How to Keep Mice Out of Your Storage Unit

The last thing anybody wants to find in their storage unit is mice. Whether they’re chewing through boxes, ruining your electrical goods or contaminating your unit and creating health risks, these tiny pests can be a mighty pain.

Fortunately, dealing with mice is relatively simple and while prevention is always the best cure, getting rid of mice is also fairly straightforward for those who know how.

In this guide, we’ll explore everything you need to know about mice in storage units, from spotting the signs of an infestation to getting rid of them for good. We’ll also share proactive tips for keeping your unit pest-free and explain where responsibility lies when it comes to any mice-related damage.

If you’re concerned about other pests in your storage unit, don’t forget to check out our comprehensive guide on how to prevent pests in self storage for even more expert advice.

Why Mice Are a Problem

Mice may be small, but the damage they can cause to your belongings is anything but. These tiny pests are surprisingly resourceful and can wreak havoc on your storage unit and its contents if left unchecked.

Understanding why mice are a problem is the first step toward keeping them out for good. In this section, we’ll look at what makes these pests so pesky.

They Can Squeeze Through Tiny Gaps

One of the reasons mice are such a common pest is their ability to fit through incredibly small spaces. They can squeeze through gaps as small as 10mm — roughly the width of a pencil. This means even the tiniest cracks in walls, doors and floors can act as an open door.

They Chew Almost Anything

Mice have strong teeth that never stop growing, which is why they’re always looking for something to gnaw on. While this might seem harmless, it can spell disaster for your stored items, as they’ll chew through:

• Cardboard Boxes: These get torn apart, leaving your belongings exposed to dust, dirt and further damage.
• Wooden Furniture: Mice often gnaw on furniture legs and edges, weakening structures and ruining appearances.
• Electrical Wires: This can break appliances and create future fire hazards.

They Contaminate Your Belongings

Beyond physical damage, mice leave a trail of contamination wherever they go. Their droppings, urine and fur can ruin fabrics, seep into porous materials and create unsanitary conditions. This contamination can even lead to health risks, as mice carry diseases like hantavirus and salmonella.

They’re Masters of Multiplication

Mice are prolific breeders, and what starts as a single pair can quickly spiral into a full-blown infestation. Female mice can have up to 10 litters a year, with each litter producing up to 12 pups. Left unchecked, an infestation can grow exponentially, making early prevention crucial.

They Thrive in Hidden Spaces

Storage units offer everything a mouse needs: shelter, safety from predators and undisturbed spaces. Once inside, they can build nests using shredded paper, fabric and insulation, turning your stored belongings into their own sanctuary.

How to Spot Signs of Mice

The earlier you detect a mouse problem, the easier it is to address. Mice are nocturnal and prefer to stay hidden, so spotting the signs they leave behind is crucial. Here’s what to look for:

• Droppings: Small, dark and shaped like grains of rice. These are often found near food sources, nesting areas and along their frequently-used pathways.
• Gnaw Marks: Look for bite marks on cardboard boxes, wooden furniture and plastic containers. Fresh marks are light in colour, while older ones darken over time.
• Nesting Materials: Shredded paper, fabric and insulation piled together is a sign that mice (or rats!) could be nesting in your unit.
• Footprints & Tail Marks: In dusty areas, you may be able to make out tiny footprints and faint tail drag marks.
• Sounds & Smells: Scratching, scurrying and squeaking are all telltale signs of nearby mice. You might also notice a musty, ammonia-like smell from mouse urine.
• Damaged Items: Torn fabrics, gnawed packaging or holes in stored goods are also signs of mouse activity.

If you’re concerned about mice in your storage unit, then the first thing you should do is check your unit and belongings for any of the signs listed above. Be sure to take a torch with you so you can thoroughly inspect the corners, underneath stacked items and along the walls. Mice tend to stick to the shadows, so careful examination can help uncover early signs of activity.

Pro Tip: There are two things that most people don’t know about mice: they’re extremely incontinent, meaning they leave urine trails wherever they go, and their urine glows under UV light. This means that with the help of a relatively cheap UV light, you’ll easily find evidence of mouse activity.

How to Get Rid of Mice in Storage Units

As anyone who’s had to deal with mice before will know, finding mice in your storage unit is more than just a nuisance. It’s not only about the damage caused to your belongings, it’s about evaluating that damage and taking the time to deal with the problem.

Now, assuming you’ve already checked your unit and its contents carefully for damage, contamination or any of the other signs we’ve listed above, you’ll be glad to know that if you do have mice, then we know how to get rid of them.

In this section, we’ll share the three simple steps to get rid of mice in your storage unit, for good:

1. Remove Infested Items

To get rid of the mice, you need to start by getting rid of anything damaged beyond repair or severely contaminated. Anything that can’t be salvaged may attract more mice and pose significant health risks, which is why it’s important to remove any such items promptly and responsibly.

2. Clean the Unit Thoroughly

Cleaning is about more than just tidying up; it’s a crucial step to eliminating scent trails and debris that might encourage mice to return. Mice rely heavily on their sense of smell to navigate and locate nesting areas, so removing all traces of their activity is essential. A thorough clean-up also helps protect your belongings from further contamination.

Here are some additional cleaning tips:

• Protect Yourself: While you don’t need a hazmat suit, it’s important to wear gloves and a mask to protect yourself from any bacteria or viruses that may be present.
• Clear & Contain: Sweep up any debris and dispose of it in a sealed bag.
• Disinfect Everything: Clean all surfaces, especially corners and baseboards, with a strong cleaning solution that neutralises odours and bacteria.

3. Set Traps or Call a Professional

If you suspect mice are still present in your unit, it’s important to take immediate action. Start by placing humane traps or snap traps near any potential entry points or areas with visible activity. For larger infestations, it’s worth speaking to a pest control expert to ensure the problem is 100% resolved.

How to Keep Mice Out of Storage Units

Once you’ve dealt with mice in your storage unit, the next step is ensuring they don’t come back. Prevention is the key to keeping your belongings safe and your unit pest-free. With a few proactive measures, you can make your storage unit as uninviting as possible for mice, here’s how:

Seal All Openings

Mice can squeeze through even the smallest gaps and cracks, so it’s important to inspect your unit for any potential entry points. Look for cracks or holes in walls, doors and floors and seal them with steel wool and expanding foam. While the foam will help fill the gap, the steel wool will stop mice from chewing their way through to your unit.

Use Airtight Containers

If you’ve been using cardboard boxes in your unit, now’s the time to replace them with sturdy, airtight plastic containers. Not only do these deter mice, but they also protect your belongings from other risks, such as water damage.

Never Store Food

Any storage facility worth its salt will have strict rules regarding the storage of certain items, with food very high on the list. Why? Because even trace amounts of food or crumbs can attract mice. You should always double-check and clean all your items to ensure no food — not even the smallest of morsels — can be found in your unit.

Keep Your Unit Clean & Organised

Cluttered spaces provide hiding spots and nesting materials for mice. Keep your unit tidy and organised, with clear pathways for easy inspection. For more useful information, check out our guide on How to Organise a Storage Unit.

Use Natural Deterrents

Scents like peppermint oil, cloves and ammonia have been proven to repel mice. Soak cotton balls in these substances and place them around the unit, particularly near entry points and in corners.

Pro Tip: Ask your storage provider about their pest control policies and whether they can assist with preventative measures. Some facilities may even have regular inspections or recommendations to help keep pests at bay.

Legal Responsibility and Insurance

If you’ve found mice in your unit, you might be wondering whether your storage provider has any legal responsibility to address or compensate for pest-related issues. The short answer? It depends.

Are Storage Providers Responsible?

Most storage facilities take reasonable steps to prevent pests, such as maintaining clean premises and conducting regular inspections. However, the exact responsibility often depends on the terms and conditions in your rental agreement. It’s always worth checking the fine print in your contract to see whether pest control is mentioned.

In general, storage providers aren’t liable for damage caused by pests unless there are clear signs of negligence on their part — such as failing to address a known infestation. This means protecting your belongings from pests usually falls on you, the tenant.

Why Insurance Matters

Even with the best precautions in place, there’s no such thing as a 100% pest-proof guarantee. That’s why having self storage insurance is so important. Some policies may cover pest-related damage, while others might exclude it entirely.

Here are a few tips to ensure you’re covered:

• Read Your Policy Carefully: Check whether pest-related damage is included in your coverage, ideally before you take out a policy.
• Ask Your Provider: If you’re unsure, speak to your insurance provider to clarify any pest-related exclusions or limitations.
• Consider Additional Coverage: If pest damage isn’t covered, look into specialist storage insurance that includes this protection.

It’s worth noting that some storage providers offer their own insurance policies (especially the big brands). However, you do have the right to consider third-party insurance providers, which may offer more extensive and affordable coverage.

Pro Tip: Always compare insurance options to ensure you’re getting the best coverage for your needs.

FAQs

What is the best mouse repellent for storage?

The best mouse repellents are natural ones, such as peppermint oil, cloves and ammonia. Soak cotton balls in these substances and place them around the storage unit, especially near entry points or in corners. Ultrasonic devices, which emit high-frequency, sounds can also keep mice away without causing them any harm.

What smells do mice hate the most?

Mice are particularly sensitive to strong smells, with peppermint oil being one of the most effective natural deterrents. Other smells they don’t like include cloves, ammonia, vinegar and citronella. Use these scents strategically around your unit to keep mice at bay.

Should you put mouse traps in a storage unit?

Yes — placing traps can help you catch mice before they cause any significant damage to your belongings. Snap traps and humane traps both provide effective solutions, but you must remember to check them regularly to ensure humane treatment and proper disposal. Place traps near suspected entry points or areas where you’ve spotted activity.

What sound do mice hate?

Mice don’t like high-frequency sounds, which is why ultrasonic sound emitters can be effective at keeping them away. These devices emit sounds that are inaudible to humans but incredibly irritating for mice. However, they work best as a preventative measure and should be used alongside other pest control strategies.