Signs of Rats in the House: What to Look For
By Henry, Taff Pest Control · Reviewed August 2026
Most people with rats never see one. Rats are cautious, mostly nocturnal, and very good at living a full life inside your walls without an introduction. What they can’t do is avoid leaving evidence, and reading that evidence is most of our job. Here’s what to look for, roughly in the order people usually find it.
The seven signs of rats
1. Droppings. The most reliable sign. Rat droppings are dark, tapered and about the size of a raisin, noticeably bigger than a mouse’s rice-grain pellets. You’ll find them along walls, behind kitchen kickboards, under the sink, in the loft or garage. Fresh ones are dark and soft-looking; old ones grey and crumbly, which tells you whether the activity is current.
2. Noises after dark. Scratching, scurrying or gnawing in the walls, ceilings or under the floor once the house goes quiet. Rats are heavier than mice: more of a purposeful scuttle than a faint rustle. (Loud scampering in the loft during the day points to squirrels instead.)
3. Smear marks. Rats follow the same routes repeatedly, hugging walls, and the grease in their fur leaves grey-black smudges along skirtings, pipes and hole edges. Established smears mean an established problem.
4. Gnawing. Fresh teeth marks on wood, plastic, packaging and, most seriously, cables. Rats’ teeth grow constantly and they gnaw to wear them down. Chewed wiring is the sign that moves a rat job from “soon” to “now”.
5. Burrows and runs outside. Fist-sized holes beside sheds, decking, compost bins or drain covers, and flattened runs worn through grass along fences. Outdoor activity near the house is often the overture to indoor activity.
6. Footprints in the dust. In lofts, cellars and garages, look for four- and five-toed prints and tail drags in dusty patches. An old poacher’s trick: dust a suspect area with flour and check it the next morning.
7. The smell. A stale, musky, ammonia-edged smell that lingers in enclosed spaces: cupboards, voids, the loft hatch. Pets often notice first: a dog or cat suddenly obsessed with one corner of the kitchen is telling you something.
Rat or mouse?
Size of droppings is the quickest tell: raisin versus rice grain. Rats are louder, follow fixed routes and often arrive via drains; mice roam more widely and slip through smaller gaps. There’s a full comparison table on our rodent control page, but quicker: photograph the droppings, WhatsApp them over, and we’ll tell you which you’ve got in a minute.
What to do next, and what not to do
Do: photograph the evidence where it lies, note where and when you hear the noises, and get it looked at while it’s a small job. Rats breed fast, and they look for a way into warm buildings all year round. Early action is genuinely smaller money.
Don’t block the holes yet. It feels productive, but sealing entry points before the inside is dealt with can trap rats in the building, and it destroys the evidence picture that tells us how they’re moving. The proofing comes at the right stage of the job, done properly.
Don’t scatter shop poison. Loose bait is a hazard to pets and wildlife, it kills rats in places you’ll smell for weeks, and a half-poisoned population turns bait-shy, which makes the professional job slower. Our approach is iterative elimination: map the evidence, control with traps leading, and find and close the entry points one by one. Minimum three visits, often more, until the signs stop and stay stopped.
Common questions
I’ve found droppings. Does one rat mean many?
Not always, but rats rarely stay single for long, and by the time droppings are obvious indoors there’s usually more than a lone visitor. The evidence pattern on a first inspection (quantity, freshness, locations) gives a reliable read on numbers.
Do rats come out during the day?
They prefer night, so daytime sightings usually mean either a disturbed nest or pressure on food, both signs of an established population. Daytime loft noise, on the other hand, is more likely squirrels.
What attracts rats to a house?
Food, water, warmth and access: bird feeders, compost, pet food left out, water from dripping outlets, and routes in (defective drains above all in Cardiff’s older streets). Remove the attractions and close the routes, and the house stops being worth their while.
How quickly does a rat problem get worse?
Quickly. A pair can become a colony within a couple of months in good conditions, which is why early evidence matters in any season. The difference between a two-visit and a five-visit job is usually how long the signs were ignored.
Worth reading: where the evidence could belong to either animal, our rat or mouse guide puts the two side by side.
Seen one of the seven signs? Send us a photo of what you’ve found and we’ll give you a straight read on it, and on what it’ll take.