Iowa Code §459.310 — Master Matrix CAFO Siting Scorecard (IA)
Tracked preemption from the Iowa overlay bundle.
Overview
← All state preemptionsIowa overlay roll-upIowa zoning wikiIowa building codesFederal overlaysGlossaryFederal-conflict: Yes
Effective
2002-07-01
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 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)Iowa Code Ch. 461A + 571 IAC 13 — Sovereign Lands Construction Permits
Trigger predicate
When this evaluates true for a parcel, the law's preempted fields take precedence over base zoning.
AND
project.is_confinement_animal_feeding_operation==Truecounty.has_adopted_construction_evaluation_resolution==True
Preempted fields
2 fields on the base district schema are rewritten when the trigger fires.
| Field | Op | Value | Note |
|---|---|---|---|
review_type | require | DNR_master_matrix_scoring_plus_county_recommendation | Confinement feeding operation structures requiring a construction permit (generally ≥1,000 animal units) must score on the Master Matrix — a DNR-designed objective scoring system evaluating siting and orientation against separation distances required under §§459.202 and 459.204. Counties that adopt an annual construction-evaluation resolution may review applications, score the matrix, and submit a recommendation to DNR; the final permit decision rests with DNR. |
county_zoning.cafo_siting_authority | cap_at | ch_459_field_preemption | Iowa Code ch. 459 (Animal Agriculture Compliance Act) occupies the field for CAFO siting — counties may NOT impose CAFO-specific zoning, setback, or siting ordinances beyond the master matrix participation channel and the §335.2 ag-exemption umbrella. |
Citation
Authority source
Iowa Code ch. 459 (Animal Agriculture Compliance Act); §459.305 (master matrix establishment); §459.310 (master matrix scoring and county evaluation); 567 IAC ch. 65 (Animal Feeding Operations).
§ Iowa Code §§459.305, 459.310; 567 IAC 65
Research notes
Field-preemption overlay. Federal conflict check flagged because the largest CAFOs (≥2,500 hogs / equivalent thresholds) are also EPA-regulated Concentrated AFOs under the federal Clean Water Act. The master matrix does NOT apply to open feedlots (separately regulated under ch. 459A). Counties' role is advisory — DNR makes the final siting decision based on matrix score and statutory separation distances. This statute is the principal mechanism by which Iowa has limited county zoning authority over agricultural production, complementing the §335.2 farm exemption.