I'm buying a home: How do I assess its flood risk?

By Allstate

Last updated: August 2023

When you're shopping for a home, you may want to ask whether your potential new property is in a high-risk flood zone. But even if it's not, the truth is that any home can experience a flood. According to the Federal Emergency Management Agency (FEMA), even if you live in an area with low or moderate flood risk, you are five times more likely to experience a flood than a fire in your home over the next 30 years.

It's important to know that homeowners insurance typically does not cover flood damage, but you may be able to purchase a separate flood insurance for that kind of protection. FEMA says about 25 percent of flood insurance claims are for properties that are not in high-risk flood zones. So, no matter your home's flood risk, you still may want to consider buying flood insurance.

Before you buy a home, it's a good idea to gain a better understanding of its flood risk and steps you can take to help protect it.

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What determines a home's flood risk?

To begin to understand a home's flood risk, look at the area's flood maps, says FloodSmart.gov. These maps show a community's flood zones (which describe the land flood risk level), flood plain boundaries and base flood elevation (which predicts how high flood water may rise). Each of those are factored into a property's risk of flooding. You can locate your local flood map online through the FEMA Map Service Center or check with your local government office, courthouse or library.

In addition, you may want to ask community officials whether a flood risk project is underway. A flood risk project is an effort between FEMA and other local/state/federal partners to identify an area's risk of flooding and take steps to help reduce that risk.

Will someone tell me about a home's flood risk?

It's a good idea to do your own research, because not all states require home sellers to share the property's flood history with buyers. Flood disclosure laws vary by state. Some states may require home sellers to reveal previous flooding or leakage problems they've experienced, while other states have no requirements when it comes to sharing a residential property's flood history.

Even if your state does require disclosure, it may not mandate full transparency. For example, some states require home sellers to reveal if the property is considered at risk of flooding, but do not require them to notify the buyer about past flood damage or if the property owner is legally required to have flood insurance. If you have questions, a real estate professional may be able to help provide insights.

What is the chance the home will flood?

Suppose you learn that a home is in a high-risk flood zone. You may hear it referred to as a 25-, 50- or 100-year flood zone. It's important to understand what those terms mean. For instance, contrary to common belief, a 100-year flood zone it does not mean the property is likely to flood once every 100 years. Instead, a house that sits in a 100-year flood zone is considered to have a 1 percent risk of flooding in any given year, FEMA explains. While that risk may sound low, FEMA says that anywhere that it rains may experience a flood, which is why you may want to consider purchasing a flood insurance policy even if your property isn't considered high risk.

Keep in mind that a property's flood risk can change over time due to factors such as development, says FloodSmart.gov. So, for example, a home that's considered low or moderate risk of flooding today may be placed in a higher risk flood zone down the road.

What if I buy a house that's in a high-risk flood zone?

If you decide to buy a house in an area that FEMA has identified as having a heightened risk of flooding, and your community participates in the National Flood Insurance Program (NFIP) you'll likely be required to purchase flood insurance. Your insurance provider can help you determine whether your property is considered high or low to moderate risk for flooding and let you know how much flood insurance may cost.

If you're required to carry flood insurance, your mortgage lender will likely need you to provide proof that you've purchased a flood policy before you can close on a home loan. Flood insurance generally does not go into effect immediately — in most cases, there is a 30-day waiting period before your policy becomes active. However, that waiting period is waived at the closing of a mortgage, FEMA says. Even if you are not required to purchase flood insurance, you may decide that it's a good idea because it's possible for any home to experience a flood.

By doing some research before making an offer on a home, you may be more aware of its flood risk and better prepared if water ever threatens your new place.