Environmental Rules in McLean County, IL (2026)
5 rules for unincorporated McLean County, Illinois.
Verified from official government sources
Stormwater Management
Unincorporated McLean County requires stormwater and erosion control measures on any subdivision needing public improvements, sized to hold sediment on-site through a five-year-frequency storm and coordinated with the developer's state NPDES permit.
McLean County Stormwater Control Standards
Some RestrictionsMcLean County Code § 317-39
All control measures required under this article shall conform to the design criteria, standards, and specifications provided in the Manual, now in effect or as hereafter amended. All control measures installed shall be sufficient to prevent sediment from leaving the permit site during a five-year-frequency storm event. The County Engineer may require additional control measures pursuant to the...
Erosion Control
McLean County's zoning construction-permit rule forces erosion and sediment control on any building site in the unincorporated county disturbing over 5,000 square feet, with fixed 14-day and 21-day deadlines for stabilizing bare ground.
McLean County Construction Erosion Control Rule
Some RestrictionsMcLean County Code § 350-19B
Erosion and sediment control. Erosion is the process whereby soil or earth is moved by rainfall, flowing water, wind or wave action. Erosion and sediment control measures shall be installed at the time of construction and maintained during both the construction season and any construction shutdown periods where more than 5,000 square feet of land are disturbed or by the time of the stake-out in...
Flood Zones
No one may develop in a McLean County floodplain without a development permit from the Director of Building and Zoning, and violators face a $50-$750 fine per day plus a recorded notice of violation on the property's title.
McLean County Floodplain Development Permit Rule
Significant RestrictionsMcLean County Code § 350-41E
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 Director of Building and Zoning. The Director of Building and Zoning shall not issue a development permit if the proposed development does not meet the requirements of this section.
Boat Dock Permits
A boat dock built in the McLean County floodplain qualifies as a minor development activity without a full development permit only if it meets the ten conditions of IDNR/OWR Statewide Permit Number 5 spelled out in Zoning Code Section 350-41F(1)(d), including a 50-foot maximum extension and 10-foot width cap.
McLean County Minor Boat Dock Floodplain Rules
Some RestrictionsMcLean County, IL Code of Ordinances § 350-41.F(1)(d)
Minor boat docks meeting the following conditions of IDNR/OWR Statewide Permit Number 5: The boat dock must not extend more than 50 feet into a waterway and no more than 1/4 of the width of the waterway and shall not extend beyond the navigational limits established by the IDNR and Corps of Engineers. The width of the boat dock shall not be more than 10 feet. For L-shaped or T-shaped docks, the...
Flood Elevation Requirements
New buildings in McLean County's floodplain must have their lowest floor, including any basement, built at or above the flood protection elevation, defined by Zoning Code Section 350-41 as the base flood elevation plus one full foot of freeboard, before the County will issue a development permit.
McLean County Base Flood Elevation Freeboard
Significant RestrictionsMcLean County, IL Code of Ordinances § 350-41.B, § 350-41.G(2)(a)
The elevation of the base flood plus one foot of freeboard at any given location in the floodplain. ... The building may be constructed on permanent land fill in accordance with the following: The lowest floor (including basement) shall be at or above the flood protection elevation; The fill shall be placed in layers no greater than six inches before compaction and should extend at least 10 fee...
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