Guidance for meeting bacteria TMDL MS4 permit requirements

Total Maximum Daily Loads (TMDLs)

Escherichia (E). coli is an indicator bacteria, meaning that it indicates the potential presence of disease causing pathogens that can be harmful to human health. Currently there are X TMDLs that include MS4 WLAs for bacteria. Click here to link to MPCA's impaired waters website. A map illustrating U.S. EPA-approved listings for E. coli and fecal coliform is shown on the right (insert map).

The MS4 permit requires permittees that have an applicable wasteload allocation (WLA) for bacteria to:

1. Maintain a written or mapped inventory of potential areas and sources of bacteria (e.g., dense populations of waterfowl or other birds, dog parks) (Permit requirement 18.14).
2. Maintain a written plan to prioritize reduction activities to address the areas (Permit requirement 18.15).