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Back Seat Floor Wet – What’s Going On?

There are many possible reasons why the back seat of your car is wet. Leaving the interior surface of the car wet will result in mold growth. While cleaning mold inside a car is easy, you do not want it to breed. Luckily, we have researched a variety of reasons why the back seat of the car gets wet and how you can dry it.

Here are the possible reasons why your back seat is wet.

  • Leaking sunroof
  • Leaking doors
  • Leaking windows
  • Bad air conditioner evaporator
  • Bad heater

While it’s possible to keep these things from happening, they will continue if you leave them unattended. Keep on reading to learn more details on how you can get rid of wet surfaces inside your car. We will also discuss with you important details about how to keep your car dry. 

Textile car backseats, Back Seat Floor Wet - What's Going On?

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Why is the back seat of your car wet? – 5 common reasons

The reasons below suggest why the car floor surface is wet.

Leaking sunroof

An SUV on the parking lot

All car sunroofs have a seal. But these seals are not tight enough to hold water, and they drain to remove water. The evident metal frame in the sunroof is the sunroof tray which drains corners with holes. As the rain starts to fall, and the sunroof is retracted, the water that is being collected in the train will drain into the floor of the vehicle.  When you open the sunroof repeatedly, the holes will start to clog with the debris of dust and leaves. The rainwater will leak into the cabin.

Leaking doors

Car photographed under the rain

The automotive doors are not airtight. Water may seep inside the car. Water falls from the door's protective sheet and into the holes at the bottom of the car’s door. If these membranes become damaged and aged, they will not be effective.

Any water collected inside the car will be drained, but the drain holes can be clogged too. This will force the water to enter the cabin. Check the underside of the door and see if the drain holes are obstructed.

Leaking windows

Car windshield with raindrops

The rainwater can pass through the small holes of the vehicle, especially in the windows and windshields. Over time, the black rubber seal (weather-stripping) that makes the boundary of your car’s window glass will start to dry. It will become damaged and brittle and will be the cause of leaks. If the car has torn weather-stripping, rainwater may find its way to enter the vehicle.

If you plan to park outside, make sure that the weather-stripping is in good condition. You can have the seals replaced by a professional.

Bad AC evaporatorCar condenser air filter

Rainwater can seep into the vehicle when there is a leaking window, but how about on sunny days? There is something bad happening under the hood.

The car’s air conditioning system produces cold air inside the cabin and pulls the warm air away from it. The air conditioner’s evaporator will draw warm and humid air out of the vehicle. While driving, it will drain the water.

The evaporator is usually underneath the dashboard. Once it is clogged with debris such as dirt and dust, the condensation will no longer process and the leaks will start. If you notice a puddle on the passenger side carpet, then it might be due to a bad air conditioner evaporator.

Bad heater core

A removed car heater core

Even though the heater core is just a simple device, it can cause serious problems. Replacement is costly due to the part’s position which is behind the dashboard.

How can you tell if your car has a failed heater core? Here are the signs.

Lack of heat: The faulty heater may cause the car to run poorly. Any obstruction in the flow of the coolant to the core will prevent the core from keeping the cabin warm.

In some cases, the heater core will become weak and there will be leakage formation over time. But there are instances where lack of proper maintenance leads to the core’s early expiration.

Fog formation: If there is a leak in the heater core, fog will start to form because the coolant vapor will travel to the unfreeze vents. Wipe the fog off the windshield – if it smells sweet, then it is the coolant from the leaking core.

Accumulation of coolant on the floor: Since the heater core is located behind the dashboard, if there is a coolant that assembles on the floor, then there is a leak on the heater core.

The coolant level is low: If the problem with the heater core is severe, then the coolant level is probably low.

Engine overheating: If there is a low coolant level, it can cause the engine to overheat. The engine may become damaged if left unattended. Also, a clogged heater core has the potential to block the coolant flow which leads to engine overheating.

What will happen if you ignore a leak? 

Water in itself is not a hazardous substance. But if a leak is disregarded, there will be an increased likelihood of problems. Here are some of them.

  • Mold growth

Moisture causes mold growth if it doesn’t dry up. It can cause health risks for many people. This is especially true of people who have existing allergies and weak immune systems. One may experience nasal stuffiness, sore throat, and other respiratory ailments.

  • Invitation to pests

Leaving your car parked for a long period with unsecured doors or an open window is not a smart idea. If you leave the window or door open, this can be an invitation to pests. Pests such as rats will be glad to make your car their home if water is available inside.

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  • Upholstery damage

Even if your upholstery is durable and resistant, it can be damaged by moisture.

Once the liquid is contaminated, it will result in permanent stains. In time, it will decrease the value of your car if you want to sell it.

  • Nasty smell

Mildew in your car can have a foul odor like the smell of an old, wet towel.

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What should you do if you find a leak in the car? 

Once you locate the leak, it is essential to dry the cabin thoroughly because the damp surface will be the foundation of mold growth. Even if the car looks clean, there could be possible molds in the carpet, windows, or doors and you will find yourself driving a car that smells bad.

Carpets, door panels, and seats are not that hard to remove. If any of these items are wet, put them out in the sun to dry. Mop up the remaining liquid on the floor until it is completely clean. Try using a car cleaner with disinfectant to get rid of bacteria.

After drying, use a dehumidifier and close all windows. This will make the car look and smell clean.

It will take time to complete for the car to dry completely, so when you drive, turn the heater on and open all the windows for added ventilation.

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How do you keep the car from getting wet again? 

Keeping the car from getting wet takes more than not letting people bring liquids or drinks inside. In some cases, it is more complicated than you think.

Leaving damp objects inside the car will lead to condensation, thus blocking pollen filters. Condensation will not soak your car but it will create a chance for molds to grow.

Looking at a more serious condition, you will notice that your car has leaks that soak a certain area when it rains.

If there is dampness or wetness inside your car on regular basis, the best thing that you can do is to research your particular car online. Search for the best possible method of getting rid of wetting surfaces rather than repeatedly drying them off.

Final Thoughts

Textile car backseats

To be able to find answers to your problems, it is important to diagnose them first so you will know the proper method for getting rid of them.

We hope that this article has taught you about the possible reasons why your backseat floor gets wet and how you can prevent it from happening.

For more helpful tips, we suggest reading some of these related posts:

4 Of The Best Wipes For Leather Car Seats

How To Remove Hand Sanitizer Stains From Car Interior

How To Keep Car Interior Dust Free (6 Ways)