Opened Your Cabin After Winter and Found Mice?

Why This Happens Every Spring

Here's the thing about a vacant cabin in Tahoe. From October through March, you've got heavy snow, freezing temperatures, and an empty, heated house. To a deer mouse, that's a five-star hotel.

Empty homes are the highest-risk homes up here — see our second-home rodent protection in South Lake Tahoe before the first snow.

They get in through gaps you didn't know existed — around the dryer vent, under the garage door, where the plumbing enters through the foundation, gaps in the roofline. A deer mouse needs a hole the size of a nickel. Your cabin has dozens of spots that size, minimum.

And once they're in, a vacant house is perfect. No noise. No movement. No one opening drawers or slamming doors. They nest, they breed, and by May you've got a full population. A single pair of mice produces 60+ offspring in a year with a 3-week gestation. Six months of vacancy is plenty of time.

This is the reality of second-home ownership at 6,225 feet. The mice don't break in. They just walk in through gaps that were always there.

Your May Walkthrough: What to Check

Before you start cleaning, do a full walkthrough. Open every door, every drawer, every closet. Here's what you're looking for:

H3: Droppings

Check kitchen drawers, pantry shelves, under the sink, along baseboards, on top of the water heater, and in the garage. Deer mouse droppings are about the size of a grain of rice with pointed ends. Fresh ones are dark. If they've been sitting all winter, they'll be gray and dried out — which means higher dust risk during cleanup. More on that below.

H3: Nests

Look in quiet, undisturbed spots — linen closets, under beds, behind stored furniture, inside the barbecue grill cover, in the attic access. Deer mouse nests are balls of shredded material: insulation, paper, fabric, dried grass. If you find a nest, there's (or was) a breeding population nearby.

H3: Chewed Items

Check pantry food, paper goods, soap bars, candles, wiring on stored electronics, and anything soft. Mice chew constantly — their teeth grow 4 to 5 inches a year and they have to file them down. If they've been chewing on electrical cords or PEX lines, that's damage you need to know about before you turn everything back on.

H3: The Smell

A musty, ammonia-like odor — especially in closed-up rooms, the attic, or the crawlspace — means concentrated mouse urine. The stronger it is, the longer they've been there and the more cleanup you'll need.

H3: Dead Mice

Check traps if you left any set. Check behind the water heater, under the fridge, in the corners of the garage. If you used poison before you left (please don't do this again), check wall voids for the smell of decomposition.

How to Clean Up Safely

This is the important part. Deer mice carry hantavirus, and after a winter of vacancy, those droppings have been drying out for months. Dried droppings turn to dust. Dust gets airborne. You breathe it in. That's the exposure risk.

Do NOT sweep. Do NOT vacuum with a regular vacuum. Both send contaminated dust into the air.

Here's the safe protocol:

1. Ventilate first. Open all the doors and windows. Let the cabin air out for at least 30 minutes before you start cleaning. After months closed up, the air inside is stale and full of dust.

1. Gear up. N95 mask or better, rubber gloves. Non-negotiable.

1. Wet everything down. Spray all droppings, nests, and contaminated areas with disinfectant or a bleach solution (1 part bleach to 10 parts water). Soak it thoroughly. Wait at least 5 minutes. The liquid keeps dust down and kills the virus.

1. Wipe, don't sweep. Pick up the soaked material with paper towels. Wipe up all the liquid.

1. Double-bag and toss. Seal everything in plastic bags, then bag it again. Outdoor trash.

1. Mop hard floors with disinfectant. Steam clean or shampoo carpets.

1. Wash your clothes in hot water, separately. Wash your hands with soap and warm water.

1. Throw away contaminated food. If mice got into the pantry, anything in open or chewed packaging goes in the trash. Don't try to salvage it.

Seal It Before Next Winter — That's the Real Fix

Here's the part most cabin owners skip, and it's why the same thing happens every May.

Cleaning up the mess doesn't stop the next wave. The gaps are still there. The mice are still outside. Come October, they'll walk right back in.

What you need is exclusion — sealing every entry point before the snow flies. Here's the priority list:

• Dryer vent — install a proper vent cover with a damper, not just an open flap
• Garage door — check the weather seal along the bottom and sides
• Plumbing and utility penetrations — seal around every pipe and wire entering the house with steel wool and construction-grade sealant
• Roofline and eaves — metal flashing over gaps where the roof meets the wall
• Crawlspace vents — galvanized steel mesh, not just the original screens
• Foundation gaps — cement or sealant around water lines and sewer penetrations

We do this as part of our exclusion service — starting at $349, we go through the entire house and seal everything we find. For a cabin that sits empty all winter, it's the single best investment you can make. One exclusion job beats five years of spring cleanups.

The Bottom Line

Finding mice in your cabin every spring isn't bad luck. It's a house with gaps sitting empty through a Tahoe winter. The cleanup is annoying but manageable — just do it safely. The real fix is sealing the house before the snow comes.

Opening your cabin this spring to a mouse problem? Give us a call at (530) 203-0122. We'll come out for a free inspection, clean up safely, and seal the place up before next winter.