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Car Smells Like Mildew After Rain: Causes and Solutions

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Car Smells Like Mildew After Rain

When you enter the car after rain, that musty smell of mildew can hit your nose. Sometimes, the car can smell earthy or vinegary. Whatever the smell, it makes your driving experience awful.

But why does a car smell like mildew after rain? Mold or mildew is the main reason behind your car smelling after rain. Sometimes, it can be the excess moisture inside the HVAC system that causes the smell. Fabrics or carpets in your car can also get wet if windows are slightly open during rain.

Let’s learn all the possible causes of mildew smells in your car and how to fix them.

What Causes Your Car to Smell Like Mildew After Rain?

Mold rapidly grows in damp conditions. After a long pour of rain, several places in your car can be the perfect habitat for mold colonies. 

Car Smells Like Mildew After Rain

Though mold mostly grows on porous surfaces, mildew can be found on non-porous surfaces with high moisture levels. Sometimes, the situation even worsens due to your fault. Here are the leading causes of your car smelling like mildew.

Leaks in the Body Panel

If your car is too old, it can develop cracks in the body panel. Broken seals in many places let rain enter your car. Seats, carpets, and other parts can get wet if the car remains under such conditions for a long time. This condition is highly suitable for mold and mildew growth. 

What Causes Your Car to Smell Like Mildew After Rain

Air Conditioning System

The evaporator fitted in your vehicle can be responsible for mold growth. It should drain the water present in the air out of the vehicle through drain tubes. But if the tube is clogged, there might be poodles of water inside the evaporator case. 

Air Conditioning System

Sometimes, the water can leak into the cabin, leaving seats and carpets wet. Or, when you turn on the air conditioning system, mold spores can be blown inside the cabin. It will cause the car to smell like mildew. Using de-fogger while raining can also cause the same problem.

Wet or Muddy Shoes

You can unknowingly import mold spores into the car by stepping inside with wet or muddy shoes. When you walk in the rain or mud, mold spores can come in contact with your shoes. 

If you don’t clean the shoes before getting inside the car, mold finds its place on the carpet and proliferates. This can also cause a mildew-like smell.

Food or Drink Waste

While you eat inside the car, some food particles or drink spills can remain in the car until you clean them. They dry out slowly, and the evaporation increases the cabin’s humidity. These particles are often out of sight and the suitable place for mold to grow.

Wet Clothes

If your clothes are wet due to rain or sweat and you sit inside the car, seat covers can get wet too. This can increase mold growth and create that musty smell you get the next time you enter the car. The smell can be like sweaty socks if you leave the car locked for a long time.

How to Identify the Source of Mildew Smell?

How to Identify the Source of Mildew Smell

Identifying the mold habitat is the first thing to do when your car smells like mildew. Though the smell might vary a little depending on the source, you have the following indications to consider.

  • After you step inside the car, don’t turn the AC on. Sniff out for mildew smells. If the smell is already there, you should check seat covers, carpets, cushions, or other upholstery for mildew smells. As mold isn’t visible to the naked eye, a visual inspection might not bring any results.
  • If the smell inside the car is okay before turning on the AC and starts increasing after turning it on, the evaporator case may be the culprit. Until the system is cleaned or fixed, you will continue to get a mildew smell inside the car.
  • Check for any sign of wetness inside the car. The moisture can be caused by food particles, drink spills, or wet clothes you forgot in the car. Also, check the carpets for signs of wetness or dry mud.
  • You should check the body panel for cracks or broken seals. Mildew can grow in those crevices and create a smell inside the car.

How to Remove Mildew Smell From Your Car?

How to Remove Mildew Smell From Your Car

Removing the odor and removing the mold habitat are two different things. Let’s first focus on eliminating the smell from the car.

Keep the Car Under the Sun

This is the most basic step to get rid of the musty smell in your car. After raining, you should park the car under the sun for a few hours. All the windows should be open so that fresh air can circulate throughout the car. 

It is better if you can keep the doors open but keep your eyes on the car while doing this.

Use Air Freshener In the Cabin

A few sprays of air freshener can neutralize the unpleasant odor inside the car. But you should be careful about air fresheners. 

If you spray too much air freshener inside the vehicle, it might cause allergies. The excessive spray may cocktail the smell, which will worsen the situation.

Watch this video before removing mildew smell: Removing NASTY mildew smell from your car’s interior- Steps, products and tips!

How to Clean Mildew Sources In the Car?

Cleaning the habitat of mold or mildew is the most effective step in removing bad smells from your car. You can do it in several ways. Check the following.

Use a Vacuum Cleaner

Cleaning all possible areas inside the cabin can remove mildew colonies. Focus on every small debris or food waste while cleaning so no mold can remain in the car.

How to Clean Mildew Sources In the Car

Use Cleaning Sprays or Solutions

It is better to clean all the upholstery inside the car thoroughly. You can use non-abrasive chemical cleaners to clean seat covers, carpets, plastic, or other porous and non-porous surfaces. 

Using mild soap will also do the job. Be sure to dry out the cabin entirely before using the car.

Tips to Prevent Mildew From Growing In Your Car

Disinfect the Cabin and Vents

After cleaning the cabin, you must spray disinfectant solutions to eradicate mildew habitats. Don’t forget to spray the solution inside the AC vents to remove any mildew hiding there. Also, clean and disinfect the sunroof drains and wiper mounts.

Tips to Prevent Mildew From Growing In Your Car

Tips to Prevent Mildew From Growing In Your Car

Preventing mildew growth is much easier than evicting them. You can follow these tips to make it difficult for mold and mildew to grow.

  • Ensure there are no leaks in the car to prevent wetness
  • When you park the car, turn on fresh air circulation. It will eliminate the stale odor and keep your car smelling fresh
  • Use floor mats to prevent snow or mud from reaching your carpets
If you’re dealing with a car smell that’s hard to ignore, you may be interested in our articles on why your car smells like burning rubber when the heater is on or when idling. Our article on car smells like burning rubber when the heater is on explains the common causes of this problem, including issues with the heater blower motor, engine oil leaks, and damaged serpentine belts. Meanwhile, our article on car smells like burning rubber when idling discusses the possible causes of this smell, such as a worn-out drive belt or a malfunctioning alternator. If you’re experiencing similar issues, these articles may help you diagnose and solve the problem.


Here are answers to a few commonly asked questions. 

Q: Does mildew smell to go away by itself?

If you leave the car open, the smell will fade a bit. But it won’t go away until you thoroughly clean the mildew sources.

Q: What can you use instead of chemical cleaners?

If you don’t have a store-bought cleaner, you can use a mix of baking soda and vinegar to remove the mildew smell. Placing freshly cut lemon wedges might also kill the smell.

Q: Is breathing in mildew harmful?

It can vary from one person to another. Allergic people can have a hard time after breathing mildew. Also, it can cause problems like a stuffy or itchy nose, wheezing, irritation, etc.


To conclude the discussion, we want to recap why car smells like mildew after rain. It is primarily because of mold growth inside the car cabin or air conditioning systems. Soaked upholstery is a big source of these microorganisms. 

We showed you how to identify the sources of mildew smell and clean them to remove mildew growth. You should also follow preventive measures to keep mold from growing in your car. This guide should help you enjoy a fresh interior the next time you drive it.

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