The devastation of Hurricane Harvey, and other storms, is creating a new problem across the country.
A new CARFAX report suggests hundreds of thousands of vehicles, once stuck in flood waters, are now back on the road.
Some estimates suggest almost a million Texas vehicles were damaged by Harvey.
Many were totaled, by insurance companies, and sold for scrap and parts. Others were cleaned and repaired. Texas law allows flood cars to be resold, as long as their history is disclosed to the buyer with a new title that labels it as "damaged".
CARFAX says the number of once-flooded cars that are back on the nation's roads jumped by 47 percent in the last year to almost half a million vehicles.
Houston has more than any other city in the country, with more than 127,000 flood-damaged vehicles.
Mechanic Derek Lang, of the Kar Doctor garage, has seen plenty of flood-cars and says he'd never knowingly buy one.
Besides the mold and rust, he says the water destroys the vehicle's mechanics and electronics.
"You get all these weird things happening, in the car," says Lang, "And that's what the corrosion causes to the electronics in the cars."
While some unscrupulous sellers actively try to hide the history of flood-vehicles, CARFAX believes there are a lot of instances of under-insured sellers trying to cut their losses.
"I think it's the product of some of the people, in the area... reselling the car themselves without telling anybody that it was flooded," says CARFAX spokesman Chris Basso.
Experts recommend a test drive and hiring a mechanic to inspect the vehicle before buying a used-car. CARFAX has also compiled a database of vehicles with high-water damage that is free to check.
Check it here: www.carfax.com/flood