Environmental Rules in St. Clair County, IL (2026)
5 rules for unincorporated St. Clair County, Illinois.
Verified from official government sources
Stormwater Management
Unincorporated St. Clair County requires a Stormwater Management and Erosion Control Permit from the Building and Zoning Department before any new development or redevelopment that disturbs land. The threshold trips at 10,000 square feet of impervious surface or one acre of disturbed land, and violators face fines up to $1,000 per day.
Stormwater Rules in Unincorporated St. Clair County
Some RestrictionsSt. Clair County Stormwater Control Code Sec. 33-1-3; Sec. 33-7-3
This Code shall apply to all new development and redevelopment in the County as set forth herein: (A) Any new development or redevelopment that will include an area that will meet or exceed ten thousand (10,000) square feet of total impervious surface (i.e., streets, roof, patio or parking area or any combination thereof); or that involves one (1) acre or more of land... Any person who violates...
Erosion Control
Any new development or land-disturbing project in unincorporated St. Clair County that disturbs an acre or more, adds 10,000 square feet of impervious surface, moves more than 100 cubic yards of earth, or works within 25 feet of a stream or wetland needs a Stormwater Management and Erosion Control Permit from the Building and Zoning Department under Stormwater Control Code Sec. 33-1-3.
Erosion Control Rules in Unincorporated St. Clair County
Some RestrictionsSt. Clair County Stormwater Control Code Sec. 33-1-3
33-1-3 APPLICABILITY. This Code applies to all new development or redevelopment in the County... no person, firm or corporation... shall commence any development or redevelopment activities without first obtaining a Stormwater Management and Erosion Control Permit from the Building and Zoning Department. This Code shall apply to all new development and redevelopment in the County as set forth h...
Flood Zones
St. Clair County requires a floodplain development permit from the Zoning Director before any grading, filling, or construction begins in a mapped floodplain outside incorporated towns. Applicants must submit site plans, elevation data, and a Flood Insurance Rate Map excerpt; the Zoning Director reviews the site against the base flood elevation before approving work in the Special Flood Hazard Area.
Floodplain Development Permits in St. Clair County
Some RestrictionsSt. Clair County Floodplain Code § 13-1-5
13-1-5 DEVELOPMENT PERMIT. No person, firm, corporation, or governmental body not exempted by law shall commence any development in the floodplain without first obtaining a development permit from the Zoning Director. The Zoning Director shall not issue a development permit if the proposed development does not meet the requirements of this Code.
Boat Dock Permits
Building a boat dock in unincorporated St. Clair County requires a floodplain development permit from the Zoning Director before work starts, under Floodplain Code Sec. 13-1-5. A minor dock qualifies automatically if it meets Illinois DNR Office of Water Resources Statewide Permit No. 5 conditions per Sec. 13-1-6(A)(3). Docks and marinas sited in the county's C-R Conservation-Recreation zoning district additionally need a Special Use Permit.
Boat Dock Permits in St. Clair County, IL
Some RestrictionsSt. Clair County Floodplain Code Sec. 13-1-5 & 13-1-6(A)(3)
13-1-5 DEVELOPMENT PERMIT. No person, firm, corporation, or governmental body not exempted by law shall commence any development in the floodplain without first obtaining a development permit from the Zoning Director. The Zoning Director shall not issue a development permit if the proposed development does not meet the requirements of this Code. ... 13-1-6 PREVENTING INCREASED FLOOD HEIGHTS AND...
Flood Elevation Requirements
St. Clair County sets its flood protection elevation, the height a building must clear, at the base flood elevation plus two feet of freeboard. Every new floodplain building, substantially damaged repair, manufactured home, or travel trailer left in place over 180 days must have its lowest floor, and all mechanical and electrical equipment, built at or above that two-foot-freeboard elevation.
Base Flood Elevation Freeboard in St. Clair County
Some RestrictionsSt. Clair County Floodplain Code §§ 13-1-2, 13-1-7
"FLOOD PROTECTION ELEVATION" or "FPE" means the elevation of the base flood plus two (2) feet of freeboard at any given location in the floodplain. ... 13-1-7 PROTECTING BUILDINGS. In addition to the damage prevention requirements of Section 13-1-6, all buildings located in the floodplain shall be protected from flood damage below the flood protection elevation. ... the lowest floor and all ele...
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