Flood risk and where to put a storm shelter

Last updated: October 10, 2026

Put a storm shelter where everyone can reach it in seconds and where it won't take on water — and never below ground in a floodplain. FEMA's grant guidance says safe rooms generally shouldn't be sited in FEMA special flood hazard areas, and that a residential tornado safe room's lowest floor should be at least one foot above the base flood elevation. In a St. Louis basement, that means a corner away from the sump and floor drains in a basement that doesn't flood. On a slab home in or near a floodplain, it means above ground.

Why flooding and tornadoes go together here

Tornadoes in the St. Louis area usually come out of strong thunderstorms with heavy rain. In the same hour a tornado warning sounds, streets flood, basements take water, and power goes out — which stops sump pumps. A shelter plan has to work in that hour, not on a dry afternoon — the household tornado plan covers alerts and drills for it.

Know your flood zone

Look up your address on FEMA's flood maps or your county's GIS. The places in our area most likely to be mapped as flood hazard areas or protected by levees:

• Missouri River bottoms — including the Chesterfield Valley, behind the Monarch-Chesterfield levee, and low ground in St. Charles County.
• Mississippi River bottoms on both sides.
• The American Bottom in Illinois — the Mississippi floodplain from Alton south to the Kaskaskia River, protected by the Metro East's 74-mile levee system.
• Low ground along the Meramec River — check FEMA's map for your address.
• River des Peres and smaller creeks throughout St. Louis County and the City.

Being behind a levee lowers flood risk; it doesn't make below-grade space a good place for a shelter.

Basement safe rooms: managing water

If your basement stays dry in heavy rain, a basement safe room is often the best option (our basement vs safe room guide explains why). If it doesn't, think again. For basement rooms:

• Place the room away from the sump pit and the lowest floor drains.
• Look at where water goes when the sump fails — the low spot — and stay out of it.
• Consider a battery or water-powered backup for the sump, so the basement stays dry when the power goes out in a storm.
• Keep the door clear of anything that could fall against it.
• Keep a flashlight, weather radio and charged phone in the room.

Garage and yard shelters

In-ground garage shelters sit below the slab, so the ground around them has to stay dry. A garage that takes driveway runoff, or a lot with a high water table, is a reason to choose above-ground instead.

Yard shelters are the most exposed to water. They need a high, well-drained site with surface water running away. In a floodplain, no.

Above-ground in a floodplain

If you're in a mapped flood area, an above-ground safe room set at least a foot above the base flood elevation follows FEMA's grant guidance. That may mean an upper-floor interior room for a reinforced build, or a raised pad. FEMA's guidance also notes properties in special flood hazard areas with grant-funded safe rooms must keep flood insurance.

Location checklist

Related guides

• Above-ground vs underground in St. Louis
• Do you need a shelter if you have a basement?
• Shelter capacity and access

Frequently asked questions

Can I put a safe room in a basement that sometimes floods? We'd steer you away from it, or toward a part of the basement that stays dry with a reliable sump backup. An above-ground unit is often the better choice.

I'm behind a levee. Is underground OK? We don't recommend below-grade shelters in levee-protected floodplains. A levee reduces risk; it doesn't remove groundwater or eliminate failure risk.

Where's the best spot in a slab house? An interior room or the attached garage, with an above-ground unit on a slab that meets spec.

Does a safe room need flood insurance? For grant-funded safe rooms in special flood hazard areas, FEMA requires flood insurance on the property. For others, ask your insurer.

Get a quote

Send your address and a note on how the basement or garage handles a heavy rain, and we'll suggest where a shelter belongs. See above-ground safe rooms, or get a quote.