Milton, WI Environmental Rules: Stormwater Management (2026)

Milton's post-construction stormwater ordinance, adopted under the state authority in Wis. 234 for cities, applies to any post-construction site with five or more acres of land-disturbing activity, or one acre or more for development after March 10, 2003, per Sec. 10-414. A responsible party must obtain a permit from the director of public works or city engineer before starting work, supported by a stormwater management plan, a maintenance agreement and a nonrefundable fee under Sec. 10-418. The performance standards in Sec. 10-417 require best management practices designed to reduce total suspended solids load by 80 percent for new development compared to no controls, and by 40 percent for redevelopment and most in-fill projects, based on average annual rainfall; no one is required to exceed those percentages.

The same section sets infiltration targets ranging from 90 percent of pre-development infiltration volume for residential development down to 60 percent for commercial, industrial and institutional sites, and establishes protective buffer areas of 50 to 75 feet along lakes, streams and sensitive wetlands where impervious surface is kept out to the maximum extent practicable. The plan required under Sec. 10-419 must show pre- and post-development site maps, hydrology computations, an installation schedule and a maintenance plan certified by a licensed professional engineer, and the maintenance agreement under Sec.

10-420 is recorded with the Rock County register of deeds so it binds future owners. The director of public works or city engineer must act on a complete application within 30 business days under Sec. 10-418(c), and appeals of any decision go to the board of zoning appeals under Sec. 10-424, which was amended as recently as November 18, 2025.