Municipal separate storm sewer system (MS4) facility inventory

Staff cleaning after a spill at a municipal operations facility
Staff cleaning a spill at a municipal operations facility. Photo credit: Hanscom Air Force Base

The MS4 General Permit requires permittees to maintain an inventory of municipally owned facilities that contribute to stormwater pollution (MS4 General Permit Part III.D.6.a.). Examples of such facilities include:

  • composting,
  • equipment storage and maintenance facilities,
  • hazardous waste disposal facilities,
  • hazardous or solid waste handling and transfer facilities;
  • landfills,
  • parks,
  • pesticide storage areas,
  • public parking lots,
  • public golf courses;
  • public swimming pools,
  • public works yards,
  • recycling facilities,
  • salt storage areas,
  • vehicle storage and maintenance (e.g., fueling and washing) yards, and
  • materials storage yards.

In addition, the permittee must implement best management practices (BMPs) to reduce the impacts of these facilities to surface water (MS4 General Permit Part III.D.6.b.).


  • Facility inventory template - The MPCA's template for the Facility Inventory, which includes examples of types of facilities, facilities operations, pollutants associated with the operations, and BMPs.
  • Facility inventory template - City of Rochester's Facility Inventory template