5 county-level rules, plus city-specific rules for 1 city in Johnson County, Iowa.
Verified from official government sources
Disturbing one acre or more in Johnson County triggers Iowa DNR's NPDES construction stormwater permit. Iowa City, Coralville, and North Liberty add local MS4 detention rules on top.
Sites disturbing one acre or more need erosion and sediment controls under Iowa DNR's construction stormwater permit and its SWPPP. Silt fence and quick stabilization keep soil out of the Iowa River and Clear Creek.
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.
Iowa 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 ...
Johnson County, Iowa City, and Coralville enforce NFIP floodplain rules along the Iowa River and Clear Creek, and Iowa DNR permits work in the floodway. The 2008 flood reshaped local standards.
Johnson County and its cities require permits for significant grading and bar redirecting runoff onto neighbors. Earthwork in a mapped floodplain also needs an Iowa DNR flood plain permit.
1 cities in Johnson County have their own environmental rules rules. Each link goes to that city's dedicated page with code citations.
See every category we cover for Johnson County — parking, noise, fences, fires, animals, pools, and more.
Johnson County Ordinance Hub →