Ashwaubenon, WI Environmental Rules: Stormwater Management (2026)

Section 5-9-771 is the Village's post-construction companion to its construction-site erosion ordinance, adopted under the same village authority in Wis. Stat. 354 and administered by the director of public works. It applies to essentially every post-construction site in Ashwaubenon unless the project is a one- or two-family home outside a larger development plan disturbing less than an acre, a non-point agricultural or silviculture discharge, or a mill-and-crush operation, though the director can still pull an otherwise exempt site back into the ordinance if its runoff threatens drainage capacity, causes channel erosion or endangers property.

For sites that need a permit, the storm water management plan must control peak discharge so the post-development rate does not exceed the pre-development rate for the 1-year, 2-year, 10-year and 100-year, 24-hour design storms, and must meet infiltration standards that vary by land use: at least 90 percent of pre-development infiltration volume for institutional, park, cemetery and low-density residential sites, 75 percent for multi-family, industrial, institutional and office park sites, and 60 percent for commercial strip malls, shopping centers and downtowns. A maintenance agreement recorded with the Brown County Register of Deeds binds future owners to the upkeep schedule set out in the plan, and the director may require a financial guarantee sized to the estimated construction and maintenance cost.

Applicants seeking an exemption or a permit for a site under 20,000 square feet of impervious surface disturbance can ask the director for alternative, less demanding submittal requirements. The ordinance is enforced the same way as its erosion control counterpart, through stop-work orders, permit revocation, cease and desist orders and injunctions.