Sioux City, Iowa Flood Zones
Sioux City is located at the confluence of the Missouri and Big Sioux rivers and faces flooding from both systems. Flood control infrastructure provides protection, but extreme events still pose risks.
FEMA Flood Risk Profile: Woodbury County
Based on FEMA's National Risk Index, which evaluates flood risk at the county level using historical loss data, exposure, and vulnerability.
Inland Flood Risk
Relatively ModerateEst. annual loss: $18.2M
Source: FEMA National Risk Index, county-level assessment. Individual property risk may vary.
Federal Flood Disaster History: Woodbury County
Woodbury County has been included in 8 federal flood-related disaster declarations.
These declarations affected communities across Woodbury County, including Sioux City.
Source: OpenFEMA Disaster Declarations Summaries API. Data sourced February 2026.
NFIP Flood Insurance Claims: Woodbury County
Properties in Woodbury County have filed 294 NFIP flood insurance claims totaling $1.9M in payouts since 1978. The average claim payout is $6K.
Highest-Claim Years
1990
152 claims - $808K
2019
21 claims - $276K
2024
21 claims - $655K
Claims by Flood Zone
Zone A
176
Zone AE
51
Zone X
34
Source: OpenFEMA NFIP Claims API. Data sourced February 2026.
Common Flood Zones in Sioux City
Properties in Sioux City, IA are commonly designated in these FEMA flood zones:
What Your Flood Zone Means in Sioux City
Sioux City faces flood risk primarily from river and stream overflow during heavy rainfall, snowmelt, or upstream dam releases. When rivers exceed their banks, floodwaters spread across low-lying areas mapped in AE and A zones. The most common FEMA flood zone designations in Sioux City are Zone AE, Zone X. FEMA's National Risk Index estimates the county's annual expected loss from inland flooding at over $18.2M.
Riverine flood risk in Sioux City is driven by the proximity and elevation of properties relative to nearby waterways. Properties closer to rivers with lower ground elevations typically face higher flood insurance premiums under FEMA's Risk Rating 2.0. If your property is in a Special Flood Hazard Area (SFHA) and you have a federally regulated or government-backed mortgage, federal law generally requires your lender to ensure you carry flood insurance.
River flood maps can change when FEMA conducts new Flood Insurance Studies or when development alters drainage patterns. Letters of Map Amendment (LOMA) can remove individual properties if the natural ground elevation was always above the Base Flood Elevation and the property was inadvertently mapped in the SFHA. Use our free lookup tool to check the current flood zone for any Sioux City address.
Check Your Sioux City Address
Enter any Sioux City, IA address to instantly see its FEMA flood zone, risk level, and whether flood insurance is required.
Free Flood Zone LookupSioux City, IA Flood Zone FAQ
What flood zones are in Sioux City, IA?
The most common FEMA flood zones in Sioux City are Zone AE, Zone X. Properties in these high-risk zones (SFHA) may require flood insurance with a federally regulated or government-backed mortgage.
Is flood insurance required in Sioux City?
If your Sioux City property is in a Special Flood Hazard Area (SFHA) and you have a federally regulated or government-backed mortgage, federal law generally requires your lender to ensure you carry flood insurance. Properties in Zone X are not federally required to carry flood insurance, though coverage is still recommended since about 25% of all NFIP flood claims come from Zone X properties.
How do I check my flood zone in Sioux City?
Enter your Sioux City address in the search tool above for an instant flood zone determination. Results include your FEMA flood zone, SFHA status, base flood elevation (if available), and FIRM panel information, pulled directly from FEMA's National Flood Hazard Layer.
What type of flooding affects Sioux City?
Sioux City is primarily affected by river and stream overflow during heavy rainfall. The most common FEMA flood zone designations are Zone AE, Zone X. Use the free lookup tool above to check the specific flood zone for any Sioux City address.
Has Sioux City experienced major flooding events?
Woodbury County, where Sioux City is located, has been part of 8 federal disaster declarations for flooding, hurricanes, or severe storms. The most recent was Severe Storms and Flooding in 2019. Federal disaster declarations are issued when flooding overwhelms local resources and triggers FEMA assistance programs.
How many flood insurance claims have been filed in Sioux City?
Woodbury County has recorded 294 NFIP flood insurance claims totaling $1.9M in payouts since 1978. The year with the most claims was 1990, with 152 claims and $808K in payouts. These figures cover all NFIP claims in the county, including Sioux City.
Sources
This page summarizes information from FEMA and other official resources in plain language. For full technical details, see the links below.
- FEMA National Flood Hazard LayerDirect Source
The NFHL is the source of all flood zone data shown on this page.
- FEMA Map Service Center — Search by AddressDirect Source
Look up any address to view FIRM panels, FIS reports, and LOMCs.
- NFHL Data and Map StatusTopic Page
View NFHL coverage and data freshness by state and community.
- FEMA National Risk Index — Data ResourcesDirect Source
County-level risk scores for inland flooding, coastal flooding, and hurricane used in the Flood Risk Profile.
- OpenFEMA Disaster Declarations Summaries API v2Direct Source
Federal disaster declarations filtered for flood-related incident types (Flood, Hurricane, Severe Storm, Coastal Storm).
- OpenFEMA FIMA NFIP Claims API v2Direct Source
Historical NFIP flood insurance claims since 1978, aggregated by county and state. Includes claim counts, payouts, and flood zone breakdowns.
Sources last verified: February 2026