Environmental Rules in DuPage County, IL (2026)
4 county-level rules, plus city-specific rules for 1 city in DuPage County, Illinois.
Verified from official government sources
Stormwater Management
DuPage County's Countywide Stormwater and Flood Plain Ordinance makes it unlawful to undertake development without first securing a stormwater management certification. In the regulatory flood plain, new or added usable space must sit at least one foot above the base flood elevation, floodproofed and certified by a professional engineer under Sec. 15-28.
DuPage County Stormwater Certification Rule
Significant RestrictionsDuPage County Code §§ 15-102(A), 15-28(A)
15-102: - PROHIBITED ACTS. A.It shall be unlawful for any person to undertake any development within the County or within a waiver community without first securing a stormwater management certification as required by this chapter or the applicable waiver community ordinance. 15-28: - BUILDING PROTECTION. A.Within the boundary of the regulatory flood plain, all usable space in new buildings, or ...
Erosion Control
Excavating or filling any tract of unincorporated land in DuPage County requires a Building Official permit and an engineer-stamped grading plan before work starts.
DuPage County Grading & Drainage Permit
Some Restrictions8-112.1
It shall be unlawful to change the occupancy of, construct, add to, alter, relocate, remove or demolish a building or structure, or excavate and or fill any tract of land ... without first filing with the Building Official an application in writing and obtaining a formal permit.
Flood Zones
No development activity in unincorporated DuPage County's flood plain may worsen upstream or downstream flooding, and the regulatory floodway is closed to all but a short list of approved uses. A stormwater management certification from the county is required before any work begins.
DuPage County Floodplain & Floodway Development Rules
Significant RestrictionsDuPage County Code §§ 15-81(A), 15-82(A), 15-102(A)
A.General Performance Standards.1.No development activity within the flood plain shall result in an adverse hydraulic impact to upstream or downstream properties. ... In the regulatory floodway, all of the requirements of article X shall apply to any proposed development, and only the following appropriate uses shall be considered for certifications:1.Flood control structures, dikes, dams and o...
Flood Elevation Requirements
Unincorporated DuPage County requires one foot of freeboard above the base flood elevation for any new construction in the regulatory flood plain. New or substantially improved homes must set their lowest floor at that flood protection elevation, with flood-vent openings sized to equalize water pressure underneath.
DuPage County Flood Elevation & Freeboard Rule
Some RestrictionsDuPage County Code §§ 15-80.H, 15-81.B.2
H.The flood protection elevation (FPE) is the BFE plus one (1) foot of freeboard. ... 2.New construction or substantial improvements of residential buildings within a SFHA shall have the lowest floor elevated to at least the FPE and that the fully enclosed areas below the lowest floor that are usable solely for parking of vehicles, building access or storage in an area other than a basement and...
Environmental Rules by City in DuPage County
1 cities in DuPage County have their own environmental rules rules. Each link goes to that city's dedicated page with code citations.
All DuPage County ordinances
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