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FAQ: E. coli TMDL

E. coli monitoring from bridge
Environment, Great Lakes, and Energy

FAQ: E. coli TMDL

When a water quality standard is exceeded, the Federal Clean Water Act requires Michigan to address pollution issues with either a Total Maximum Daily Load (TMDL) or by fixing the problem through other means.  For some issues, a remedy is already in progress to reduce pollution.  This is not the case for E. coli across the state.  The E. coli TMDL will provide a framework for restoration of water quality.

  • The Integrated Report is a document where the state of Michigan reports on the status of surface water quality to the public and the United States Environmental Protection Agency (USEPA). It contains a list of waters that do not meet the designated uses or Water Quality Standards (WQS) and the specific methods Michigan uses to evaluate data (Assessment Methodology). The Department of Environment, Great Lakes, and Energy (EGLE) submits the Integrated Report every two years (2020, 2022, etc.) as part of its obligations under the federal Clean Water Act. The USEPA approves the required portions of the Integrated Report, including the list of waters that are impaired by a pollutant and will require a Total Maximum Daily Load (TMDL).  Impaired waters needing TMDLs are in Appendix C of the Integrated Report.

  • If the E. coli levels in a water body exceed Michigan’s WQS (at a frequency described in the applicable Assessment Methodology section of the Integrated Report) then Michigan must develop a plan known as a TMDL. TMDLs set specific numeric targets and provide a framework for addressing E. coli pollution problems with a goal of meeting the WQS.

  • The TMDL watershed is the area that drains into the impaired water body. Facilities and municipalities in this area, or that discharge to the impaired water body either directly or indirectly, are subject to the TMDL. Layers showing the approved TMDL watersheds and draft addendum area (if applicable) are viewable on the MiEnviro Site Map Explorer and the interactive map at

  • Because EGLE does not currently know the full extent of E. coli impairments in Michigan, the TMDL will be updated to include new impaired waters as we find them based on future monitoring. The statewide TMDL will be updated every two years, consistent with the Integrated Report schedule, by adding waters listed in an addendum. A draft TMDL addendum containing proposed additional water bodies will be available for review and comment concurrent with the Integrated Report. Once approved by the USEPA, the waters identified in the addendum are part of the statewide E. coli TMDL.

  • EGLE will notify permittees of their proposed inclusion in the TMDL using contact information in MiEnviro. Additionally, EGLE maintains an e-mail notification service for Integrated Reporting and TMDL news. This service is used for the announcement of relevant public comment periods, availability of draft documents, TMDL approvals, and water quality monitoring announcements. To sign up for notifications, click on the envelope icon on The EGLE Environmental Calendar will also be used to alert the public of the Integrated Report changes.

  • Only comments regarding the newly proposed impaired water bodies in the draft TMDL addendum (2020, 2022, etc.) will be addressed, as appropriate. This includes comments on the extent of the TMDL watershed and the basis for the impairment decision.

  • The E. coli Pollution and Solution Mapper is an interactive mapping system maintained by EGLE, which allows users to enter their address and determine if their area is covered by an E. coli TMDL or a draft addendum (if applicable), as well as view information on potential sources and monitoring data. MiEnviro also has USEPA approved TMDLs as part of the Site Map Explorer tool. Additionally, if you are a permittee, you can contact your local EGLE Water Resources Division staff. If you are unable to use one of our mapping systems, please contact the Environmental Assistance Center at 800-662-9278 or

  • All permittees discharging to waters included in the E. coli TMDL are grouped by permit type (such as sanitary wastewater, industrial storm water, municipal storm water, concentrated animal feeding operations). As permits are reissued, language or requirements may be added to be consistent with the TMDL, per federal requirements. The MiEnviro Site Map Explorer can be used to search for publicly available information on any facility.

  • The TMDL describes the regulatory and voluntary ways that nonpoint sources of pollution can be corrected. EGLE lacks direct regulatory authority for most nonpoint sources, so EGLE and stakeholders must work together with other agencies and groups to solve these problems. Links to funding sources for stakeholders to use in helping to tackle the problem of nonpoint sources of pollution can be found at and For more information on nonpoint sources, please contact EGLE’s Nonpoint Source staff.

  • Local health departments have authority over on-site septic systems that serve individual homes, although EGLE does have oversight over the design and construction of larger systems and the minimum contents of local sanitary codes. It is illegal to discharge raw sewage directly to the surface waters of the state (unless the discharge is part of an NPDES permit with a combined or sanitary sewer overflow control plan). The TMDL does not change state or local oversight of septic systems or water discharge rules.

  • No. The TMDL does not contain any new requirements on agricultural operations without an NPDES permit. EGLE and the Michigan Department of Agriculture and Rural Development will continue to promote the Michigan Agriculture Environmental Assurance Program (MAEAP) throughout the state. In TMDL areas, EGLE requests that farmers and local agencies work together to voluntarily address pollution issues. If the issue is causing or contributing to a water quality impairment, EGLE will address the issue consistent with state laws and regulations. The TMDL provides links to funding opportunities that may be available to assist farmers with implementing voluntary Best Management Practices.

  • The permit requirements are generally the same across all concentration-based E. coli TMDLs. Permit requirements may change as part of the regular permit reissuance process, but they must remain consistent with the TMDLs according to state and federal regulations.

  • No. Michigan’s Rule 1062 of the Part 4, WQS (Part 4 Rules), promulgated pursuant to Part 31, Water Resources Protection, of the Natural Resources and Environmental Protection Act, 1994 PA 451, as amended, requires WWTPs to use fecal coliform in place of E. coli. There is an option for the WWTP to request an alternate parameter with EGLE approval. The TMDL does not change this, thus WWTP effluent monitoring should not be directly affected by the statewide E. coli TMDL.

  • This will depend on what type of permit you have and if you have sources of E. coli. Permit requirements are evaluated at each reissuance and must be consistent with an approved TMDL. As a starting point, EGLE recommends that permittees read their current permit in MiEnviro (start by doing a search for the keyword “TMDL” and “impaired waters”) or talk to your local NPDES district compliance staff.

  • A TMDL cannot be implemented in a permit until approved by the USEPA. After approval, EGLE will evaluate permits or certificates of coverage when permits are reissued and new requirements may be added, if warranted. The statewide E. coli TMDL was approved by the USEPA on July 29, 2019. The 2018 addendum to the TMDL was approved on October 1, 2019.

  • In general, no. Apart from the Rouge River, older E. coli TMDLs will remain in place. EGLE revoked the 2007 Rouge River E. coli TMDL and reissued it as part of the statewide E. coli TMDL.