Sheboygan, WI Environmental Rules: Stormwater Management (2026)

Appendix E, the Post-Construction Stormwater Management Zoning Ordinance, was adopted under Wisconsin Statutes section 62.234 and names the Director of Public Works, or a designee, as the Administering Authority. It applies after final stabilization to a post-construction site that had five or more acres of land disturbance, to a post-development site that had one or more acres after March 10, 2003, and, under Section 4(1)(a)3, to a site with more than 1,000 square feet but less than one acre of disturbance, which needs a permit but only has to meet the peak discharge standard unless the authority requires more. Section 4(2) extends the ordinance to land in the City's extraterritorial zoning jurisdiction even when plat approval is not involved. Exempt sites include a redevelopment with no increase in exposed parking lots or roads, a site with less than ten percent connected imperviousness where all parking lots and rooftops total under one acre, agricultural and silviculture discharges, and underground utility construction.

The performance standards in Section 7 set numbers. For new development the plan must reduce the total suspended solids load by 80 percent to the maximum extent practicable; for redevelopment the figure is 40 percent. Peak runoff must be held at or below predevelopment rates for the two-year, 24-hour design storm, and the site must at a minimum detain the ten-year, 24-hour design storm released at the two-year predevelopment rate. The Administering Authority can require retention up to the 100-year storm because of downstream threats, and the grading plan must pass the 100-year storm around or through the development without harm to life or property. Residential developments must infiltrate runoff so that post-development infiltration volume is at least 90 percent of pre-development volume, using no more than one percent of the project site, or infiltrate 25 percent of the post-development runoff from the two-year, 24-hour design storm.

Under Section 8, no responsible party may undertake land disturbing construction activity without a post-construction runoff permit. The application carries the plan, a maintenance agreement and a non-refundable administration fee, and the authority answers within 30 business days of a complete application, or ten business days after added information arrives. Fees are set by Common Council resolution under Section 12. The text reflects the Municode edition current to its 2023 update.