How to tell if a car has been in a flood

Why a flooded car is a bad buy

Water and silt get into the wiring, the connectors, the control units, the carpets and the seats, and sometimes into the engine and the gearbox. The damage often shows only after weeks or months: the electrics start to fail, rust spreads out of sight and mould appears. Salt or dirty water does more harm than clean rain water, and a repaired flooded car can look perfect.

It is also a safety question: airbags, ABS and stability control depend on electronics and connectors that water can corrode.

Start with the smell

Open the doors and the boot and breathe in. A musty, mouldy or earthy smell that does not go away is a warning. So is a very strong air freshener, or a cabin that looks freshly cleaned in an old car. Check the boot and under the seats, where the smell lingers longest.

Look under the carpets and in the spare-wheel well

• Lift the floor mats and, where you can, the carpet: silt, sand, mud, damp or a dried water line are red flags.
• Lift the boot floor and look into the spare-wheel well. It is the lowest point and keeps water and silt longest. A water line, or rust on the spare wheel, the jack or the bolts, is a strong sign.
• Look for a tide mark on the underside of the seats, on the door cards and in the glovebox, and behind the dashboard if you can see it.

Check the metal parts that should be dry

Look for rust where a car normally stays dry: seat rails and seat mounting bolts, the pedals, and the screws and brackets under the dashboard. A car with rust there and a low mileage does not add up.

Pull out the seat belts

Pull each seat belt all the way out and look at the webbing near its end: stains, mud marks, mildew or a stiff, dirty belt mean water reached seat level. It is a quick test that sellers rarely think of.

Lights, electrics and the engine bay

• Condensation, a water line or dirt inside the headlights and tail lights. Lights that fog once after rain are normal; a permanent line is not.
• Electrics that misbehave: windows, seat motors, the radio, the air conditioning, warning lights that flicker, odd messages on the dashboard, airbag or ABS lights that stay on.
• In the engine bay and underneath: silt in the crevices, corrosion on the electrical connectors and the fuse box, and a milky film under the oil filler cap or on the dipstick, which means water in the oil.

Check the story

• The price is far below similar cars.
• The car was registered recently, or comes from an area that had floods.
• New carpets, seat covers or upholstery that do not match the rest of an older car.
• The seller is vague about the history of the car.
• The car appears in an official record as a write-off, if your country offers one: check the VIN there before you pay.

What to do if you find signs

One sign is a reason to look harder. Two or more: walk away, or pay a workshop to check the car, including the electrical systems and the underside. Do not rely on a fresh clean-up or on the seller’s word: a cleaned car is exactly what a flooded car looks like when it is for sale.

For the other checks of a used car, see How to check a used car before you buy it. In Gulf countries, where floods and buying imported cars are both common, also read Buying a used car in the UAE.