Blog · October 14, 2026 · Iowa
Clear Lake Flood Zone Map, Iowa: a practical guide
Flood zones are set by FEMA, and checking one near Mason City takes a few minutes.
Main page: Cerro Gordo County, IA GIS & Parcel Viewer (official map link, county facts and neighboring maps).
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Ahead of any purchase around Rockwell, check the Clear Lake flood zone map: a mapped flood zone changes insurance, building rules and resale. What this Clear Lake guide covers: finding the address on FEMA's map, reading the zone codes, and pairing it with the Cerro Gordo County Beacon site.
Where the Clear Lake flood zone map lives
If you'd rather pan and zoom, try the National Flood Hazard Layer viewer, which lets you click a spot and read its zone. Rural land near Ventura with no street number can still be found: pan from the closest town then click the parcel area.
Where the parcel data lives
Begin with the Cerro Gordo County Beacon site; it covers each assessed parcel around Plymouth and Ventura. If you're looking near Swaledale, enter a street address, an owner's name or a parcel number, and the viewer zooms to the match. For acreage around Mason City, write down the parcel ID before closing the panel; each clerk in the county asks for it first.
Questions to ask before you buy
Ask the listing agent about past flood claims for the house near Rockwell; an insurance quote early avoids surprises.
Water near Mason City
Small streams around Swaledale aren't always studied in detail, so ask neighbors about past flooding. Wetlands near Plymouth can limit building even outside a flood zone; check the National Wetlands Inventory mapper for a first look.
City limits and county records
Clear Lake lies within Cerro Gordo County, Iowa, and the county assessor maps its lots. If the land is near Swaledale, City or town hall handles things like zoning, permits and utilities within town limits, while the county keeps the tax map. Land beyond the city limits toward Mason City usually follows county rules instead.
Getting your bearings
Mason City serves as the county seat, which is where the courthouse records live. Other places on the map include Ventura, Swaledale, and Thornton. About 42,406 people call Cerro Gordo County home (Census estimate, 2023) across about 568 square miles. The county was formed in 1851, and some chains of title near Ventura are long.
Next door to Cerro Gordo County
Cerro Gordo County touches Butler County, Floyd County, Franklin County, Hancock County, and Mitchell County, all with their own assessor records. A tract near the line by Thornton can be split across two assessors' files, so open the neighboring map as well. For a home near Rockwell, the Platbookmapper state page lists every neighboring county map for Iowa.
Reading A, AE and X
If the land is near Thornton, any A or V zone are Special Flood Hazard Areas, land with a 1-percent chance of flooding in any year. Closer to Ventura, a shaded X area is moderate risk, roughly the 100- to 500-year range; unshaded X means minimal mapped risk.
Which office to call
Recorded documents for a parcel near Plymouth come from the County Recorder, usually searchable by name or document number. Questions about what you can build around Rockwell go to planning, building or health offices, and the answer depends on jurisdiction.
Legal descriptions in Iowa
Iowa is laid out under the Public Land Survey System, so deeds around Mason City reference sections and townships. Each section is nominally a mile square, about 640 acres, and a township holds 36 of them, though corrections make some sections near Ventura odd-sized. Keep the legal description for land near Mason City for any title or survey request.
Matching the zone to the lot lines
FEMA's map shows zones but not ownership, so open the Cerro Gordo County Beacon site next to see exactly which lot near Mason City you're looking at.
What the map can't tell you
The acreage figure is an estimate; just a licensed surveyor sets the real corners on land around Rockwell. With a lot near Mason City, owner names and values update on a schedule, so a deed recorded last month might lag behind.
Lenders and permits
If a building sits in a Special Flood Hazard Area and a federally regulated lender is involved, flood insurance is generally required where the community participates in the National Flood Insurance Program, and that holds around Swaledale too. Building or adding on near Plymouth in a mapped zone usually means extra permit review; ask the local floodplain administrator before you plan.
Frequently asked
Can I challenge a flood zone near Swaledale?
FEMA's LOMA process is the usual route when a building near Plymouth sits above the base flood elevation; a surveyor's elevation data supports it.
Does the county parcel map show flood zones in Clear Lake?
It depends, but a flood layer may appear in the Cerro Gordo County Beacon site layer list, though it can lag behind FEMA's current panels.
What is a base flood elevation in Clear Lake?
Good question; the BFE is printed in AE zones on FEMA's map; surveyors near Ventura use it often.
Is AE a high-risk flood zone near Mason City?
For most people, an AE zone has a 1% annual chance of flooding and a base flood elevation, so builders near Mason City design to that elevation.
How do I save a parcel from the viewer around Plymouth?
Use the print button or a screenshot, and it's worth keeping the parcel ID visible for land near Plymouth.
Open the official Cerro Gordo County, IA parcel map See it in the Platbookmapper directory
Not a survey. County GIS and tax parcel maps are assessment and planning layers. They are not a substitute for a recorded plat, deed, or licensed survey, especially for fences, setbacks, or boundary disputes.