With increasingly common floods and a serious shortage of new cars, the odds of you buying a used car that has been in a flood are something to take seriously. Here are some steps to take to make sure you don't end up getting stuck with Ol' Salty.
First check the NMVTIS database, which is a partnership between the federal government and the insurance industry. If that checks out and you're serious about the car, spend a few bucks on a Carfax or similar paid report which may scan more records and details than NMVTIS. Even if the car still checks out it's possible that it had a flood salvage title that was "title washed" by being sold across certain state lines or that its flood damage was never reported to insurance. That's where the following DIY inspections come in.
Get inside the car and sniff. Mildew is tough to get out of a car, and if you smell it there are very few reasons other than a significant amount of water getting in by other means. It might be explained by a leaky windshield gasket or heater core, but those are no fun to tackle either, so start looking for another car.
Look under carpets and floor mats for dampness or water stains. These tend to hold water and make a fairly indelible mark on the floorplan coverings that is tricky to clean up and hide.
Look at the bare metal parts under the dashboard, like dashboard supports. Those bare metal parts should not be rusty on a late-model car, and the same thing goes for the bolts that attach the seats to the floor: Rusty ones are notorious tells that a car that has had too much moisture in it.
Look inside turn signal lenses for a dried water line, condensation or even water still in there. Modern cars have really well-sealed lights and should not have any of these signs of internal moisture.
Examine rubber floor plugs under the car. If they're clean or new against a car's typically grimy underside, that's a red flag. Floor plugs are commonly removed or replaced because someone had to drain the inside of the car.
Look inside the wheel wells for waterline marks or dried silt along a horizontal line, quite different from common wheel spray. Straight water lines are common on cars that have forded a high level of water. This test is going to be less relevant on a truck or crossover that can appropriately ford high water.
Extra points: Undo one of the multiconductor wiring connectors in the engine bay and look at the contacts inside. Most buyers won't have the chutzpah or skills to do this, but if you do and find corroded contacts in there, be wary. Electronics are probably the worst and most expensively affected part of a car when it comes to flood damage. Certain BMWs are a classic example of cars that inexplicably have key electronics mounted low in the trunk where water can pool very quickly.
These steps shouldn't take more than 10 minutes. If you plan to roll the dice on a flooded car, at least know you're doing so and get the price right.