Flood Zones: What You Need to Know

We’ve all seen the images on television: homes with water up to the windowsills or, even worse, the roof. After a significant weather event or during the spring snow melt, it’s not unexpected to see flood waters inside homes near the coast and rivers. But 41 million Americans live inside a designated flood zone and may not know it–including you.

It’s not scare-mongering. A Fannie Mae 2022 study revealed that 40% of homeowners inside a high-risk flood zone had no idea their property was in that zone. The same amount didn’t carry flood insurance on their homeowner’s insurance policy. Given how devastating flood damage can be to properties, millions are financially on the hook for their property losses.

With maps redrawn as scientists better understand the local factors contributing to flooding, your home may be inside a flood zone, and you don’t know it.

aerial view of a flooded area in New Orleans

Understanding Flood Zones

A flood zone is an area identified as at-risk for water intrusion in an area that is normally dry land. The Federal Emergency Management Agency (FEMA) determines the risk based on factors such as elevation, water flow, and proximity to bodies of water. It then labels an area as high, moderate, or low risk of flooding based on its potential. It marks the boundary lines for 100-year and 500-year flood events.

The purpose of designating flood zones is to help communities plan for potential flooding events and minimize the damage caused by them. They are why cities, counties, and states pass building ordinances requiring coastal and waterfront homes to be elevated a certain amount of feet. To minimize damage, they are elevating the property above the base floodplain.

Flood maps are not static maps. Scientists regularly update them as they better understand how geographies and changing landscapes impact water flows. Land development also impacts how waters flow over surfaces, so new construction can influence maps, too. And, as climate changes impact coastlines, new maps are being created. Louisiana updated its flood maps in 2023 to reflect its sinking coastlines.

Flood Zone Designations

Some areas are labeled Special Flood Hazard Areas, indicating a high risk of flooding during a 30-year cycle. At a minimum, these areas are subject to a 1% annual chance of flooding, often referred to as the “100-year flood” or “base flood elevation.”

Base flood elevations estimate the level of water that could be expected to rise during a flood with a 1% chance of occurring that year. These projected figures on are maps written as “EL” followed by a number estimating the number of feet waters could rise in a 100-year flood event.

United States Map with highlights on flooded areas

Areas are then given flood zone categories of different levels to indicate the severity of potential flooding. The levels include:

Zone A: The most high-risk flood areas carry an “A” designation. The category is further subdivided to offer more specific data, for example, AE, AO, or AH, each indicating a different type of flood risk. The average depths of these projected flood zones are 1 to 3 feet. All homes in Zone A have mandatory flood insurance purchase requirements.

Zone B (or Zone X – Shaded): These areas have a moderate flood risk, meaning they fall between the 100-year and 500-year floodplain boundaries. It could also be areas with a lesser risk base floodplain, like those protected by levees, or shallow flood areas less than one foot.

Zone C (or Zone X – Unshaded): These areas are at minimal risk of flooding as they are outside the 500-year floodplain. It could be areas with undetermined risk.

Zone V: This designation is for coastal areas that, in addition to having a 1% or greater chance of flooding yearly, also face hazards associated with storm waves. Coastal flooding combined with storm-induced waves and erosion increases damage risk. FEMA estimates their chances of flooding within a 30-year mortgage to be 26%.

Keep in mind that living in a lower-risk zone doesn’t mean flooding is impossible; it only means that the risk is statistically lower. Refer to the most up-to-date flood zone maps to understand your property’s flood risk.

Why Flood Zones Matter

According to FEMA, even shallow flooding can be devasting. Just one inch of water in a home can cause up to $25,000 in damage. Unfortunately, flooding is the most common natural disaster in the United States. Living in a flood zone means your home is at risk, which can cause significant damage and financial loss.

Knowing the flood risk can help home buyers and property owners make informed decisions about purchasing or renovating a home. If you want to buy a property or make renovations in a flood zone, you may need to take additional precautions or buy extra insurance to protect your investment.

Flood maps serve another crucial purpose: to assess flood insurance requirements and accurately estimate policy costs. Insurance agents and lenders rely on FEMA’s maps to vet who requires coverage and how much risk they are underwriting. Flood Insurance Rate Maps (FIRM) also influence mandatory building code requirements, floodplain management requirements, and flood insurance requirements. In fact, if the home is inside high-risk Zone A or V and the homeowner carries a federally-backed mortgage, the owner must purchase flood insurance as a loan condition.

Where to Find Updated Flood Zone Maps

Better analysis of weather patterns, landscape changes, and water movement has led to more accurate mapping. FEMA periodically releases updated maps in conjunction with the National Flood Insurance Program (NFIP). For instance, in 2023, 54 flood maps spanning from New Mexico to Massachusetts were officially updated or revised.

Changing a map is a long process that includes input from engineers, floodplain administrators, and surveyors. All new proposed maps are open for 90 days for public review.

Access the latest maps in your community at the FEMA Flood Map Service Center. Here, you can search your address and see any past amendments to the flood risk.

Another resource could be your county or city’s building department, emergency services department, or a local floodplain manager.

Building in a Flood Zone

If you are considering building a new home in a flood zone, working with a reputable builder with experience constructing in these areas is essential. They should know the necessary precautions and design considerations to help protect your home from potential flooding.

Additionally, use the maps to look up if the property is in a high-risk area. You may need to obtain permits or adhere to building codes specific to your flood zone. Generally speaking, new coastal properties often have elevation requirements. Low-lying inland areas could have particular rules about septic systems to protect water supplies in a flood event.

You can also use the information to gauge your flood insurance premium. Properties in high-risk areas, primarily Zones A and V, have mandatory flood insurance purchase requirements.

Flood Insurance Policies

Living in a flood zone impacts your homeowner’s insurance requirements. Most standard policies do not cover flood damage.

The cost of flood insurance to protect your home and belongings will depend on factors such as your annual flood risk, your home value, and the coverage options you choose. Luckily, FEMA’s National Flood Insurance Program (NFIP) covers about 90% of the flood insurance market. It is a public network of 50 insurance companies serving 23,000 communities. Homeowners also have private flood insurance providers that may provide some home coverage.

Living in a Flood Zone

Protect your home and financial well-being. As FEMA warns, no home is entirely “low risk” regarding flooding. Stay informed about updated flood zone maps, and make sure you have adequate flood insurance coverage to prepare for potential flooding events. Taking these steps helps you be better prepared and have peace of mind knowing that your home is protected.

FAQs

What are the flood insurance purchase requirements?

Any home or business built in high-risk flood areas that finance their home will have to make a mandatory flood insurance purchase. Even if you are in a moderate flood hazard zone, the mortgage lender may make carrying flood insurance part of the loan terms. You must purchase flood insurance that is either the lesser of:

the loan’s outstanding principal balance
the maximum coverage limit of the National Flood Insurance Program

As of 2024, NFIP coverage had a maximum of $250,000 for non-condominium residential real estate. Without flood insurance, you may not qualify for federal financial assistance if there is a flooding event.

Carriers assess both the level of flood risk at the home and the replacement cost of the home.

Won’t Federal Disaster Assistance help me if my home is flooded?

Federal agencies like the Federal Emergency Management Association (FEMA) are designed to provide basic assistance after a declared natural disaster. Your home only qualifies for some assistance if it falls under a federally designed disaster zone and, if you lived in a high-risk zone, made the mandatory flood insurance purchase. Additionally, FEMA grants and loans may not fully cover the cost to rebuild or repair the home.

How do I file a flood insurance claim?

Start by documenting the flood damage. Separate damaged and undamaged materials, and make a list of lost items with any receipts if you can find them. Have your insurance carrier and policy number available. Contact your flood insurance carrier and work with the adjuster to create a proof of loss claim. All flood insurance claims must be filed within 60 days of the flood event.

How much does flood damage cost?

A single inch of floodwater can lead to $25,000 in damage, according to FEMA. River or stream floods, like in flood zone AO, have average depths of 1 to 3 feet. This areas have a 26 percent chance of flooding during a 30-year mortgage. In 2021, the average residential flood claim was for $44,401 in damages. The average payout from the NFIP was $55,000.

Sources: