Scratching Noises in Your Walls at Night? What Ontario Homes Are Really Hearing (Fall 2026 Guide)

Quick answer: Light, fast scratching or skittering in your walls or ceiling that starts after dark — especially from September onward — is most often mice. Heavier, slower scratching during daylight hours, especially at dawn, usually means squirrels. Either way, the sound means an animal is inside the structure, and in fall the population behind that sound grows weekly. A $95 professional inspection — credited in full when you book treatment — tells you exactly which one you’re dealing with.

Why the Scratching Always Seems to Start in Fall

Every September, the calls start the same way: “We’ve never had a problem before, but now there’s scratching in the wall behind the bed.” That timing isn’t a coincidence. The first run of cool nights — usually mid-September in the GTA, earlier in Barrie and cottage country — pushes mice out of fields and gardens and toward the nearest heated structure. A mouse needs a gap about the width of a dime. Once inside a wall void, it has insulation for nesting, framing to travel, and your kitchen a few metres away.

The sound you hear is the animal moving between the exterior entry point and wherever it’s feeding or nesting. Walls act like amplifiers: a twenty-gram mouse on drywall at 2 a.m. in a silent house can sound like something ten times its size.

Telling Mice From Squirrels (and Everything Else) by Sound

The two clues that matter most are time of day and weight of the sound.

Mice are most active from about an hour after the house goes quiet until just before dawn. The sound is light, fast and scratchy — skittering, scurrying, occasional gnawing that sounds like fast filing. It often moves along a wall horizontally, or up and down near corners where plumbing and wiring give them ladders. If you knock on the wall, it stops instantly — then resumes minutes later.

Squirrels are the opposite schedule: active at dawn and dusk, silent overnight. The sound is heavier — rolling, thumping, sometimes what sounds like a marble dropped on the ceiling. Squirrel noise is usually in the attic or ceiling rather than the walls, because they enter high, through roof vents, soffits and fascia gaps.

Raccoons are heavier still — dragging, thudding, sometimes vocal chirps and growls, almost always attic-level and at night. Bats make a soft rustling or fluttering, concentrated at dusk, usually in attic gable ends. Carpenter ants, surprisingly, are audible too in a quiet room: a faint, dry rustling inside a wall — like cellophane crinkling — as the colony excavates wood.

If it’s after midnight, light and fast, and inside the wall itself rather than above the ceiling: assume mice and act on that assumption. It’s the most common answer by a wide margin, and it’s also the one that compounds fastest — see our complete Ontario mouse field guide for the full biology.

What Not to Do (We See These Mistakes Every October)

Don’t put poison in or near the wall void. A poisoned mouse frequently dies inside the wall, and a decomposing mouse behind drywall produces an odour problem that costs far more to fix than the mouse did. Poison also does nothing about the entry point, so the next mouse arrives within days.

Don’t seal the hole while the animal is inside. If you find the exterior gap and foam it shut at night, you’ve just locked the animal in your wall. Exclusion has an order of operations: treat first, confirm activity has stopped, then seal.

Don’t wait for it to “go away.” A female house mouse can produce a litter of five to eight pups every three weeks, and fall pregnancies are what turn one set of night noises into an established winter population. The gap between “I heard something once” and “we hear them every night” is usually four to six weeks.

What a Professional Visit Actually Looks Like

Every Sani IQ visit starts with a $95 inspection — credited in full when you go ahead with treatment — because the sound tells us that something is inside, not where it’s getting in. Your technician traces the noise to the activity zone, inspects the exterior foundation, vents, garage seals and utility penetrations, and identifies the entry points. Mice are then treated with an exit-first protocol — treat so they die outside, verify, and seal — rather than baiting indefinitely.

A one-time mice treatment starts at $345. For fall noise complaints we usually recommend Complete Mice Protection at $495 — two visits three weeks apart with a 60-day guarantee, which matches the reality that fall mice arrive in waves, not one at a time. And if your street backs onto a ravine, field or construction site, the Mice Protection plan at $895/yr exists precisely because the supply of new mice never really stops — quarterly inspection, exclusion and treatment, with no monthly billing and no initiation fee.

We serve the whole region same-day where the schedule allows — from mice control in Toronto and Vaughan to Whitby and everywhere between.

FAQ

The scratching stopped for a few days. Is it gone? Probably not. Mice shift activity zones as they exploit new food sources or as temperatures change. Silence for a few nights followed by noise in a different wall is the normal pattern of a growing population, not a departing one.

Can I find the entry point myself? Sometimes — check where utilities enter the foundation, garage door corners, and the gap where deck ledgers meet brick. But mice exploit gaps you can’t see from ground level, and in our inspections the entry the homeowner found is rarely the only one.

Why do I hear it in the bedroom wall specifically? You don’t necessarily have mice in that wall — walls carry sound along framing. The bedroom is simply where you’re quiet enough to hear the structure. The activity zone is often the kitchen or an exterior wall nearby.

How fast can you come? Same-day across most of our service area when the schedule allows. Call (705) 302-1887, or get matched to the right treatment in 20 seconds without a phone call.

Is the treatment safe for kids and pets? Yes — we use reduced-risk, Health Canada–registered products and tamper-resistant equipment, and your technician explains everything before treating.