Ways Floodwater Can Damage Your Car

Vehicles that have been immersed in water can suffer from comprehensive yet hard-to-pinpoint problems.

Murilee Martin | 

Jan 3, 2024 | 3 min read

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When a big hurricane hits or torrential rainfall makes rivers overflow, you'll often see the images in the news of car roofs poking sadly out of the swirls of muddy water. Hundreds of thousands of water-damaged vehicles still drive on U.S. roads today, with more joining their ranks each year. There are a few kinds of car problems you should be aware of if the water starts rising in your neighborhood or if you're considering looking for a deal on a flood-affected vehicle.

Floodwater Can Cause Mechanical Damage

When all or part of a vehicle gets submerged during a flood, the water will find its way into nearly every component if given enough time, no matter how well sealed. If the water is salty or brackish — as is often the case with flooding near coastal areas — corrosion takes place very quickly compared with fresh water. Floodwater with heavy loads of silt (as is often the case with flooding from rivers) can force grit into bearings, suspension bushings, and electrical components.

When floodwater makes its way inside a vehicle's engine and/or drivetrain, any fluids inside those assemblies will be ruined and will require replacement. Corrosion or clogging of vital passages and lines will follow quickly. Connecting rod and main bearings, piston rings, and other engine components with close operating tolerances can be damaged by floodwater corrosion and cause catastrophic engine failure.

Electrical Damage Is a Significant Concern

Perhaps most difficult of all flood damage to analyze and repair is the sort that afflicts a vehicle's electrical system. Because floodwater-caused corrosion between the contacts in electrical connectors can take weeks or months to cause noticeable problems, a flood-damaged vehicle might break down without warning long after all repairs seem to have been performed. Since modern vehicles are loaded with computer modules and digital communication systems, glitches caused by unwanted moisture or corrosion could be difficult to diagnose.

Cosmetic Damage Can Include Moldy Upholstery

A vehicle's carpeting, seat padding, and upholstery will absorb and retain floodwater, which can lead to mold, mildew, unpleasant odors, and discoloration. In most cases, total replacement of absorbent interior components in a flooded vehicle will be necessary, though damage caused by brief and partial immersion in floodwater might be repairable via a meticulous drying process.

Floodwaters Destroy a Car's Value

A vehicle damaged by floodwater and declared "totaled" by its owner's insurance company — when the cost of repair exceeds the car's value — should thereafter carry a branded title that warns prospective buyers of its past. Some states issue branded titles just for water-damaged vehicles, while others may lump them in with vehicles that have suffered other sorts of damage.

In some cases, unscrupulous vehicle sellers may have washed a vehicle's title, hiding possible flood damage or other potential problems. It's wise to check for signs of flood damage if something seems — or smells — not quite right. Pre-purchase inspections and vehicle-history reports may also reveal problems from past flooding that were not immediately obvious.

Murilee Martin

Murilee Martin is the pen name of Phil Greden, a Colorado-based writer who appreciates Broughams d'Elegance, kei cars, Warsaw Pact hoopties, and the Simca Esplanada.