Peoria County, IL Environmental Rules: Stormwater Management (2026)

Under UDO Sec. 13, before commencing any commercial, institutional, multifamily or industrial project with an area of more than one-half acre, or a project requiring subdivision approval by a unit of local government with an area of more than one-half acre, the landowner or representative must file an application for an Erosion, Sediment, and Stormwater Control Permit with the county's Planning and Zoning Department before construction begins. Under Sec. 1, the application must include an existing site conditions map at a scale of at least one inch equals one hundred feet, showing site and adjacent boundaries, lakes, streams, wetlands, channels, ditches and other watercourses, floodways and Zone A floodplain areas keyed to the FIRM panel number, all off-site drainage flowing onto or through the site, the location of stormwater management components, and site topography shown at two-foot contour intervals for slopes of six percent or less, five-foot intervals for slopes between six and fifteen percent, and ten- or twenty-foot intervals for slopes over fifteen percent.

A companion plan of final site conditions, drawn to the same scale, must also be submitted showing how the finished grading and drainage will function once the project is built. The permit requirement is separate from, and in addition to, any building permit or subdivision plat approval the same project may also need under Article 3's general development review procedures.