge detection and elimination (IDDE) minimum control measure consists of best management practices (BMPs) and program elements that focus on finding and addressing non-stormwater discharges and/or non-permitted discharges that may be entering the municipal separate storm sewer system (MS4).


Regulated MS4s are required to establish plans to detect and eliminate illicit discharges including discharges not composed entirely of stormwater. They must map all outfalls from the storm sewer system to surface waters (not only from pipes, but also from road ditches, swales and other stormwater carriers), and must inform public employees and the community about the hazards of illegal discharges and improper waste disposal. Further, illicit discharges to the storm sewer system must be prohibited by ordinance or regulation, and the prohibition must be enforced.


The MS4 is required to develop and maintain a map showing: the location of all outfalls and the names and location of all surface waters of the State that receive discharges from those outfalls. By March 9, 2010, the preliminary boundaries of the permittee's storm sewersheds should be determined using GIS or other tools, even if they extend outside of the urbanized area. This will help facilitate trackdown of illicit discharges. When grant funds are made available, a map of the sewer lines and storm sewer system should be completed.


The MS4 is required to field verify outfall locations and conduct an outfall reconnaissance inventory that addresses every outfall within the MS4 designated area at least once every five years.


An IDDE program should also address non-stormwater discharges, including illegal dumping. The program must include: procedures for identifying priority areas of concern (geographic, audiences, or otherwise); a description of priority areas of concern, available equipment, staff, funding, etc.; procedures for identifying and locating illicit discharges (trackdown); procedures for eliminating illicit discharges; and procedures for documenting actions.


In certain areas that have current Watershed Improvement Strategies and/or Total Maximum Daily Load (TMDL) requirements, the regulated community may also be required to undertake additional activities such as: completing entire system mapping by January 8, 2013; and developing an on-site wastewater system inspection, maintenance and rehabilitation program (including the necessary legal authority to enforce the program). The details associated with these additional requirements are further described, and should be referenced, in the SPDES General Permit for Stormwater Discharges from MS4s.

Selected Activities and BMPs:

To meet the IDDE program requirements, the MS4 has selected the following Best Management Practices (BMP's) and activities to ensure the reduction of all pollutants of concern in stormwater discharges to the maximum extent practicable.

Outfall Mapping

Description of BMP/Activity:
Create and maintain a map of all storm sewer system outfalls and identify the names of receiving waterbodies.
Staff, Agency, and/or Organization Reponsible for Completing this Activity:
Frequency of Activity:
  • Program Development: Single Occurrence (Includes Updates As Needed)
  • Implementation: Single Occurrence (Includes Updates As Needed)
Status - Program Development:
[X] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[ ] On-Going - This activity will be undertaken throughout all years of the permit.
Status - Implementation:
[ ] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[X] On-Going - This activity will be undertaken throughout all years of the permit.

Field Verify Outfall Locations

Description of BMP/Activity:
Field verify outfall locations to insure they exist and are still a functioning part of the storm sewer system. During this activity, previously unknown outfalls may be identified.
Staff, Agency, and/or Organization Reponsible for Completing this Activity:
Frequency of Activity:
  • Program Development: On-going/Continuous
  • Implementation: On-going/Continuous
Status - Program Development:
[ ] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[X] On-Going - This activity will be undertaken throughout all years of the permit.
Status - Implementation:
[ ] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[X] On-Going - This activity will be undertaken throughout all years of the permit.

Illicit Discharge Detection and Elimination (IDDE) Law or Ordinance

Description of BMP/Activity:
Draft, adopt and enforce a stormwater management ordinance or other regulatory mechanism to prohibit illicit discharges.
Staff, Agency, and/or Organization Reponsible for Completing this Activity:
Frequency of Activity:
  • Program Development: Single Occurrence (Includes Updates As Needed)
  • Implementation: Single Occurrence (Includes Updates As Needed)
Status - Program Development:
[X] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[ ] On-Going - This activity will be undertaken throughout all years of the permit.
Status - Implementation:
[ ] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[X] On-Going - This activity will be undertaken throughout all years of the permit.

IDDE Hotline

Description of BMP/Activity:
Establish a hotline by telephone, as a web-based tool, or by other means where the general public can contact the MS4 to report suspected IDDE issues
Staff, Agency, and/or Organization Reponsible for Completing this Activity:
Frequency of Activity:
  • Program Development: Single Occurrence (Includes Updates As Needed)
  • Implementation: Single Occurrence (Includes Updates As Needed)
Status - Program Development:
[X] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[ ] On-Going - This activity will be undertaken throughout all years of the permit.
Status - Implementation:
[ ] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[X] On-Going - This activity will be undertaken throughout all years of the permit.

Combined Sewer and/or Sanitary Sewer Overflow Program

Description of BMP/Activity:
Develop and implement a program to manage the effect of excess stormwater runoff on sanitary and/or combined sewer overflows. Specific types of activities may include, but are not necessarily limited to: survey and corrective measures for inflow and infiltration, identification of storm water connections to sanitary sewer systems, infrastructure replacement, etc
Staff, Agency, and/or Organization Reponsible for Completing this Activity:
Frequency of Activity:
  • Program Development: On-going/Continuous
  • Implementation: On-going/Continuous
Status - Program Development:
[ ] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[X] On-Going - This activity will be undertaken throughout all years of the permit.
Status - Implementation:
[ ] Completed - This activity has been completed
[ ] Short-Term - This activity will be accomplished within the current reporting year.
[ ] Long-Term - This activity will be accomplished within the 3 to 5 year permit cycle.
[X] On-Going - This activity will be undertaken throughout all years of the permit.

Measurable Goals:

Regulated communities are required to collect and report information about the development and implementation of their stormwater program. Specific information that the MS4 is required to collect is generally included in the Annual Report and may also be reflected in related Self-Assessments (as applicable). MS4s are also required to identify "Measurable Goals" that will help them evaluate accomplishments and progress over time. The following "Measurable Goals" have been specifically identified for this Minimum Control Measure:

  • Percent completion of outfall mapping
  • Number and percent of outfalls mapped
Program Accomplishments:

Activities and BMPs that have been accomplished to date for this Minimum Control Measure are included within the required MS4 Stormwater Annual Report form and Municipal Compliance Certification. Copies of these documents can be found at the following link (Annual Reports). Copies of various documents and specific products relating to this minimum control measure are included under "Related Documents".


A summary of the effectiveness of this program, associated BMPs, activities and an assessment of measurable goals can be found under the heading "Program Reporting and Effectiveness".

Other Related Documents:
Whitestown IDDE Law (PDF - 43.9 KB)
Stormwater System Map (PDF - 6.2 MB)