Buying Land in Plymouth County, Iowa

Zoning and subdivision: one office, a 2023 ordinance update, and the Schedule F farm test

Plymouth County Planning & Zoning, based at the Courthouse Annex (215 4th Ave SE, Le Mars), enforces the county's zoning ordinance, handles rezoning, variance, and conditional-use-permit requests, and manages all major and minor subdivision applications, with the Planning and Zoning Commission, Board of Adjustment, and Board of Supervisors serving as the county's decision-makers on those requests depending on the type of application. Reach the office at (712) 546-7516 or zoning@plymouthcountyiowa.gov. The current ordinance was most recently updated October 24, 2023, itself amending prior versions dating back to 1988, with intermediate updates in 1995 and 2017 -- a longer, more incremental drafting history than a county that adopted zoning once and left it largely unchanged.

Like every Iowa county that has adopted zoning, Plymouth County's ordinance can't restrict genuine agricultural use under the Chapter 335 farm exemption. What's specific here is the ordinance's practical test for that exemption: the Zoning Administrator determines whether a use qualifies as a farming operation, but the ordinance also states that any use for which the operator attests to filing a Schedule F as part of a federal income tax return is presumed to be a farm and therefore exempt. If you're planning a use that sits near the line between agricultural and non-agricultural (a hobby farm, an ag-tourism operation, a small livestock operation not filing Schedule F), don't assume the exemption applies automatically -- confirm the Administrator's determination in writing before you build or subdivide around that assumption.

Wells and septic: a County Sanitarian, flat $100 fees, and a note on shallow rural wells

Plymouth County's Sanitarian/Environmental Health office administers both well and septic permitting under Iowa Code Chapter 69 (567 IAC 455B). Both a well permit and a septic system permit run a flat $100 fee, each valid for one year, and a septic installation requires a site analysis to determine leach-line location and sizing before work begins. Contractors are asked to notify the Sanitarian 24 hours ahead of any inspection or system replacement. One specific caution the county's own materials flag: rural well users, especially those with a well in a pit or shallower than 100 feet, should test their water after heavy spring runoff, when shallow or pit wells are more vulnerable to contamination.

The Floyd River: a near-record 2024 crest, not a one-time event

The Floyd River runs through Plymouth County on its way to Sioux City, and it has a documented history of major flooding -- including disastrous events in Sioux City in 1892 and 1953. The most recent, and most locally consequential, event came on June 22, 2024, when the river crested at 26.3 feet in Le Mars, just a tenth of a foot short of the all-time record of 26.4 feet. That crest closed Highway 3 west, Highway 75 north, Highway 60, and Business Highway 75 south, washed out a bridge over the river on County Road 44 near Merrill, submerged most of Le Mars's airport taxiway, and forced evacuation of campers at Willow Creek Campground to the Plymouth County fairgrounds.

For a buyer, the takeaway is that Floyd River flooding in Plymouth County is a documented, recurring, and severe risk rather than a remote possibility -- a river that came within a tenth of a foot of its all-time record within the last two years is not a river to evaluate on distance-from-bank alone. Pull the current FEMA Flood Insurance Rate Map for any parcel near the Floyd River, and confirm floodplain development-permit requirements with Plymouth County Planning & Zoning before treating a parcel's flood risk as settled.

A top hog- and cattle-producing county, governed mostly by state rules

Plymouth County is a genuinely significant part of Iowa's livestock economy: it's among the state's top counties for hog inventory (grouped with Sioux, Lyon, Washington, and Hardin counties), among the top counties for cattle sold for slaughter, and its pork-industry value-added contribution is estimated above $300 million. In February 2022, the Board of Supervisors passed a resolution asking the Iowa Legislature to revisit the 2002 law governing hog-confinement siting and oversight -- Iowa's Master Matrix system -- reflecting real, ongoing local concern about how that state framework handles confinement approvals here.

For a buyer, the practical point is that this regulatory framework operates almost entirely at the state level: separation-distance requirements for confinement feeding operations (from sinkholes, other confinements, and protected waters, among other criteria) come from Iowa DNR's statewide Animal Feeding Operations rules (567 IAC Chapter 65), not a Plymouth County ordinance layered on top. Iowa DNR's AFO Siting Atlas is the tool used to check floodplain status and other siting criteria for a specific location. We found no evidence of a Plymouth-County-specific setback or siting rule stricter than the state standard; if that changes, confirm current status directly with the county.