Winnebago County, WI Environmental Rules: Stormwater Management (2026)
Key Facts
- Permit trigger (area)
- 4,000 sq ft of disturbance
- Permit trigger (volume)
- 400 cubic yards of soil
- Scope
- Unincorporated Winnebago County only
- Penalty
- $500–$1,000 per offense
- Administered by
- Planning & Zoning Department
Summary
Winnebago County requires an erosion-control permit for construction disturbing 4,000 square feet or more, or moving 400 cubic yards of soil, anywhere in the unincorporated county, separate from the town/county zoning district rules.
This ordinance applies to land-disturbing construction activity, new land development, and all land redevelopment activity located within the boundaries and jurisdiction of the unincorporated portion of Winnebago County... Those involving grading, removal of protective ground cover or vegetation, excavation, land filling or other activity affecting a surface area of 4,000 square feet or more; Those involving excavation or filling... affecting 400 cubic yards or more of soil, sand, or other excavation or fill material;
Full Breakdown
Chapter 23, Article 15 is the county's Construction Site Erosion Control and Stormwater Management Ordinance, adopted under Wis. Stat. § 59.693: a separate authority from the town-by-town § 59.69 zoning-adoption process that governs Ch. 23's regular zoning districts. It applies within the boundaries and jurisdiction of the unincorporated portion of Winnebago County, and even reaches land later annexed into a city or village unless that municipality enforces an equally strict rule. A permit is triggered once grading, clearing, excavation, or filling affects 4,000 square feet or more, or moves 400 cubic yards or more of soil or fill; roads, drives, or utility work over 100–125 feet also trigger it. The Planning & Zoning Department administers and enforces it.
Violations & Fines
Skipping the required erosion-control permit, or failing a stop-work order, is enforced with a forfeiture of $500 to $1,000 per offense plus court costs and prosecution costs, and every day of noncompliance is a separate violation.
Frequently Asked Questions
Do I need a stormwater/erosion permit to build a shed in unincorporated Winnebago County?
Does this ordinance apply inside Oshkosh or Neenah?
Sources & Official References
Other rules in Winnebago County
Compare Winnebago County to another location·View the Wisconsin environmental rules overview
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