Closing Up Camp for Winter: How to Keep Mice Out of Your Lake House and Camper

Before you close up camp for the winter, take one more look around the kitchen, basement, and storage areas. Mice may already be looking for a way inside.

A seasonal cottage or camper can sit empty for months during a New Hampshire winter. With nobody coming and going, mice have time to settle into insulation, bedding, cabinets, and other sheltered spots. They don't need the heat running, either. A dry place out of the wind is often enough.

The best way to keep mice out of a camper or lake house is to remove food and nesting materials, seal openings, and deal with any existing rodent activity before you leave. Dryer sheets and peppermint oil won't protect a building with gaps around its foundation or plumbing.

If you own a camp near Newfound Lake, Squam Lake, or Lake Sunapee, this checklist will help you prepare the cottage, camper, and outbuildings for winter. It also explains when professional rodent control may be needed.

Why Closed-Up Camps and Campers Get Mice Every Winter

An empty camp gives mice something they don't often find outdoors in winter: a sheltered space where they can nest without much disturbance.

Once you lock up for the season, there may be nobody around for four or five months. No doors opening, no regular cleaning, and no one checking for fresh droppings or gnaw marks.

Mice can make themselves comfortable long before anyone notices.

Which Mice Get Into New Hampshire Camps?

House mice aren't the only species that enter seasonal properties.

Around wooded lakefront lots, deer mice and white-footed mice are also common. Both can enter cabins, sheds, garages, and campers.

They may build nests in insulation, stored blankets, upholstered furniture, or other quiet spaces.

And getting inside doesn't take much. A mouse can fit through an opening about the width of a pencil. If you're curious about how small a hole a mouse can fit through, even a gap that looks insignificant deserves a closer look.

By spring, mice may have damaged insulation, chewed wiring, or contaminated bedding and stored belongings.

That's why the best time to check for openings is before you leave, not when you return.

Closing Checklist for Your Camp or Lake House

Use this checklist when you're getting the property ready for winter. Don't forget the shed, garage, or boathouse if you have one.

Kitchen and Pantry

• Take home all food, including unopened packages.
• Remove pet food, birdseed, grass seed, and other stored food products.
• Empty pantry shelves and kitchen cabinets.
• Wipe down counters and clean crumbs from drawers.
• Clean behind and underneath the stove and refrigerator where accessible.
• Empty, defrost, and clean the refrigerator. Leave the door propped open after switching it off.

Mice can chew through cardboard boxes and thin plastic packaging, so leaving unopened cereal, crackers, or pasta behind isn't a good idea.

Even some storage containers aren't as secure as they look. Our guide explains whether rodents can chew through plastic storage bins.

If the property will be empty all winter, take the food home rather than leaving it in storage.

Bedding, Linens, and Furniture

• Wash and dry bedding before storing it.
• Put sheets, blankets, towels, and cushions in sturdy containers with tight-fitting lids.
• Cover mattresses with suitable protective covers.
• Remove loose paper, cardboard, and old newspapers.
• Check closets, drawers, and upholstered furniture for signs of mice.

Fabric, paper, and insulation make useful nesting material. A stack of blankets in a closet or a box of old magazines can give mice plenty to work with.

Entry Points to Seal Before You Leave

Walk around the outside of the building and look closely at places where pipes, wires, and vents pass through the walls.

Then check the accessible areas inside.

• Inspect plumbing and utility openings under sinks and through the foundation.
• Check foundation joints, basement openings, and sill plates.
• Look at dryer vents, bathroom exhaust vents, and range hood flaps.
• Check weatherstripping and door sweeps.
• Inspect crawlspace vents for damage.
• Look for openings around chimneys, wood stove connections, and roofline penetrations.
• Repair damaged screens and vent covers.

Small openings can often be closed with rodent-resistant materials such as copper mesh or steel wool combined with an appropriate sealant. Hardware cloth may be suitable for protecting certain larger openings and vents.

Expanding foam alone isn't a reliable barrier. Mice can chew through it.

Be careful around chimneys, heating equipment, and ventilation openings. Never block required airflow or use materials that aren't suitable for the temperatures involved.

If you find gaps you can't safely reach or aren't sure how to seal, have them inspected before closing up.

Outbuildings, Boats, and Stored Vehicles

Mice don't limit themselves to the main cottage. Sheds, boathouses, garages, and vehicles can offer shelter, too.

• Remove birdseed, grass seed, food, and other stored items that may attract mice.
• Check doors, vents, and utility openings.
• Store belongings off the floor where practical.
• Remove food wrappers, paper, and loose fabric from boats and vehicles.
• Inspect accessible engine compartments during winter visits.
• Check the engine bay and cabin air filter before using a stored vehicle in spring.

Mice sometimes nest around vehicle wiring and engine compartments. If they chew through insulation or wiring, you may not discover the damage until you try to start the vehicle.

Keeping Mice Out of a Camper Over the Winter

Wondering how to keep mice out of a camper for winter? Start with the areas you don't normally see.

Campers and RVs have openings for plumbing, electrical wiring, propane lines, and other connections. Some are hidden underneath the vehicle or behind exterior panels.

Check the Camper's Entry Points

Before putting your camper into storage, inspect:

• Plumbing and electrical penetrations
• The underbelly and enclosed service areas
• Slide-out seals
• Propane line openings
• Generator compartments and ventilation openings
• The opening where the shore power cord enters
• Exterior storage compartments and door seals

Look for damaged seals, loose covers, and gaps around wiring or pipes.

Use suitable rodent-resistant materials where repairs are needed, but don't block ventilation, drainage, or access required for the camper's equipment.

If you're unsure whether an opening is intentional, check with an RV service technician before sealing it.

Choose a Good Storage Spot

If possible, park your camper on gravel or pavement rather than tall grass.

Keep it away from woodpiles, brush, and piles of stored materials that provide cover for rodents.

Cut back tall grass and vegetation around the storage area before winter.

Empty the Camper Before You Leave

Before putting your camper into storage, remove all food, including snacks, spices, and pet treats. Give cabinets, drawers, and under-seat storage areas a thorough cleaning, making sure there are no crumbs or food scraps left behind. Take out paper towels, tissues, napkins, and other loose paper products that mice could use for nesting. Store bedding and cushions in sealed containers whenever possible, and leave empty cabinets and drawers open to make them less inviting as hiding spots. Before locking up, check for droppings, gnaw marks, or other signs that mice may already be inside.

If you visit the camper regularly during winter, snap traps can help you monitor for mice. Place them along walls and known travel routes, and check them during your visits.

Don't leave traps unattended for months and assume the problem is handled.

For anyone trying to keep mice out of a camper during winter storage, sealing entry points and removing food will do far more than leaving scented products inside.

Do Dryer Sheets, Peppermint Oil, and Irish Spring Soap Work?

Dryer sheets, peppermint oil, and Irish Spring soap come up often in conversations about keeping mice out of campers.

Unfortunately, none is a dependable solution for a property that will sit empty through a New Hampshire winter.

Strong scents may discourage mice temporarily, but they fade. A mouse looking for shelter can still enter through an opening in the floor, wall, or foundation.

Ultrasonic repellent devices aren't a reliable substitute, either. Research hasn't shown that they consistently keep mice out of buildings.

If you've been looking into smells that drive mice away, it's worth knowing the limits of these home remedies before relying on them.

For long-term prevention, concentrate on finding and sealing entry points. Traps can help with mice already inside, provided they're checked regularly.

Opening Up Camp in Spring Without Getting Sick

If you return in spring and find mouse droppings or nesting material, don't reach for the broom or vacuum.

Some rodents, including deer mice, can carry hantaviruses. Disturbing dry droppings or nesting material can release contaminated particles into the air.

How to Clean Up Mouse Droppings Safely

Ventilate the space. Open doors and windows in the cabin, shed, or other enclosed building, then leave the area for at least 30 minutes before cleaning. For vehicles, ventilate for at least 20 minutes.

Wear gloves. Use rubber or disposable gloves when handling contaminated materials.

Wet the droppings and nesting material. Spray thoroughly with an appropriate disinfectant or a freshly prepared solution of one part household bleach to nine parts water.

Wait at least five minutes. If the disinfectant label specifies a longer contact time, follow that instruction.

Wipe up the material. Use paper towels and place contaminated waste in a sealed bag for disposal.

Clean the surrounding surfaces. Disinfect affected hard surfaces and wash your hands thoroughly after removing your gloves.

Never sweep or vacuum dry droppings or nests. Don't mix bleach with other cleaning products.

For more information, read our guide on how to clean up after mice safely.

If you find extensive contamination, large amounts of nesting material, or evidence of rodents in ventilation systems, professional cleanup may be the safer option.

When to Call a Professional for Your Camp

Some entry points are easy to spot and repair. Others are hidden behind siding, under floors, or in areas that are difficult to access.

Consider professional rodent control if you're finding droppings in multiple rooms, chewed electrical wiring, or nests tucked into insulation and wall cavities. If mice keep coming back despite trapping, or you're dealing with the same problem every fall and spring, there may be entry points you've missed. A professional inspection can help locate openings that are difficult to find, reach, or seal on your own.

Anchor Pest Services can inspect the property, look for rodent activity, and recommend exclusion work to address accessible entry points.

Depending on the conditions and treatment plan, exterior tamper-resistant bait stations may also be appropriate.

For seasonal property owners, arranging an inspection before closing up gives you time to deal with problems rather than discovering them months later.

Anchor provides Lakes Region pest control, including service through our Bristol branch, as well as Sunapee pest control for properties around Lake Sunapee.

Closing up for the season? Book an exclusion visit before you leave, or call (603) 785-0118 to discuss your property.

FAQs

Is It Common for Campers to Get Mice in Winter?

Yes. Campers offer shelter from the cold, particularly when they're parked for months without regular use. Gaps around plumbing, wiring, and the underbelly can give mice access to the interior.

Do Dryer Sheets Keep Mice Out of Campers?

Not reliably. Dryer sheets lose their scent over time, and mice can still enter through unsealed openings. Checking for gaps and removing food are much more effective ways to prepare a camper for winter storage.

What Smell Do Mice Hate the Most?

Peppermint oil and other strong scents are often suggested as mouse repellents, but none provides dependable long-term protection. A strong smell won't stop a mouse from entering through an opening in the camper or building.

What Is the 5-Day Rule With Mice?

The five-day rule is an informal trapping guideline. If several days pass without a catch or fresh signs of activity, you may have removed the mice that were present. It doesn't mean the building is mouse-proof or that new mice can't get inside.

How Small a Hole Can a Mouse Get Through?

A mouse can squeeze through a gap about a quarter of an inch wide, roughly the width of a pencil. Check around doors, utility lines, vents, and foundation joints for openings that size or larger.

Should I Leave the Heat On at Camp to Keep Mice Away?

No. Heating the building won't keep mice out. They can shelter in heated or unheated spaces, so focus on sealing openings and removing food and nesting materials.

Is It Safe to Clean Mouse Droppings at Camp in Spring?

Small amounts of droppings can generally be cleaned safely with proper precautions. Ventilate the space, wear gloves, wet the droppings with disinfectant, and wipe them up. Avoid sweeping or vacuuming dry droppings, and consider professional cleanup if contamination is extensive.

If you've had mice before or you're finding signs of activity while closing up, Anchor Pest Services can help identify the problem and recommend the next steps.

Our rodent control services address existing activity and help reduce the entry points that allow rodents indoors.

Call (603) 785-0118 or book an exclusion visit before you close up for winter.