Do you own a property that appears to straddle multiple flood zones?
Have you been told that even if only part of your house is in a high-risk flood zone, your whole structure is considered high-risk — and now you're wondering what that really means?
If part of your structure lies in a high-risk flood zone, insurance companies and regulators typically treat the entire structure as being in that high-risk zone — and yes, that affects your coverage and your premiums. But there are critical distinctions, and in some cases, solutions that might surprise you.
In this article, you’ll learn:
The key difference between a property and a structure when it comes to flood zones
What an elevation certificate can reveal about your risk
Real-life examples of how you can potentially change your flood zone designation
Actionable next steps if your structure crosses multiple flood zones
If any portion of your structure lies in a high-risk flood zone, the entire structure is treated as high-risk for insurance and regulatory purposes. This is true even if your property spans multiple flood zones.
While this can seem frustrating or overly cautious, the logic is grounded in risk management — if floodwaters could reach any part of your home, your entire structure is considered vulnerable.
Your property might include front yards, backyards, and side lots that cross into different flood zones. But what matters for insurance is your structure — meaning your house, garage, deck, and any attached buildings.
Flood insurance rates and regulatory requirements are based solely on where the structure is located, not the entire parcel of land.
Think of it this way: you’re not insuring your grass; you’re insuring your walls, floors, and foundation.
An elevation certificate (EC) is a critical tool for understanding your flood risk. It shows how your structure sits relative to the Base Flood Elevation (BFE) — the level at which there’s a 1% annual chance of flooding.
If any portion of the structure extends into a high-risk zone (such as Flood Zone AE), the entire structure is classified as high-risk. That classification directly affects your insurance rate and may trigger mandatory coverage requirements.
An EC can also be your best friend if you’re trying to lower your premiums — but only if it shows your structure is entirely in a lower-risk area.
There are cases where small adjustments to your home’s footprint or attachments can lead to a better flood zone designation.
Real-world examples we’ve seen:
Moving the supports of a deck that extended into a high-risk zone
Rebuilding stairs that previously crossed into a higher-risk area
Removing minor appendages that pushed a structure into an otherwise avoidable risk category
With proper documentation, permits, and planning, even small modifications can impact how your structure is classified.
Consulting with a surveyor or engineer who understands flood zones is essential if you're considering this route.
If you suspect your structure crosses flood zones — or you’ve been told it does — here’s your action plan:
Review or order an elevation certificate.
This will confirm how your structure relates to the flood zones and base flood elevation.
Consult a flood-savvy surveyor or engineer.
They can help determine if small changes (like relocating deck supports or steps) could improve your structure's classification.
Speak with your insurer or flood insurance specialist.
They’ll explain how your current zone affects your premiums and what options you may have.
Explore long-term flood mitigation strategies.
Even if you can’t change the flood zone, you can still reduce your risk — and potentially lower your premiums — through smart mitigation.
At the end of the day, it’s easy to feel stuck when you learn your home is partially in a high-risk flood zone. But knowing the difference between property and structure, understanding how elevation certificates work, and exploring the potential for reclassification can open the door to real solutions.
Flood zone rules might feel rigid — but they’re not always final. And with the right help, you might just be able to change your home’s flood risk story.