Different Kinds of Floodplains in Bismarck, North Dakota (And What They Mean for Your Home)
By Rebecca Sabot, Real Estate Agent
© Rebecca Sabot. All rights reserved.
Floodplains sound like something you only worry about if you live on the Missouri River… until you discover your “not even close to the river” house is still mapped in a flood zone. Welcome to the fine print of real estate.
In the Bismarck area, flood risk is mapped and managed using FEMA flood maps (Flood Insurance Rate Maps, aka FIRMs), plus excellent local tools from the City of Bismarck and Burleigh County. The goal isn’t to scare you—it’s to help you make smart decisions about home buying, selling, building, and flood insurance. Bismarck ND
Below is a practical guide to the different kinds of floodplains you’ll run into around Bismarck, ND, how they’re labeled, and what they can mean for property value, permits, and insurance.
First: “Floodplain” vs “Flood Zone” (Same Family, Not Twins)
Floodplain: the land area that could flood at a certain level (like the “100-year floodplain” or “500-year floodplain”). FEMA Floodmaps
Flood zone: FEMA’s letter/number labels on the map (like Zone AE or Zone X) that tell you the type/level of risk and how the area was studied. Floodsmart
You’ll see both terms used on City and County resources, and they work together. Bismarck ND
The Big Ones in Bismarck: The 100-Year and 500-Year Floodplains
1) The 100-Year Floodplain (1% Annual Chance) — “High Risk” / SFHA
This is the floodplain tied to the base flood (a flood with a 1% chance of happening in any given year). FEMA calls much of this the Special Flood Hazard Area (SFHA). FEMA
Why it matters:
If you have a federally backed mortgage and the structure is in a high-risk FEMA zone (A/AE/AH/AO, etc.), flood insurance is typically required. Floodsmart
Building or improving property here often triggers extra requirements (elevation, flood openings, engineered designs, permits). Locally, the City of Bismarck uses floodplain development processes for projects in the SFHA. Bismarck ND
Common FEMA labels you may see here:
Zone AE / Zone A (more on those below)
2) The 500-Year Floodplain (0.2% Annual Chance) — Lower Risk, Still Not “No Risk”
This is the floodplain tied to a flood with a 0.2% chance of happening in any given year. FEMA Floodmaps
Why it matters:
It’s often associated with moderate risk areas on FEMA maps (commonly shaded Zone X). Floodsmart
Some buyers choose flood insurance anyway because the premium can be relatively affordable compared to high-risk zones—and because “outside the 100-year” doesn’t mean “immune.” (Mother Nature doesn’t read maps.)
Burleigh County provides a Floodplain Map PDF showing the 100- and 500-year floodplains—great for big-picture context. Burleigh County
The Floodway: The “Do Not Mess With This” Strip
3) Regulatory Floodway — The High-Velocity “Conveyor Belt” of Floodwater
The regulatory floodway is the channel of a river/watercourse plus adjacent land that must stay open so the base flood can pass without pushing water levels higher. Translation: it’s the area most likely to flood first, fastest, and hardest, and it’s heavily regulated. FEMA
Why it matters:
Development in the floodway is usually the most restricted, because filling/building can force floodwater onto neighboring properties. FEMA
Burleigh County’s Flood & Elevation Tool lets you toggle a Floodway layer (along with 100-year, 500-year, and even historic 2011 Missouri River flooding). Burleigh County
FEMA Flood Zones You’ll Actually See (and What They Mean)
4) Zone AE vs Zone A — Both “High Risk,” One Has More Detail
Both are high-risk “A zones,” but:
Zone AE: FEMA has run detailed studies and provides a Base Flood Elevation (BFE)—a key number for building standards and insurance. FEMA
Zone A: high risk, but often no published BFE (less detailed study). Floodsmart
Local tip: If you’re in AE, the BFE becomes a huge part of the conversation—especially for remodels, additions, and insurance quotes. FEMA
5) Zone X (Shaded) — “Moderate Risk”
Often used for areas between the 100-year and 500-year floodplains. Floodsmart
6) Zone X (Unshaded) — “Minimal Risk”
Generally outside the 500-year floodplain. That said, FEMA and NFIP resources still emphasize: flood risk exists everywhere—it’s just different levels. Floodsmart
7) Zone D — “Undetermined”
This is FEMA’s way of saying: possible risk, but not fully analyzed. Flood insurance is often recommended even though it may not be required. Floodsmart
Bismarck-Specific: Flood Maps Can Change (and South Bismarck is a Big Topic)
Flood mapping isn’t static. The City of Bismarck references FEMA mapping updates and local projects, including a South Bismarck Flood Control Project aimed at FEMA-certified flood protection for structures added to the flood risk map. Bismarck ND
Also important: Burleigh County has had preliminary FEMA FIRMs released for updated flood hazard determinations. Preliminary maps are for review/awareness—not for rating flood insurance or enforcing mandatory purchase requirements until they become effective. Bismarck ND
How to Check a Property’s Floodplain in Bismarck (Without Guessing)
Here are the three most reliable starting points:
City of Bismarck Flood Resources page (quick access to flood maps, FIRMs, and local references). Bismarck ND
Burleigh County Flood & Elevation Tool (toggle 100-year, 500-year, floodway, and historic 2011 flooding layers). Burleigh County
FEMA / NFIP flood zone guidance + Map Service Center links (definitions and official map references). Floodsmart
If you want, I’ll walk through it with you address-by-address when you’re house hunting or prepping to list. I’m a full time realtor, and this is one of those details that’s way easier to handle early than during negotiations.
What Floodplain Location Can Mean When You Buy or Sell
For buyers
Insurance: Required in many A/AE zones with government-backed loans; optional but often smart elsewhere. Floodsmart
Future projects: decks, additions, finished basements—floodplain rules can affect what’s allowed. Bismarck ND
Resale: buyers ask about flood zones; being ready with accurate info helps.
For sellers
Be proactive: know the zone, know the map panel, and be ready to explain it clearly.
Documentation helps: elevation certificates, past insurance info, mitigation improvements—these can calm buyer nerves.
Negotiations stay cleaner when you’ve got real answers instead of vibes.
Quick “Floodplain Cheat Sheet” for Bismarck
100-year floodplain (1% annual chance) = higher risk / SFHA FEMA
500-year floodplain (0.2% annual chance) = lower than SFHA, not zero FEMA Floodmaps
Floodway = most restricted, highest flow area FEMA
Zone AE = high risk + BFE shown FEMA
Zone X (shaded) = moderate risk Floodsmart
Zone X (unshaded) = minimal risk Floodsmart
Preliminary maps = helpful for awareness, not yet enforceable for insurance requirements Bismarck ND
Final Thought
Floodplains in Bismarck aren’t a reason to panic—they’re a reason to be informed. When you understand the “kind” of floodplain (100-year vs 500-year vs floodway) and the FEMA zone label (AE, A, X), you can make smarter decisions about pricing, inspections, insurance, and future plans.
If you’re buying or selling in Bismarck, I’m happy to help you interpret the map like a normal human—not a robot with a ruler.
