Iowa Code Chapter 335 — County Zoning Enabling Act + §335.2 Agricultural Exemption (IA)
Tracked preemption from the Iowa overlay bundle.
Overview
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Effective
1947-01-01
Sunset
—
Authority
state
Scope
state:IA
Other Iowa preemptions
Iowa SF 592 (2025) — Statewide Accessory Dwelling Unit By-Right MandateIowa Code §414.1(2) — Short-Term Rental Preemption (Residential Use Classification)Iowa Code §459.310 — Master Matrix CAFO Siting ScorecardIowa Code Ch. 161D — Loess Hills Development and Conservation Authority + AllianceIowa Code §414.28 / §335.30 — Manufactured Home Zoning Parity MandateIowa Code Ch. 303 — State Historical Society / SHPO Review + Local Historic Preservation CommissionsIowa Code §352.6 — Agricultural Area Designation + Right-to-Farm Nuisance ProtectionIowa Code Ch. 455B + 567 IAC 71 — Floodplain Development Approval (DNR Flood Plain Program)
Trigger predicate
When this evaluates true for a parcel, the law's preempted fields take precedence over base zoning.
AND
parcel.in_unincorporated_county_territory==Truecounty.has_adopted_zoning_ordinance==True
Preempted fields
3 fields on the base district schema are rewritten when the trigger fires.
| Field | Op | Value | Note |
|---|---|---|---|
county_zoning.scope | cap_at | unincorporated_territory_only | County zoning applies only to unincorporated territory (§335.1); inside city limits, municipal zoning prevails. |
county_zoning.farmland_and_farm_buildings | waive | — | County zoning ordinances SHALL NOT apply to land, farm houses, farm barns, farm outbuildings, or other buildings/structures primarily adapted for agricultural use, while so used (§335.2). Floodplain exception preserved — counties may zone in/on floodplains regardless of ag character. Post-2020 amendments (HF 2403 / SF 2195) bar counties from requiring application/approval/fee for the exemption to attach, and extend the exemption to parcels enrolled in soil/water conservation programs. |
county_zoning.agritourism | permit_with_carveouts | section_335_2A | Agricultural-experience (agritourism) carveout at §335.2A — counties may regulate certain non-farm-production agritourism uses notwithstanding the §335.2 farm-exemption umbrella. |
Citation
Authority source
Iowa Code ch. 335 (County Zoning); §335.2 (Farms exempt); §335.2A (Agricultural experience); §335.27 (Agricultural land preservation ordinance). Iowa Const. Art. III §39A (County Home Rule) is the constitutional anchor.
§ §§335.1, 335.2, 335.2A, 335.27, 335.30
Research notes
The famous Iowa carveout. Lang v. Linn County Board of Adjustment, 829 N.W.2d 1 (Iowa 2013), is the controlling 'sideline ag' doctrine: counties may deny the exemption where 'agricultural activities are basically a sideline designed to obtain an agricultural zoning exemption for the owners' residence.' Counties retain authority to investigate whether a use is genuinely agricultural ('primarily adapted… while so used'). City-level analog (§414.1A) is materially narrower. This is the central zoning-enforcement tension at metro-fringe annexation areas (Des Moines, Cedar Rapids, Iowa City, Quad Cities, Waterloo/Cedar Falls).