Fitchburg, WI Environmental Rules: Stormwater Management (2026)

Fitchburg City Code § 30-23 requires a stormwater control permit under § 30-26 for any development after August 22, 2001 that cumulatively adds 20,000 square feet of impervious surface; any development needing a subdivision plat or certified survey map; redevelopment as defined in § 30-20 (construction or alteration disturbing more than 4,000 square feet on a predominantly commercial, industrial, institutional or multifamily site); or other land activity the city engineer determines could significantly increase downstream runoff, flooding, erosion or pollution. Once a permit is triggered, § 30-28's performance standards require, among other things, sediment control that reduces total suspended solids leaving the site by 80 percent for new development (or retains particles greater than five microns during a one-year, 24-hour storm); runoff rate control holding post-development peak flows at or below pre-development rates for the one-year, two-year, ten-year and 100-year, 24-hour storm events; and, under § 30-28(b)(6)a, infiltration practices designed so post-development infiltration volume equals at least 90 percent of the pre-development infiltration volume based on average annual rainfall.

Section 30-28(b)(6)e bars infiltration systems entirely in defined high-risk areas, including within 1,000 feet up-gradient of direct groundwater conduits and within 400 feet of a community water system well. Applicants submit plans to the city engineer under § 30-26, with a 15-business-day review, a required maintenance agreement recorded with the county register of deeds for privately owned facilities, and annual maintenance reporting under § 40-896. Variances from the numeric standards require the city engineer, after consulting the county conservationist, to find genuine unnecessary hardship under § 30-31(b).