An estimated 48,000 vehicles in the U.S. may have already sustained flood damage from storms earlier this year, according to new CARFAX data.

Storms between April and August impacted thousands of vehicles in states including Michigan, Wisconsin, Mississippi, Indiana and West Virginia.

Law enforcement are warning that these vehicles can make their way into the used-car market, even in cities and states far from where the original flooding occurred.

The newly flood-damaged vehicles add to the more than half a million water-damaged vehicles already on U.S. roads, according to the car history provider.

The top 10 states with the most water-damaged vehicles currently on the road are:

“Floodwater can leave behind damage that isn’t always obvious when a vehicle is cleaned up and put back on the market. And those cars can appear far from the area where the storm occurred,” said Paul Nadjarian, chief product officer at CARFAX. “With storms bringing flooding across the country, it’s a good reminder for anyone shopping for a used car to understand its reported history. A vehicle may look great on the outside while hidden water damage can create serious problems.

In addition to a free Flood Check® tool at carfax.com/flood, it is recommended that buyers have the vehicle inspected prior to purchase, looking for the following potential signs of water damage:

• A musty or moldy odor in the interior
• Damp carpets
• Upholstery or carpeting that is loose, new, stained or doesn’t match the rest of the interior
• Rust around doors, under the dashboard, on the pedals or inside the hood and trunk latches
• Mud or silt in the glove compartment, under the seats, or up higher than usual
• Brittle wires under the dashboard
• Fog or moisture beads in interior lights, exterior lights or the instrument panel