Water In Trunk Under Spare Tire? Surprising Reasons Why This Happens!

Have you ever noticed there is water in trunk under spare tire?

Picture this: you pop open your trunk, only to find an unexpected pool of water lurking beneath the spare tire. It’s puzzling, frustrating, and quite the inconvenience. So why does this happen, anyway?

From rain-soaked streets to car washes, there are various culprits behind this scenario. Could it be a leaky trunk seal, allowing rainwater to seep in? Or perhaps a clogged drainage system is diverting water to the wrong places. Even the smallest gaps or cracks in your trunk’s armor could welcome water in.

In today’s post, we will cover the many reasons why water tends to get stuck under your spare tire, as well as some tips on how to fix this issue. Let’s dive right into it!

water in trunk under spare tire

Causes of Water in Trunk Under Spare Tire

Nobody wants to open their trunk and see water in it. However, this is a frustrating experience that some people come across with. But thankfully, there is a way to address this concern. 

First, let’s look at the most common causes of this problem, so you know why this happens.

1. Faulty Trunk Seals

One of the primary culprits behind water intrusion in the trunk is a compromised trunk seal. Trunk seals, also known as weatherstrips, are designed to prevent water from seeping into the trunk area. 

However, over time, these seals can deteriorate due to exposure to sunlight, temperature fluctuations, and general wear and tear. Once they lose their integrity, rainwater and moisture find their way into the trunk, often collecting underneath the spare tire.

2. Clogged Drainage Channels

Modern vehicles are equipped with drainage channels designed to direct rainwater and other liquids away from sensitive areas. In some cases, these channels can become clogged with debris, leaves, or dirt, diverting water to unintended places – like the trunk. This can lead to water pooling beneath the spare tire well.

3. Body and Seam Sealant Issues

A vehicle’s body and seams are sealed to provide a protective barrier against the elements. However, if the seals or sealants are improperly applied or develop cracks, they can allow water to infiltrate the trunk area. Even the tiniest gaps can serve as entry points for water, which may eventually accumulate under the spare tire.

4. Accidental Spills and Leaks

Sometimes, the cause of water accumulation isn’t related to external factors, but rather to incidents that happen within the vehicle itself. Spilled drinks, improperly closed water bottles, or even leaks from improperly sealed containers can result in water finding its way into the trunk.

5. Improper Body Repairs

Following collisions or body repairs, the structural integrity of the vehicle can be compromised. If these repairs aren’t performed meticulously, water can infiltrate through gaps or weak points created during the repair process, leading to water accumulation in unexpected places.

6. Inadequate Ventilation

In some cases, water accumulation might not be due to external sources at all. Poor ventilation within the trunk can lead to the formation of condensation, especially in areas with high humidity. Over time, this condensation can accumulate and create the appearance of water leakage.

7. Manufacturing Defects

While relatively rare, manufacturing defects can also contribute to water accumulation in the trunk. Flaws in the design or assembly process can create vulnerabilities that allow water to infiltrate the trunk area, often settling under the spare tire.

Long-Term Problems of Water Accumulation in the Trunk Under Your Spare Tire

Discovering water accumulating under the spare tire in your trunk might seem like a minor inconvenience, but its long-term repercussions can be far-reaching and potentially costly. Let’s delve into the possible lasting problems that can arise from persistent water accumulation:

1. Corrosion and Rust

Water is notorious for accelerating corrosion and rust formation, especially when it’s allowed to linger in concealed areas like the spare tire well. As water interacts with metals, it triggers chemical reactions that weaken structural integrity. Over time, this corrosion can compromise the vehicle’s framework, leading to safety hazards and decreased resale value.

2. Electrical Malfunctions

Modern vehicles are equipped with intricate electrical systems, and water infiltration can wreak havoc on these components. If water reaches wiring, connectors, or electronic modules located in the trunk, it can cause short circuits, malfunctions, and even complete failures in various systems. This can affect everything from your lights and entertainment system to crucial safety features.

3. Mold and Mildew Growth

Stagnant water creates a favorable environment for mold and mildew to flourish. The trunk’s dark and enclosed space, combined with the dampness from water accumulation, becomes a breeding ground for these harmful microorganisms. Mold and mildew growth not only releases unpleasant odors into your vehicle but also poses health risks, especially for those with respiratory sensitivities.

4. Interior Damage

Water seeping into the trunk can impact not only the spare tire area but also adjacent surfaces and materials. Upholstery, carpeting, and any stored belongings can suffer water damage. Stains, discoloration, and deterioration of these materials are likely outcomes, negatively affecting your vehicle’s aesthetics and comfort.

5. Weakening of Structural Components

Constant exposure to water can weaken the structural components of the trunk and surrounding areas. The trunk floor, supports, and related structures might gradually lose their strength, leading to compromised load-bearing capacity. This could impact the overall stability and safety of the vehicle, especially in situations like sudden stops or collisions.

6. Reduced Resale Value

Potential buyers or appraisers will be quick to notice signs of water damage in the trunk area. Corrosion, rust, mold, or electrical issues resulting from water accumulation can significantly lower your vehicle’s resale value. Future buyers might be reluctant to invest in a vehicle with a history of water-related problems.

7. Voided Warranties

Water-related damage might void warranties, especially if it’s deemed to be caused by neglect or improper maintenance. Manufacturers and dealerships could consider water damage as a result of owner negligence, leading to potentially costly repairs that you’ll have to cover out of pocket.

Water accumulation in the trunk under the spare tire goes beyond mere inconvenience – it can lead to a cascade of long-term problems that impact your vehicle’s safety, performance, and value. Taking swift action to address and prevent water accumulation is essential to safeguarding your investment and ensuring the longevity of your vehicle. 

How to Fix the Issue of Water in the Trunk Under the Spare Tire

Discovering water pooling under the spare tire in your trunk is not only a perplexing sight but also a potentially damaging issue for your vehicle.Here are some step-by-step solutions to tackle and fix the problem of water accumulation in your trunk.

1. Identify the Source

Before diving into solutions, it’s crucial to identify the source of the water. Is it due to a leaky trunk seal, clogged drainage channels, body seam issues, or something else? Inspect the trunk area thoroughly to pinpoint the origin of the water intrusion. This will help you target the problem accurately.

2. Replace Damaged Trunk Seals

If the culprit is a damaged or compromised trunk seal, it’s time to replace it. Purchase a compatible trunk seal for your vehicle model and carefully remove the old one. Clean the area and install the new seal, ensuring it’s properly aligned and provides a tight seal against the trunk lid.

3. Clear Drainage Channels

Clogged drainage channels can redirect water into the trunk. Use a soft brush or compressed air to remove debris and dirt from these channels. Be thorough in your cleaning to ensure unobstructed water flow away from the trunk.

4. Repair Sealants and Seams

If you’ve identified issues with body sealants or seams, it’s time to repair them. Clean the affected area and remove any old, deteriorated sealant. Apply a high-quality automotive sealant that is compatible with your vehicle’s materials. Ensure the sealant covers any gaps or cracks to prevent water intrusion.

5. Inspect Trunk Interior

Examine the interior of your trunk for signs of leaks or damage. Check for any signs of water stains, rust, or dampness. Address any visible issues promptly, as they might provide clues to the root cause of the water accumulation.

6. Professional Repairs

If the issue seems complex or beyond your expertise, it’s wise to consult a professional mechanic or auto body specialist. They can provide a detailed assessment, recommend the necessary repairs, and ensure the job is done correctly to prevent future water intrusion.

7. Use Trunk Liners

To mitigate the impact of any future spills or leaks, consider using trunk liners or mats. These accessories can provide an extra layer of protection for your trunk’s interior and spare tire well.

8. Regular Maintenance

After addressing the issue, make regular maintenance a habit. Check your trunk’s condition periodically, especially after heavy rain or car washes, to ensure that water isn’t accumulating.


Dealing with water accumulation in the trunk under the spare tire might seem like a daunting task, but armed with the right knowledge and steps, you can tackle it effectively. Remember to identify the source, take proactive measures, and don’t hesitate to seek professional help if needed. A dry and well-maintained trunk not only protects your belongings but also preserves your vehicle’s longevity. By following these steps, you’ll be well on your way to resolving the damp dilemma and ensuring a worry-free driving experience.

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