Olmsted County, MN Environmental Rules: Stormwater Management (2026)
Key Facts
- Governs
- County MS4 storm drainage system, all of Olmsted County
- Enforcing agency
- Public Works, Environmental Resources and Planning Depts.
- Core rule
- No discharge but storm water into storm drains/watercourses
- Construction trigger
- NPDES permit needed at 1+ acre land disturbance
- Dye testing notice
- 3 days written notice to county required
- Criminal penalty
- Up to $1,000 fine and/or 90 days jail per day
- Appeals
- Governed by Chapter 4000 enforcement/appeals ordinance
Summary
Olmsted County bans dumping anything but storm water into its MS4 storm drainage system and watercourses under Chapter 3800. The Public Works, Environmental Resources and Planning Departments enforce it, and illicit connections or discharges can draw a notice of violation, remediation costs, or criminal charges.
No person shall discharge or cause to be discharged into the County storm drainage system or watercourses any materials, including but not limited to pollutants or waters containing any pollutants that cause or contribute to a violation of applicable water quality standards, other than storm water. ... Any person violating the provisions of this ordinance for which no civil notice of violation has been issued shall be guilty of a misdemeanor criminal offense punishable by a fine of up to $1000 or a jail sentence of up to 90 days or both. Each day that violation is committed or permitted to exist shall constitute a separate offense.
Full Breakdown
Chapter 3800, the Illicit Stormwater Discharge Ordinance, applies to all water entering the county's separate storm sewer system (MS4) from developed and undeveloped land in the urbanized area of Olmsted County, per Section III. " A short, specific exemption list covers things like municipal water line flushing, landscape irrigation, diverted stream flows, rising or infiltrating ground water, foundation and footing drains that are not active dewatering systems, air conditioning condensation, non-commercial vehicle washing, dechlorinated swimming pool water under 1 PPM chlorine, and firefighting water. Dye testing is allowed only with written notice to the county at least three days ahead.
Illicit connections, including pipes conveying sewage into the MS4, are prohibited outright and the prohibition reaches connections made in the past regardless of whether they were legal when installed. 20. Enforcement runs through the Public Works Department, which can issue a written notice of violation ordering monitoring, elimination of the illicit connection or discharge, a stop-work/cease-and-desist directive, remediation of the property, payment of a fine covering administrative and remediation costs, and installation of best management practices. If a violator misses the deadline in the notice, the county or its contractor can do the remediation work and bill the violator for it. Appeals of a civil notice of violation run through the county's Chapter 4000 Administrative Enforcement and Appeals Procedure Ordinance.
Violations & Fines
A violation for which no civil notice was issued is a misdemeanor punishable by a fine up to $1,000, up to 90 days in jail, or both, with each day of continuing violation a separate offense under Section XVII. The county can also treat a violation as a public nuisance, summarily abate or restore the site at the violator's expense, seek an injunction, and recover attorney's fees, court costs, and sampling and monitoring expenses on top of any fine.
Frequently Asked Questions
Can I wash my car and let the water run into the storm drain?
Does a construction site need a stormwater permit in Olmsted County?
What happens if my old pipe connection dumps sewage into the storm drain?
Who enforces Olmsted County's stormwater rules?
Sources & Official References
Other rules in Olmsted County
Compare Olmsted County to another location·View the Minnesota environmental rules overview
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