Michigan Stormwater Management (2026)

Key Facts

Permitting agency: EGLE Water Resources
Construction trigger: 1+ acres disturbed
Civil penalty: Up to $25,000/day
Statute: MCL 324.3103

Full Breakdown

MCL 324.3103 and 324.3106 give EGLE authority to issue NPDES stormwater discharge permits for municipal separate storm sewer systems (MS4s), construction sites disturbing one acre or more, and industrial activities. Permittees must implement six minimum control measures, including post-construction runoff controls. Local stormwater ordinances must meet or exceed state standards but cannot authorize discharges prohibited by EGLE.

Violations & Penalties

Violations carry civil penalties up to $25,000 per day under MCL 324.3115 plus potential criminal liability for knowing discharges.

Frequently Asked Questions

Do I need a state permit for a small backyard project?

Projects disturbing less than one acre and not part of a larger common plan are exempt from NPDES coverage, though local soil-erosion permits may still apply.

Who enforces stormwater rules locally?

EGLE has primary authority, but counties and MS4 permittees enforce delegated provisions. Citizens may also bring suit under Part 17 of NREPA for unpermitted discharges.

Michigan NPDES Stormwater Permitting Under Part 31

Key Facts

Full Breakdown

Violations & Penalties

Frequently Asked Questions

Sources

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