| Zone | What it is (Plain English) | Is Insurance Mandatory? |
| Zone X | Low-to-Moderate Risk. The “Safe” zone. Most of Kailua is here. Not in the 100-year floodplain. | NO. Lenders cannot require it. Policies are very cheap (optional). |
| Zone A | High Risk. You are in the 100-year floodplain, but FEMA hasn’t calculated exactly how deep the water will get. | YES. Mandatory for all federally backed mortgages. |
| Zone AE | High Risk (Detailed). Same as Zone A, but engineers have calculated the exact “Base Flood Elevation” (BFE)—the depth water is expected to reach. | YES. Mandatory. Your rate depends on how high your house sits above that elevation. |
| Zone AEF | The Floodway. The most dangerous part of Zone AE. This is the actual channel where water must flow during a flood. | YES. Plus, strict rules: you usually cannot build anything here that would block water flow. |
| Zone VE | Coastal High Hazard. The “Velocity” zone. Risk of 3-foot waves or higher during a storm. | YES. Highest premiums of all zones due to wave damage risk. |
| Zone AH/AO | Shallow Flooding. Areas of “ponding” or sheet flow (usually 1–3 feet deep) on flat ground or hillsides. | YES. Mandatory. |
To look up your home, go to the Oahu Preliminary Flood Map Slider.
The Colors: * Green (Any shade): No mandatory insurance.
The Goal: If the slider shows your property turning from Green to Blue, you are being “mapped in” and need to call an agent before June 10th to save money.
Blue/Magenta (A, AE, VE): Insurance is Mandatory with a mortgage.
Light Green or Dark Green (Zone X): The “Safe” Zone. No mandatory flood insurance. If you want a policy, it’s usually very cheap.
Blue (Zone AE): High Risk. If your house touches this, the bank will require flood insurance. Engineers have calculated exactly how high the water might get here.
Magenta/Purple (Zone A): High Risk. Just like the blue zone, insurance is mandatory, but FEMA hasn’t calculated the exact water depth yet.
Red (Zone VE): Coastal Danger. High risk from waves. This is the most expensive zone for insurance.
The “Newly Mapped” Discount: If your property is moving from Green to Blue on June 10, 2026, call your insurance agent now. If you buy a policy before the deadline, you can often lock in a much lower “Newly Mapped” rate. Waiting until June 11 could cost you thousands in higher premiums.
Impact on Selling: If you are planning to list your home and it’s being moved into a high-risk zone, disclosed this early. Buyers will need to know about the mandatory insurance requirement.
Permitting: If you are in a blue or purple zone, any new construction or big renovations will have much stricter (and more expensive) building requirements after June 10.