<img class="styles__noscript__2rw2y" src="https://dsx.weather.com//util/image/w/ap_17254804792736_0.jpeg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0" srcset="https://dsx.weather.com//util/image/w/ap_17254804792736_0.jpeg?v=at&w=485&h=273&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 400w, https://dsx.weather.com//util/image/w/ap_17254804792736_0.jpeg?v=ap&w=980&h=551&api=7db9fe61-7414-47b5-9871-e17d87b8b6a0 800w" > John Duke tries to figure out how to salvage his flooded vehicle in the wake of Hurricane Irma, Monday, Sept. 11, 2017, in Jacksonville, Fla. (AP Photo/John Bazemore) (AP Photo/John Bazemore)

Hundreds of thousands of cars were damaged by flooding caused by both Hurricane Irma and Hurricane Harvey, and many of them are expected to be sold on the used car market, placing future buyers at a significant safety risk.

According to a new report by Carfax, the used car research firm, flooded cars on the market have already jumped 20 percent since last year, not including the influx of flood-damaged vehicles expected to be sold from the most recent storms.

Experts at CarTalk.com have determined that any car where floodwater that rose above its floor is considered "totaled ."

Floodwater damages the interior mechanical parts such as the engine, transmission and drive train of vehicles as well as their electric computer systems, making them dangerously unreliable and a safety hazard on the road.

"Flooded cars rot from the inside out as water corrodes the mechanical parts, shorts the electrical system and compromises safety features like airbags and anti-lock brakes," Carfax noted in a press release put out on Wednesday. "Health concerns are an added problem, as mold and bacteria permeate the soft parts of the car."

Flood-damaged vehicles on the used car market were already a consumer concern before the hurricanes made landfall in recent weeks.

"We've got new research to show there's 325,000 flood damaged cars out there in the market, not counting any cars coming from Harvey or Irma," Christopher Basso, spokesperson for Carfax, told weather.com in a phone interview.



(MORE: Harvey Likely Totaled 500,000 Cars: What Happens Next? )

Dick Raines, president of Carfax, said consumers need to be on high alert.

“Our data shows there’s still much work to be done in helping consumers avoid buying flood damaged cars,” Raines said in the press release. "They can, and do, show up all over the country, whether it be a few miles or hundreds of miles from where the flooding occurred. With two devastating storms already this year, it’s vital for used car buyers everywhere to protect themselves from flooded cars that may wind up for sale. Start with a thorough test drive, a vehicle history report and a mechanic’s inspection before buying any used car."

In accordance with federal law, flood damage must be disclosed on a car's title by a salesperson, according to KTVB . However, some clever auto chop shops will attempt to hide any damage in order to make a sale. After previous storms, there was a scourge of "rebuilt wrecks. "

Ted Smith, president of the Florida Automobile Dealers Association, told weather.com in an email that "there's no such thing as a vehicle MRI."

"A customer can always ask the dealer to verify that there is no damage and my new car dealers understand that they must properly represent the condition of the vehicle back to the customer," Smith explained. "However, in many instances while the dealer may not misrepresent the condition of a vehicle, they are not responsible for damage they are not aware of (remember, no MRI to see throughout). So many dealers will sell the vehicle "as is" to ensure that the customer understands that the dealer may not be aware of all previous damage."

Here are a few ways you can spot a flood-damaged car.

Check the vehicle identification number

Consumers should always check vehicle identification numbers with CarFax , Experian’s Auto Check or the National Insurance Crime Bureau's VinCheck before making any used vehicle purchases.

This will provide a vehicle history report and possibly note whether a vehicle has been reported as flood damaged or given a salvage title. Cars deriving from recently flood ravaged areas should also be deemed dubious.

According to the Federal Trade Commission , "a salvage title means the car was declared a total loss by an insurance company because of a serious accident or some other problems. A flood title means the car has damage from sitting in water deep enough to fill the engine compartment."

Thoroughly inspect the interior of the car

A musty, mildew odor is a dead giveaway that a car has been compromised by floodwater, according to Carfax.

"Be alert for damp and musty odors," Mariam Ali, a spokesperson for the American Automobile Association, told weather.com in a phone interview. "There will be dirt build-up in unusual places like underneath the dashboard."

The AAA also suggests pulling back car carpeting for signs of staining.

Potential buyers should also check inside the glove compartment or in-between the seats for the appearance of residual sludge or debris.

Some used car sellers will try to conceal the appearance of selling a flood-damaged car by making aesthetic upgrades such as a brand new interior fabric or masking scents with excessive car deodorizer or shampooed carpeting. This should be suspect especially when the rest of the vehicle appears to be weathered and raise red flags that sellers are trying to hide damage.

See if moisture is stuck in the lights

Consumer Reports notes that a "visible water line may still show on the lens or reflector." Moisture beads and fog can build up in light fixtures from flooding and is hard to remove by those attempting to resell.

Investigate wiring

The National Automobile Dealers Association advises consumers to check "electrical wiring for rusted components, water residue or suspicious corrosion."

Look for rust under vehicle

Taking a look underneath the vehicle and spotting any kind of rust is also a good way to tell if the vehicle has been damaged by floodwater. "Corrosion is uncommon in new vehicles and those that are owned and operated in warmer climate areas," the AAA said in a statement to the press.

Review if rubber drain plugs were recently removed

Consumer Reports also recommends checking the rubber drain plugs — located under vehicles and under doors — and if they appear as if they've been recently removed that should raise suspicions that they were fiddled with to drain floodwater.

Have a mechanic you trust examine the vehicle

Beyond inspecting the car yourself, many experts suggest having a trusted car expert or mechanic give a second opinion about the state of a vehicle for sale. Often times, they'll identify things that you missed on first review.