Storm Water Quality

Municipal Separate Storm Sewer System

The Town of Chesterton has been designated a Municipal Separate Storm Sewer System (MS4) by the Indiana Department of Environmental Management (IDEM).  An MS4 is defined as a conveyance or system of conveyances owned by a public entity that discharges to waters of the United States and is designed or used for collecting or conveying stormwater.


Regulated conveyance systems include:

  • Roads with Drains
  • Municipal Streets
  • Catch Basins
  • Curbs
  • Gutters
  • Storm Drains


  • Piping
  • Channels
  • Ditches
  • Tunnels
  • Conduits

Town of Chesterton’s MS4 boundaries are the same as the municipality’s corporate boundaries.

MS4s were regulated by 327 IAC 15-13 (Rule 13) from July 7, 2003 until December 18, 2021 when IDEM revised the regulations and converted to an administratively issued general National Pollutant Discharge Elimination System (NPDES) permit, which is known as the MS4 General Permit (MS4GP).

Chesterton's Storm Water Permit

The MS4 is permitted under the National Pollutant Discharge Elimination System (NPDES) program through the Indiana Department of Environmental Management (IDEM). MS4 permits are granted in 5-year cycles at the end of which the permit must be renewed. The Town of Chesterton’s 1st NPDES permit was granted in 2003. The permit was renewed in 2008, 2013, 2018 and 2023.

Storm Water Quality Management Plan (SWQMP)

This Stormwater Quality Management Plan (SWQMP) meets the requirements of the MS4GP, includes information about the MS4, and describes Best Management Practices (BMPs) and other provisions to reduce the discharge of pollutants from the MS4 into receiving waters.

Common Ground, Common Water - A Shared Priority
Video from Purdue University