Environmental Rules in Polk County, IA (2026)
5 county-level rules, plus city-specific rules for 1 city in Polk County, Iowa.
Verified from official government sources
Stormwater Management
Unincorporated Polk County requires stormwater detention facilities on developments that cannot directly discharge runoff, under the county Zoning Ordinance's Stormwater Runoff standards. Public Works decides detention need at plat, site-plan or grading-permit review, and any required facility must be designed by a professional engineer licensed in Iowa to meet four numeric volume-control standards.
Stormwater Detention Rules in Polk County, Iowa
Some RestrictionsPolk County Zoning Ordinance, Art. 8, Div. 1, §§ 5-6
Section 5. Stormwater Detention Required Developments not able to directly discharge all flows as indicated in Section 2 above shall provide for detention and design the facility as follows: (A) If stormwater detention is required, the developer or applicant shall construct stormwater detention facilities designed by a registered professional engineer in the State of Iowa and meeting the crit...
Erosion Control
Unincorporated Polk County requires a Grading Permit for land-disturbing work exceeding three feet of fill, five feet of excavation, or 5,000 square feet of grading or clearing. The Zoning Ordinance's erosion and sediment control division adopts Iowa DNR's construction erosion standards by reference and Public Works issues and enforces the permit.
Grading Permit & Erosion Control, Polk County
Some RestrictionsPolk County Zoning Ordinance, Art. 8, Div. 2, Sec. 2
Section 2. Applicability No person shall engage in land-disturbing activities that include fill in excess of three (3) feet, excavation exceeding five (5) feet or any grading or clearing activity that disturbs an area of five thousand (5,000) square feet within the unincorporated parts of Polk County unless they have received a Grading Permit. In addition, through the Iowa DNR, owners of certa...
Flood Zones
Building in a special flood hazard area of unincorporated Polk County requires a Floodplain Development Permit from the Zoning Administrator before any work starts. The county uses the FIRM maps dated February 1, 2019 to identify the 1% Annual Chance floodplain, and reserves the floodway itself as permanent open space with 100 percent flood protection.
Floodplain Development Permit Rules in Polk County
Significant RestrictionsPolk County Zoning Ordinance, Art. 7, Sec. 1(C), 1(H), 1(O)
The Flood Insurance Rate Maps (FIRMs), for Polk County and Incorporated Areas dated February 1, 2019, and later as revised, which were prepared as part of the Polk County Flood Insurance Study, shall be used to identify the special flood hazard areas. All areas shown thereon to be within the boundaries of the 1% Annual Chance (100-year) flood zone shall be considered as having significant flood...
Boat Dock Permits
Boat launching ramps, boat docks, piers and marinas are allowed in the floodway and floodway fringe of unincorporated Polk County, but only as a conditional use with added engineering standards, and only after a Floodplain Development Permit is issued by the Zoning Administrator. Boat or motor repair buildings and showrooms are specifically excluded.
Boat Dock and Ramp Permits in Polk County
Some RestrictionsPolk County Zoning Ordinance, Art. 7, Sec. 1(I)(3), 1(O)
(3) Uses Permitted Within Floodways and Floodway Fringes with Certain Additional Standards. The following uses shall be permitted in Floodway and Floodway Fringe Areas if all applicable requirements of this section are met. (a) Boat launching ramps, boat docks, piers, bridges and bridge approaches, marinas, and stormwater detention facilities. (b) Boat houses, boat storage buildings and operati...
Flood Elevation Requirements
New or substantially improved homes in the unincorporated Polk County floodplain must have the lowest floor at least one foot above the 1% Annual Chance base flood elevation, built on compacted fill extending 18 feet beyond the structure. Levees and flood walls must carry three feet of design freeboard on top of that same base flood elevation.
Base Flood Elevation Freeboard Rules in Polk County
Some RestrictionsPolk County Zoning Ordinance, Art. 7, Sec. 1(J)(1)(c), 1(J)(6), 1(Q)
All residential structures which are constructed or substantially improved after the date of adoption of this Ordinance shall have the lowest floor, including lowest level, elevated a minimum of one (1) foot above the 1% Annual Chance flood level. Construction shall be upon compacted fill which shall, at all points, be no lower than one (1) foot above the 1% Annual Chance flood level and extend...
Environmental Rules by City in Polk County
1 cities in Polk County have their own environmental rules rules. Each link goes to that city's dedicated page with code citations.
All Polk County ordinances
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