Call : +1 343-459-6272

We're Here to Assist You

Why Rodents Start Moving Indoors in October: A Recent Job & Some Homeowner Tips

Category: Holiday

Published: October 06, 2026

By Wayne, Owner, Wayne’s Pest Extermination

What I Walked Into

October is when I usually start seeing a noticeable change in rodent calls around the Greater Ottawa area.

As the nights get colder and temperatures start dropping, mice begin looking for warmer, protected places to spend their time. Unfortunately, garages, basements, attics, and wall spaces can give them exactly what they are looking for.

A couple of weeks ago, I heard from a homeowner who had started noticing scratching sounds in the evening.

At first, they weren't even sure it was an animal. The noise was coming from somewhere near the basement ceiling and only lasted for a few seconds at a time.

Then they found a few small droppings near a storage shelf in the basement.

That was when they decided to have it checked.

Once October arrives and the weather changes, those same rodents start looking for better shelter.

The Problem

Mice don't need much space to get into a home.

During my inspection, I found activity along the basement wall near where a utility line entered the house. There were droppings behind some stored boxes and signs that mice had been travelling along the edge of the wall.

Outside, I found a small opening around the utility penetration. It didn't look like much from a distance, but it was enough to give mice a way inside.

There were a couple of other spots that weren't showing activity yet but were worth sealing before they became another way in.

That's one of the biggest things homeowners should understand about rodents in October.

They aren't necessarily coming inside because something suddenly went wrong with the house. The colder weather changes what they're looking for.

A warm basement, garage, attic, or wall cavity offers shelter from the weather, and if they can find food nearby as well, there isn't much reason for them to leave.

The Process

I started by checking the areas where the homeowner had already noticed signs of activity.

In the basement, I moved around some of the stored items and followed the areas where droppings were appearing. I checked along walls, behind shelving, around pipes, and near the utility entry point.

Then I moved outside and worked my way around the home.

I inspected the foundation, utility penetrations, vents, door frames, garage door seals, and other areas where rodents commonly find their way inside.

The opening around the utility line was the main concern, so that needed to be addressed. I also pointed out the other small gaps that could become problems as the weather continued getting colder.

Inside, targeted control measures were placed where the activity had been found.

We also went through the basement storage. Some cardboard boxes were sitting directly against the walls, so I recommended reorganizing those areas and keeping them easier to inspect.

There were also a few food items stored downstairs that needed to be moved into sealed containers.

The goal was to deal with the mice already inside while also making it much harder for more rodents to follow them in.

The Outcome

Over the next few days, the homeowner stopped hearing the scratching sounds that had originally caught their attention.

There were no new droppings around the storage area either.

When I followed up, I checked the basement again and went back over the exterior areas we had identified during the first visit.

The main entry point remained sealed, and there were no fresh signs of activity around the areas that had previously been affected.

The homeowner had also reorganized the basement and moved stored food into proper containers.

What they were most relieved about was catching the problem early.

Instead of going through the winter hearing noises and wondering what was moving around inside the walls, they dealt with it when the first signs appeared.

That's exactly what I recommend during this time of year.

DIY Advice I Shared

Here are a few things I recommend homeowners around the Greater Ottawa area check as the weather gets colder:

1. Walk around the outside of your home. Look for small gaps around the foundation, siding, utility lines, pipes, and other openings.

2. Check your garage door seal. If you can see daylight underneath or around the door when it's closed, it's worth having the seal looked at.

3. Keep food in sealed containers. Pet food, bird seed, dry goods, and other stored foods can attract rodents if they're left in bags or open containers.

4. Keep basement and garage storage organized. Avoid leaving cardboard boxes and clutter pushed tightly against walls where rodent activity can stay hidden.

5. Pay attention to droppings. A few small droppings in a basement or garage shouldn't be ignored, especially if new ones keep appearing.

6. Listen for sounds at night. Scratching or movement in ceilings, walls, or the attic can be one of the first signs that something has moved inside.

These are simple checks, but October is a good time to do them before temperatures drop further.

"It's brighter than before!"

— Megan

Professional Insight

I always tell homeowners that October rodent problems are mostly about opportunity.

As temperatures drop around the Greater Ottawa area, mice start looking for places that offer warmth and protection. A house provides both.

If there's a small opening somewhere around the exterior, they may find it.

Once they're inside, they usually stay close to areas where they can move without being disturbed. Basements, garages, attics, wall cavities, and storage areas give them plenty of cover.

That's why I don't just focus on catching the rodents that are already indoors.

I want to know how they got inside.

If you deal with the mice but leave the entry point open, there's nothing stopping another mouse from using the same route later.

October is one of the better times to check those areas because dealing with small openings now can help prevent a much bigger rodent problem once winter arrives.

Closing Thoughts

October is when rodent activity starts changing around the Greater Ottawa area.

As the weather cools down, mice that have been living outdoors begin looking for warmer places to shelter.

If you're hearing scratching sounds, finding droppings, or noticing signs of activity in your basement, garage, or attic, don't wait until the middle of winter to see whether it gets worse.

Take a look around the property, check the possible entry points, and deal with the early signs while the problem is still small.