06 Sep Buying a Home in a Flood Zone in St. Louis: What to Know

St. Louis floods two ways. The rivers come up slowly, as the Meramec did over New Year’s 2015 and again in May 2017. And the creeks come up fast, as the River Des Peres and Deer Creek did on the morning of July 26, 2022, when the National Weather Service measured 8.64 inches at Lambert Airport, the wettest day in the city’s records. Both are knowable before you make an offer.

Here is how to check a St. Louis address, what insurance will cost you, and what Missouri does and does not require a seller to tell you.

Read the FEMA zone, then read the MSD map

Start with the FEMA Flood Map Service Center and type in the address. According to FEMA, zones beginning with A (A, AE, AH, AO) are Special Flood Hazard Areas with at least a 1 percent chance of flooding in any year, the so-called 100-year floodplain. Shaded Zone X is the moderate-risk band between the 100-year and 500-year lines. Unshaded Zone X is minimal risk on paper.

Then check the Metropolitan St. Louis Sewer District’s Know Your Zone map, which layers the same FEMA data on a local street map and links to preparedness resources. For homes inside the City of St. Louis, the Community Development Administration also publishes a Flood Risk Map of “Disaster Risk Reduction Areas” built from the 2022 storm, including blocks where residents reported more than three feet of water.

One caution: flash flooding doesn’t respect the lines. The July 2022 storm damaged homes well beyond the mapped floodplain, which is why the City’s map combines FEMA zones with resident-reported water depths and MSD problem areas. A Zone X label means lower risk, not no risk.

Know the local geography

The Meramec River corridor is the region’s best-known floodplain. In the December 2015 flood, the National Weather Service recorded record crests of 44.11 feet at Valley Park, 46.06 feet near Eureka, and 47.26 feet near Arnold, and the river came back to nearly the same levels in May 2017. Valley Park’s downtown sat dry both times behind a $50 million levee finished in 2005; Fenton and Arnold did not. Arnold has bought out hundreds of floodplain homes since 1993, per FEMA case studies.

Closer in, the flash-flood streams matter more: the River Des Peres through Ellendale and University City, and Deer Creek through Ladue and Webster Groves. These are the places where the July 2022 storm sent water into first floors within an hour.

Flood insurance: when it’s required and what drives the price

Standard homeowners policies exclude flood. If the home is in a Special Flood Hazard Area and you use a federally backed or federally regulated mortgage, federal law (42 U.S.C. 4012a) requires flood coverage for the life of the loan, and your lender will order a flood-zone determination at application to confirm it. Outside the SFHA it’s optional but often smart near the creeks above.

The National Flood Insurance Program now prices every policy individually under Risk Rating 2.0, using flood frequency, distance to water, first-floor height, and rebuild cost rather than the zone alone, according to FEMA. FEMA’s fact sheet says 96 percent of policyholders saw either a decrease or an increase of no more than $20 a month under the new method, with most annual increases capped at 18 percent. Because rates are property-specific, the useful number is a quote on the actual house, not a national average. Ask the seller for their current declarations page.

Private flood insurance is a legitimate alternative. Lenders must accept a private policy that meets federal standards, and private carriers sometimes beat NFIP pricing on well-elevated homes.

Get an elevation certificate

An elevation certificate is a surveyor’s document showing the home’s lowest floor relative to the base flood elevation. FEMA uses it for floodplain compliance, insurers use it to refine your rate, and if the structure sits above the base flood elevation, it supports a Letter of Map Amendment that can remove the property from the SFHA entirely. Ask whether the seller has one.

What Missouri sellers must disclose (and what they don’t)

Missouri has no general statutory seller-disclosure law; the only mandated disclosure is for former meth-lab sites. What buyers rely on instead is the Missouri REALTORS Seller’s Disclosure Statement, which is contractual and based only on the seller’s actual knowledge. It does ask the right questions: whether the seller is aware of any “flood, drainage or grading problems,” whether any portion of the property is in the 100-year flood hazard area, whether the basement has had water, and whether any insurance claims were filed in the last five years.

The gaps are what a seller doesn’t know or didn’t own through. So ask the listing agent for the flood-claim history, talk to neighbors about July 2022, and look for fresh drywall, new carpet, or a recently replaced furnace in a basement.

MSD Project Clear and buyouts

MSD Project Clear is the district’s multibillion-dollar program to reduce sewer overflows and stormwater problems, funded partly by the stormwater taxes on your property bill. Ask MSD whether a capital project is planned near the address.

Buyouts are the other tool. After the 2022 flood, FEMA approved about $7.4 million to acquire eleven properties in University City, Ladue, and Webster Groves, including the Hafner Court apartments along the River Des Peres, per St. Louis Public Radio. Statewide, FEMA reports Missouri has bought out more than 4,000 flood-prone properties in 99 communities since 1993. Bought-out lots become permanent open space; a block with several empty lots is also a signal about the water.

Questions to settle before you write the offer

• What is the FEMA zone, and does the lender require flood insurance?
• What does an NFIP quote and a private quote cost for this specific house?
• Is there an elevation certificate, and is the lowest floor above the base flood elevation?
• Has a flood claim been filed here, and what happened on July 26, 2022?
• Are there buyout lots or MSD projects nearby?

A flood zone isn’t automatically a deal-breaker. Some of the best-priced homes in Valley Park, Fenton, and Arnold sit in one. What matters is going in with the map, the quote, and the history in hand.

We help buyers run this checklist every week. If you’re weighing a house near the Meramec or one of the creeks, talk to our agents or read more about our home-buying process. And to see how flood-adjacent neighborhoods are pricing compared to the rest of the region, check our St. Louis real estate market report.