Properly Storing a Vehicle to Prevent Moisture and Mold Growth

Properly storing a vehicle to prevent moisture and mold growth is crucial for maintaining its condition and ensuring it remains in optimal shape during periods of inactivity. Whether you’re storing your car for a few weeks or several months, following the right procedures can prevent costly damage and preserve its value

To prevent mold growth in a car whilst it is being stored, ensure that it is deeply cleaned, and the interior of the vehicle is as dry as possible. Deeply cleaning the vehicle will remove sources of nutrients mold can feed off and keeping it dry will deny mold the moisture it needs to live.

Storing a vehicle to prevent mold involves a combination of proper preparation, environmental control, and maintenance practices.

Maintaining a clean, dry, and well-ventilated environment is key to preventing mold and ensuring your vehicle remains in good condition during storage.

Clean the Vehicle Thoroughly

Clean the Interior

  • Any organic matter left in the car, over time, has the chance to become food for mold and bacteria. The better a job you can do of making sure it is as clean as possible before being stored, the less likelihood there is of having any unwanted surprises when you open, the door in a few months’ time.
  • Thoroughly clean the car’s interior to remove any trash, dirt, food crumbs, and other organic material that can attract moisture and mold. Remove all items from the car, especially those that can trap moisture or attract pests, such as food wrappers, clothes, or papers.
  • Vacuum the entire interior, floor mats, lifting carpets, moving seats, and getting into any difficult-to-reach places.
  • Condition the Leather and Upholstery: Use appropriate conditioners for leather seats and upholstery to keep them in good condition and prevent mold growth.
  • Spray Mold Inhibitors: Use mold-inhibiting sprays on carpets, seats, and other interior surfaces. These sprays can prevent mold growth by creating an inhospitable environment for mold spores.
  • Antimicrobial Treatments: Consider professional antimicrobial treatments for the interior, which can provide long-term protection against mold and mildew.

How Dust and Dirt Contribute to Mold Growth

  • Moisture Retention: Dust and dirt can absorb and retain moisture. When combined with humid conditions, this moisture can create an environment conducive to mold growth.
  • Nutrient Source: Dust and dirt often contain organic matter, such as pollen, dead skin cells, and other debris, which can provide nutrients for mold spores to thrive.
  • Surface Coverage: A layer of dust and dirt on surfaces can trap moisture underneath, creating a micro-environment where mold can grow unnoticed.
  • Air Quality: Poor air circulation in a dusty and dirty environment can lead to stagnant air, which increases humidity levels and the likelihood of mold development.

Dry the Interior

  • Remove Moisture-Ensure that the interior is completely dry before storage. Use a moisture absorber if necessary. Any moisture left inside can lead to mold growth.
  • Run the air conditioning system on the “max cool” setting for several minutes to dehumidify the air inside the car.
  • A car or vehicle doesn’t have to be “wet” to have a high enough moisture level for mold to grow. In fact, as long as the humidity level stays over 55%, mold can begin to establish itself in only 24-48 hours!
  • It is therefore advised that you keep the interior of your vehicle as dry as possible, both before and whilst in storage.
  • Any obvious signs of moisture, such as water on the surface from rain, can be dried with a cloth, and the same goes for any internal damp patches.
  • To keep the vehicle’s overall humidity as low as possible, consider leaving boxes of opened baking powder or activated charcoal throughout. These will not only help to absorb moisture but will also deodorize, eliminating any unpleasant smells.


  • Place desiccants (silica gel packs) or moisture absorbers (such as DampRid) inside the vehicle to absorb any excess moisture and control humidity.
  • Distribute them evenly throughout the car, including under the seats and in the trunk. These can help absorb excess moisture from the air.


  • Ensure the car is well-ventilated. Leave the windows slightly open to allow air circulation, but only if the storage environment is secure and dry. This helps prevent the buildup of moisture.
  • Consider using a portable dehumidifier or running the air conditioning on high for a while to remove any residual moisture.

Exterior Cleaning

Wash and Wax:

  • Begin by washing your car thoroughly to remove all dirt, grime, and road salts. This helps protect the paint and clear any dirt or debris that might contribute to mold growth.
  • Apply a high-quality wax to create a protective barrier on the paint, which can help repel moisture.

Check for Leaks and Maintain Seals

  • Inspect seals and repair any leaks in the windows, doors, sunroof, and trunk for any signs of wear or damage. Replace any damaged seals to prevent water ingress.
  • Sunroof Drains: Ensure the sunroof drains are clear and functioning properly. Clogged drains can cause water to overflow into the car’s interior.
  • Lubrication: Applying silicone-based lubricants to maintain the flexibility and effectiveness of the seals.

Additional Precautions

Remove Fabrics

  • Remove any items that can absorb moisture, such as floor mats, seat covers, and carpets, if storing the car for an extended period.

Battery Maintenance

  • Disconnect the battery or use a trickle charger to keep it charged without running the risk of electrical problems, which can sometimes cause dampness.

Fuel Stabilizer

  • Add a fuel stabilizer to the gas tank to prevent the fuel from breaking down and potentially attracting moisture.

Control the Storage Environment

Choose a Dry Location

  • If using a company to store your vehicle, you should conduct a thorough inspection of the location to ensure there are no obvious signs of damp or moisture, the location is clean and there is preferably a source of natural sunlight.
  • Use a dehumidifier in the storage area if possible.
  • Ventilation-Ensure proper ventilation to avoid stagnant air. You can slightly crack the windows if the storage environment is secure and free of pests.
  • Store the vehicle in a dry, well-ventilated garage or storage unit that is dry and has good air circulation. Avoid damp areas that are prone to humidity or flooding.
  • Baking Soda: Place a box of baking soda in the interior and trunk area. Baking soda naturally absorbs moisture and odors.
  • Use a dehumidifier in the storage area if possible.
  • Use a Hygrometer-Place a hygrometer in the storage area to monitor humidity levels. Aim to keep humidity below 60% to discourage mold growth.
  • If possible, use a climate-controlled storage unit to maintain a consistent, dry environment, this also maintains a stable temperature and humidity level.

Use a Car Cover

  • Invest in a high-quality, breathable custom-fit cover. It should extend down over the wheel wells and have straps to secure it tightly. Otherwise, wind can whip the cover against your car, leaving the paint looking like it was sandblasted.
  • Avoid plastic covers, as they can trap moisture underneath and create a perfect breeding ground for mold. A breathable cover allows moisture to escape while protecting the car from dust and debris that can act as a source of nutrients for mold.
  • Ensure the cover is fully waterproof to prevent green molds and algae’s growing on the rubber seals of your vehicle.

Underbody Protection

  • If storing the car outdoors, consider placing a tarp or moisture barrier under the vehicle to prevent moisture from the ground affecting the underside of the car.

Regularly Check on the Vehicle

  • Periodically check the vehicle during storage to ensure there are no signs of moisture or mold.
  • Check under the seats, in the trunk, and around the windows and doors.
  • If you notice any condensation or dampness, take steps to dry the interior immediately.
  • Air Fresheners-Use air fresheners or odor absorbers designed to combat musty smells and mold.
  • Periodic Ventilation-If possible, periodically open the car doors and windows to allow fresh air to circulate inside the vehicle.
  • Run the Engine-Start the engine and run it for a few minutes every couple of weeks to keep the engine parts lubricated and the ventilation system functioning reducing the chances of mold growth in the HVAC system.

Why do cars get moldy in storage?

  • High moisture levels within the vehicle itself
  • Food or organic material being left in the vehicle
  • High moisture levels in the room the vehicle is being stored in
  • The car was stored in a temperate climate between 60-80 degrees Fahrenheit


Properly preparing your car for storage is crucial in preventing moisture and mold damage. By thoroughly cleaning and drying the vehicle, controlling the climate, ensuring proper ventilation, using protective covers, maintaining the battery, regularly inspecting the car, and preventing pests, you can keep your car in pristine condition while it’s stored. These steps will help ensure that your vehicle remains mold-free and ready to use when you need it again.

A professional inspection and preparation service can effectively prevent mold issues during long-term car storage by addressing all aspects of cleanliness, moisture control, and environmental management. By thoroughly cleaning the car, managing moisture levels, inspecting and maintaining seals, and ensuring the storage environment is suitable, professionals can help keep your car mold-free and in excellent condition throughout its storage period.