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FEMA flood zones · Iowa

Grinnell, Iowa Flood Zone Map

9,564 residents·in Poweshiek County

Coastal high risk (V, VE)FloodwayHigh risk (A, AE)Moderate (X, 500-year)Minimal (X)Undetermined (D)

Shaded areas are FEMA’s mapped flood hazard zones in and around Grinnell, Iowa. Zoomed out they are simplified; at street level the map switches to FEMA’s exact layer. Tap anywhere to check that spot, or search an address above.

Flood risk in Grinnell

The map above shows FEMA’s flood zones in and around Grinnell; tap any spot, or search an address, for the exact zone. FEMA’s flood insurance records are kept by county, not by city, so the numbers below are for all of Poweshiek County, which includes Grinnell.

8% of Poweshiek County’s area is in FEMA’s high-risk flood zones, and another 1% in shaded X (mostly the 0.2% floodplain and areas behind levees).

Full Poweshiek County flood history: disasters, storm reports and events →

The zones you’ll see on the map

Cross-section of a river floodplainDiagram: a river valley. The floodway is the channel and the land beside it; the 1%-annual-chance flood surface (the base flood elevation) covers the valley floor as zone A or AE; a narrow band higher up is shaded X, the 0.2% floodplain; higher ground is X.0.2% CHANCE A YEAR (500-YEAR)BASE FLOOD ELEVATION · 1% A YEARXAEFloodwayAEX
  1. A / AE Inside the 1%-a-year floodplain: about a 26% chance of flooding over a 30-year mortgage. AE has a mapped base flood elevation; plain A does not.
  2. Floodway The channel and the land beside it that has to be kept clear enough to carry the flood. Building here is tightly limited.
  3. X shaded The 0.2% (500-year) floodplain, plus some levee-protected and very shallow flood areas.
  4. X Outside both lines. No federal requirement to insure, which is not the same as no risk.

Every flood zone code explained →

Flood insurance in Grinnell

If a building is in a high-risk zone (A or V) and its mortgage comes from a federally regulated or insured lender, or is federally backed, flood insurance is required.

The average NFIP premium across Iowa was $1,363 a year on August 31, 2026 (premium plus the federal policy fee; the reserve fund assessment and HFIAA surcharge come on top). Risk Rating 2.0 prices each building on its own flood risk, so a quote can be far from the average.

Outside the high-risk zones it is optional, and often worth having: from 2014 to 2024 nearly one-third of NFIP claims came from outside the high-risk Special Flood Hazard Area. Quotes: FloodSmart.gov or a local agent.