Environmental Rules in Johnson County, IA (2026)
5 county-level rules, plus city-specific rules for 1 city in Johnson County, Iowa.
Verified from official government sources
Stormwater Management
Unincorporated Johnson County requires an adequate stormwater management plan before approving most subdivisions, site plans, and conditional uses. Plats for commercial, industrial, or multi-lot residential subdivisions cannot be approved, and no certificate of occupancy issued, until stormwater infrastructure is built and certified.
Johnson County Stormwater Management Rules
Some RestrictionsJohnson County UDO § 8:3.6(A)(1),(6)
The Board shall not approve any preliminary, combined, or final plat for any commercial or industrial subdivision; a residential subdivision with two (2) or more buildable lots; or a request to change the zoning designation of a property to RE-Renewable Energy, unless it includes a stormwater management plan that is adequate to serve the proposed development... 6. Waiver of Requirements. The Zo...
Erosion Control
Johnson County requires an approved soil erosion and sediment control plan before the Zoning Administrator issues a building permit for a new dwelling, a dwelling addition of 1,000 square feet or more, or any project disturbing more than a quarter acre. The same plan requirement applies to preliminary plats, site plans, grading permits and demolition permits in the unincorporated county.
Johnson County Erosion & Sediment Control Rules
Some RestrictionsJohnson County UDO § 8:3.7(A)(3)
The Zoning Administrator shall not issue a building permit which meets one or more of the following, unless it includes a soil erosion and sediment control plan that is adequate to serve the proposed development: A new dwelling. Dwelling addition with a footprint of one thousand (1,000) square feet of greater. The proposed total ground disturbance is greater than one quarter (1/4) acre. A Soil ...
Coastal Development
Coastal rules do not apply in Johnson County. This is landlocked eastern Iowa. Work near water here follows Iowa DNR floodway permits, local floodplain ordinances, and Army Corps rules around Coralville Lake.
Johnson County Waterway & Floodway Rules
Few RestrictionsIowa Code § 455B.275(1)
A person shall not permit, erect, use, or maintain a structure, dam, obstruction, deposit, or excavation in or on a floodway or floodplains, which will adversely affect the efficiency of or unduly restrict the capacity of the floodway, or adversely affect the control, development, protection, allocation, or utilization of the water resources of the state, and the same are declared to be public ...
Flood Zones
Any development in a mapped floodplain in unincorporated Johnson County, including placing a factory-built home, needs a Floodplain Development Permit from the Zoning Administrator first. Fill placement is capped at 5 feet deep and can't go within 25 feet of the floodway.
Johnson County Floodplain Development Permits
Significant RestrictionsJohnson County UDO § 8:4.6(B)(1), (B)(3)
B. Floodplain Development Permit. 1. Permit Required. A Floodplain Development Permit issued by the Administrator shall be secured prior to any floodplain development, including the placement of factory-built homes. "Development" means any man-made change to improved and unimproved real estate, including but not limited to buildings or other structures, mining, dredging, filling, grading, pavin...
Flood Elevation Requirements
New and substantially improved residential structures in Johnson County's Floodway Fringe Overlay District must have their lowest floor, including any basement, elevated at least one foot above the base flood elevation. Non-residential structures can meet the same one-foot freeboard either by elevation or by certified floodproofing to that level.
Johnson County Flood Elevation & Freeboard Rules
Some RestrictionsJohnson County UDO § 8:4.8(B)(2)
All new or substantially improved residential structures shall have the lowest floor, including basement, elevated a minimum of one (1) foot above the base flood elevation. Construction shall be upon compacted fill which shall, at all points, be no lower than one (1.0) feet above the base flood elevation and extend at such elevation at least eighteen (18) feet beyond the limits of any structure...
Environmental Rules by City in Johnson County
1 cities in Johnson County have their own environmental rules rules. Each link goes to that city's dedicated page with code citations.
All Johnson County ordinances
See every category we cover for Johnson County: parking, noise, fences, fires, animals, pools, and more.
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