Water can be a friend to a car. Cool, clear water is the best thing for washing the exterior finish. Clear water with special solvents in it is just what the windshield washer system needs to keep the glass clear. And clear water mixed with anti-freeze in the cooling system will keep the engine running happily.

But clear water is not a friend to a car if the car is submerged in it. It starts the demon rust working in areas that are not protected from it. It shorts out parts of the electrical system. It grows mold in upholstery. And, finally, it creates mechanical problems that may show up long after the submersion.

It’s much easier to deal with a car that has been submerged in salt water, such as from a coastal storm surge. A car that has been under salt water is a total loss. It can be parted out, and some usable parts retained, but salt water reacts so severely with the electrical system that there is no hope of making the car drivable again.

So, if a dealer is offering a real bargain on a late model used car, how can you tell that it has or hasn’t been in for an involuntary swim?

Check the History

You need to find out where the car came from, where it’s been. There are services that can track down the registration history of a vehicle through its serial number. However, this “title history” will not indicate flood damage. It can, however, indicate that the car came from a place and time where flood damage might have occurred.

Check for Odors

One clue that is relatively easy to follow is the odor of the interior. If there is a musty smell, even if everything looks dry, it is possible that the interior was sufficiently damp enough to cause mold or mildew to grow. To get rid of these, almost all the upholstery has to be replaced, as well as the under backing and padding. If the seller is looking to turn a quick buck, it’s likely that only the surface has been cleaned.

If the carpets and/or headliner have been recently shampooed or replaced, that should also be a strong signal. Carpets and headliner can usually go for nearly 20 years or more before needing serious cleaning or replacement.

Check for Dirt and Corrosion

If the car passes the other tests, but you still have suspicions, look for water and grit inside the car and inside the engine compartment as signs of a potential submersion. Check under the dashboard for dried mud or residue and be sure to lift the trunk mats and check for signs of water, grit, mud, or residue of any kind.

Be concerned if you notice excessive dirt, mud, or water stains in or around areas of the vehicle that aren't normally exposed to the elements.

Don't forget to look for unusual or excessive moisture in the car's gauges. Condensation inside the speedometer or other instruments is not normal, and extremely difficult to remove.

Look for rust on the inside of the car and under interior carpeting. Also, check for rust on screws inside the console or other areas of the car where water simply wouldn't reach had the car not been submerged and, finally, don't forget to check for surface rust under the trunk mats.

If the car passes all these inspections and tests, you may be getting a good deal. But it’s better to pass up on an “iffy” car and be safe than it is to take a chance and get shot down in the end.