Porter County MS4

Porter County discharges polluted storm water to the surrounding bodies of water that lead to either Lake Michigan or the Kankakee River.  Polluted storm water?! Yes, all storm water that flows over land (especially land that is non-vegetated such as roads, parking lots, and even fertilized grass!) carries pollutants through the storm drains and to the public waterways.  Similar to how industrial facilities are required to comply with environmental permits, all municipalities with a population over 10,000 must comply with the MS4 General Permit under the Indiana Department of Environmental Management (IDEM). 

What is an MS4? This acronym stands for Municipal Separate Storm Sewer System.  There are two types of sewer systems: one for storm water and one for sanitary sewer.  The pipes that carry your grey water and sewage from your home lead to a treatment plant and release clean, non-potable water.  But the street storm water inlets do not lead to a treatment plant.  Rather, the pipes lead to a detention basin for pollutant settlement and then out to the nearby ditch or creek.  Because there is no treatment in place for storm water, municipalities are required to track and eliminate polluted discharges to the best extent practicable.  

Note that in Porter County, there is no sanitary sewer since the residents are located out of range of a treatment plant.  Most homes in Porter County are connected to a septic system, which internally treats sewage and releases clean water to the ground water table.  To learn more about septic systems, visit www.epa.gov/septic

Porter County is a Phase II MS4 under the EPA's NPDES Program, which means we qualified for the program that regulates smaller municipalities. To learn more about the MS4 program, check out www.epa.gov/npdes-stormwater-program

How does Porter County comply with this MS4 General Permit?  There are six Minimum Control Measures (MCMs) that guide the program: 

  • MCM 1&2: Public Education, Participation & Involvement
  • MCM 3: Illicit Discharge Detection & Elimination
  • MCM 4: Construction Site Runoff Control 
  • MCM5: Post-Construction Runoff Control
  • MCM 6: Pollution Prevention & Good Housekeeping

These permit requirements must be completed on an annual or 5-year permit cycle basis.  For example, this website helps Porter County reach its public education goal on a daily basis.  Active construction sites must be inspected several times a year to reach compliance.  At the end of the 5-year permit cycle, Porter County should have inspected 100% of all stormwater conveyance.  Each requirement creates an opportunity for us to improve water quality and inspiring others to do the same. 

If you have any questions on this information, please reach out to our office 219-465-3530 or email stormwater@porterco.org.