Water Quality

Achieving Safe, Clean Waterways for a Healthy and Vibrant Community

Approximately 760 miles of streams and 38 miles of Ohio River shoreline offer many opportunities to interact with water in Louisville and Jefferson County. The Municipal Separate Storm Sewer System (MS4) program was created to help maintain and improve the quality of those waterways by reducing the pollutant discharges that flow into them with stormwater runoff.

Rain and melting snow gather pollutants as the water runs off from manmade impervious surfaces such as buildings, rooftops, roads and driveways into the sewer system.

The Louisville MS4 program is regulated under a permit issued by the Kentucky Division of Water (DOW) to MSD and the cities of Anchorage, Jeffersontown, Prospect, Shively, St. Matthews and Louisville Metro with MSD as the lead administrative agency.

MSD implements the permit activities through a Storm Water Quality Management Plan (SWQMP) that functions as a guide to compliance with the MS4 permit.

The MS4 Permit program activities are divided into several program areas:

  • Illicit Discharge Detection and Elimination
  • Construction Site Runoff Controls
  • Post Construction Site Runoff Controls
  • Public Involvement and Outreach Programs
  • Facility Good Housekeeping and Pollution Prevention
  • Monitoring
  • Reporting and Program Assessment

Supporting Documents

Current MS4 Permit

Current SWQMP 

Current MS4 Annual Report