Hurricane and tornado seasons routinely damage a large number of cars, especially throughout the Gulf Coast region. Unfortunately, many water-damaged cars can make it to the used-car market, camouflaged as ordinary used cars. That’s a problem because water damage can be hard to spot and these cars often are transported well beyond their original region, where consumers may be less wary for such damage. Immersing a car in water can ruin electronics, lubricants, and mechanical systems. The impact may not be immediately obvious, for it can take months or years for the incipient corrosion to find its way to the car’s vital electronics such as airbag controllers. Key protections depend on accurate reporting to insurance companies, and they to national registries, and careful pre-purchase inspections. Too often, when an insurance company declares a flood-damaged car as a total loss (aka totaled), the information isn’t communicated to the potential future buyer. Once a car is totaled, it’s supposed to get a new title, called a salvage title. Those titles are usually either plainly marked (“branded” is the term used) with the word “salvage” or “flood.” In some states the warning is an obscure coded letter or number. Read More: Top pick tires for 2016 Totaled cars are typically sold at a salvage auction to junkyards and vehicle rebuilders. Reselling is legal, as long as the flood damage is disclosed to buyers on the title. Those “salvage title” cars cannot be registered until necessary repair is done and re-inspected by legal officers. Then the vehicle is given a “rebuilt” title, which allows it to be registered for highway use. But as Consumer Reports found in an investigation of “rebuilt wrecks,” some flood-damaged vehicles magically reappear with clean titles. Be especially wary of any used car with a “lost” title. One useful online tool is the National Motor Vehicle Title Information System (NMVTIS), which helps consumers run background checks. This system aims to crack down on the practice of “title washing,” where cars that have been totaled (or stolen) can get clean new titles in states with lax regulations. The NMVTIS website lists several information providers, with varying prices and services. However, if the vehicle’s owner doesn’t have comprehensive insurance coverage at the time, or the repair bill didn’t exceed a certain amount, the vehicle might not get a ‘salvage’ or branded title at all. There are only a few states that offer a “flood” title, which requires a list of any flood damage history. Otherwise, future owner couldn’t check flood history on those vehicles. Read More: Best used cars for $25,000 and less Carfax offers a free flood damage check, in addition to its for-pay vehicle history reports. Whether the vehicle’s title shows flood history or not, they are showing the “possibility of flood damage” based on flood area history and registered address at the time. For a basic check, the National Insurance Crime Bureau offers a free VIN-check service, although it doesn’t use as many data sources as some of the paid providers. Of course, vehicle-history reports are not all-inclusive and are no guarantee that a vehicle is problem-free. But they are a valued aid in screening potential cars. Ultimately, a detailed inspection is the best protection. Read More: 7 best mattresses for couples How to Spot a Flood-Damaged Car Water damage can be hard to detect, but there are some telltale signs you should be aware of: Inspect the carpets to see if they show signs of having been waterlogged, such as smelling musty or having caked-on mud. Likewise, brand-new carpets in an older vehicle may be another red flag. Check the seat-mounting screws to see if there is any evidence that they have been removed. To dry the carpets effectively, the seats must be removed and possibly even replaced. Inspect the lights. Headlights and taillights are expensive to replace, and a visible water line may still show on the lens or the reflector. Inspect the difficult-to-clean places, such as gaps between panels in the trunk and under the hood. Waterborne mud and debris may still appear in these places. Look for mud or debris on the bottom edges of brackets or panels, where it wouldn’t settle naturally. Search around the engine compartment. Water lines and debris can appear in hard-to-clean places, such as behind the engine. Look at the heads of any unpainted, exposed screws under the dashboard. Unpainted metal in flood cars will show signs of rust. Check if the rubber drain plugs under the car and on the bottom of doors look as if they have been removed recently. It may have been done to drain floodwater. If you’re from an area affected by a flood and have a car that wasn’t damaged, be aware that buyers might suspect it was. Consider having a mechanic inspect your car before you put it up for sale so that you can present potential buyers with a clean bill of health. And, of course, whenever possible, have a trusted professional mechanic assess a car before you buy it. Consumer Reports has no relationship with any advertisers on this website. This article originally appeared on Consumer Reports.