Rockford, IL Environmental Rules: Stormwater Management (2026)

Any development in Rockford must get a stormwater management permit from the city before construction (Sec. 109-100). Detention (site runoff storage) is triggered for most residential development of two or more units on a half-acre-plus site, multifamily buildings over two units on a half acre or more, non-residential development or redevelopment of a half acre or more, aggregate road development over one acre in city rights-of-way, and parking lot or private road repairs that add impervious surface or raise peak flows (Sec. 109-20(b)). Absent an applicable watershed plan, the detention facility must hold enough storage that the post-development release rate has less than a 1% annual chance of exceeding 0.2 cfs per acre of development (Sec. 109-23(b)). Violations are fined up to $750 per violation per day (Sec. 109-208).