Flooding can affect you regardless of where you live or what time of year it is. Hurricane season is beginning to drift further North up the East Coast. In the West, atmospheric rivers and rapid snowmelt are drenching communities. No matter where you live, it’s never too soon to understand your home’s flood risk and make sure you’re prepared.
Many people underestimate their flood risk
It’s often difficult to predict whether your home will experience flooding because governments have not done a good job publicizing information about flood risks, says Brett Sanders, professor of civil and environmental engineering, urban planning, and public policy at the University of California, Irvine. The most widely available flood maps are from the Federal Emergency Management Agency, and they’ve been shown to “systematically underestimate the areas at risk,” Sanders says.
Sanders co-authored a study on flood exposure in Los Angeles, which found that the number of people living in 100-year floodplains, or high-risk areas with a 1% annual chance of flooding, is 10 to 40 times higher than FEMA flood maps suggest. FEMA flood maps account for flood risk from large bodies of water like rivers and coastal storm surge, but not rainfall. Especially in the West, where dry conditions prevail most of the year, people don’t anticipate flood risk as much as East Coasters who contend with hurricanes regularly.
A more detailed look at flood risk
The flood model Sanders and his fellow researchers designed for LA accounted for every flood hazard: rainfall, river, and coastal.
“Our modeling approach is new and it’s the first to model the entire region at once,” Sanders says.
Historically, FEMA has mapped flood risk one section at a time, which can make them fall out of date as conditions change in between updates. The LA model relied on techniques like aerial laser scanning data and new flood simulations that account for existing infrastructure and up-to-date hydrological data. The researchers combined the flood data with estimates on who lives at each affected parcel of land, including their race, allowing them to see whether flooding was more likely to impact people from specific social groups.
It turned out risks are disproportionately high for Black disadvantaged communities.
“Even though Black people made up something like 9% of the population of Los Angeles County, the fraction of Black people in the flood zone was far greater than 9%,” Sanders says.
Knowing which specific communities and demographics are most affected by flood events can help governments better plan the scale of their recovery efforts. It helps to know, for example, that many people living in a flood-prone area can’t afford flood insurance.
How to identify your flood risk
The Los Angeles flood data is publicly available online. In other parts of the United States, a FEMA flood map may be your best option, despite its flaws. Those are available on the FEMA website. First Street Foundation, a private nonprofit that researches flood risk, also has a nationwide, publicly available flood model, and its website, Risk Factor, also maps the threat of fire, wind, and heat to a given property.
If flood mapping technology improves on a more widespread scale, homeowners everywhere could stand to benefit.
“We have shown what needs to be done for every part of the U.S.,” Sanders says. “We were able to, in a matter of a year or so, build a model and map out the flood risk facing 10 million people. That could be repeated all across the U.S.”
Preparing for flooding
If your home is at risk of flooding, there are steps you can take to protect it, like having it elevated onto a raised foundation. This can cost tens of thousands of dollars, even for small houses.  FEMA provides financial assistance for home elevation to homeowners who have been affected by floods, but Sanders says, “on the whole, the level of awareness is low.” You can also make smaller moves, like storing your most valuable items on higher levels, making sure your gutters are clean, and replacing carpeting with tiles. 
You should also buy flood insurance, since a typical homeowners insurance policy won’t cover flood damage. Prices have increased recently, but it’s a worthwhile investment if you consider that just a single inch of flooding can cause up to $25,000 in damage. 
Your home isn’t the only thing to worry about during a flood, says Elizabeth Kiss, professor and extension specialist in the department of financial planning for Kansas State University.
“You also need to understand your auto insurance policy and how that might and might not be covered with flood damage,” Kiss says.
Your auto insurance policy will generally cover water damage from floods if you have comprehensive coverage.
It’s a good idea to review all your insurance policies annually, or at least every two to three years, to see whether they’ve changed how they cover flood or any other damage, Kiss says. You should also have enough emergency savings to cover the deductibles for all your insurance policies.
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