The signs of a rat infestation are droppings that are dark, roughly 15 to 20mm long and tapered at one or both ends, scratching or gnawing heard at night from under floors or above ceilings, greasy dark smear marks along skirtings and pipe runs, fresh gnaw damage to timber, plastic and cable, shredded nesting material in cupboards and lofts, burrow holes in banks or under outbuildings, and a sharp ammonia smell in enclosed spaces. Find two or three of those together and you are looking at an active infestation rather than a single rat passing through.
The reason to look for a pattern rather than a single clue is that one piece of evidence almost never tells you what you actually need to know. Droppings on their own might be months old. A noise on its own might be a bird under a ridge tile. What identifies a live problem, and what tells you roughly how many rats there are and how long they have been established, is whether the evidence is fresh, repeating, and following a fixed route. That is the difference between finding something and reading it, and it is what decides how the job is dealt with.
Droppings tell you more than the fact of a rat
Rat droppings are the most reliable single sign, and they are easy to tell apart from mouse droppings once you know the scale. A rat dropping is about 15 to 20mm long, roughly the size of a large grain of rice or an olive stone, dark, and tapered at the ends. A mouse dropping is 3 to 6mm, closer to a grain of rice and far more numerous. That difference is not academic, because the two species are treated as different jobs.
Freshness matters just as much as size. A fresh dropping is dark, soft and slightly glossy. Within a few days it dulls, dries out, goes grey brown and crumbles when pressed with a stick. We've found that most people who call us have been looking at a mix of both without realising, and the fresh ones are the whole story. If you clear an area completely and new droppings appear within two or three days, the infestation is live and currently using that route.
Distribution is the third thing to read. Rats deposit droppings as they travel rather than in one place, so a scattered trail along a wall, behind an appliance or across a loft joist maps the route they are running. A heavy concentration in one spot usually means a harbourage nearby rather than a through route.
The smear marks nearly everyone walks past
Rats have poor eyesight and navigate by touch, running the same route repeatedly with their flank against a solid edge. Grease and dirt from their fur builds up on that edge, leaving a dark, slightly shiny band along skirting boards, the bottom of door frames, pipe runs, joists and the lip of any gap they squeeze through. Smears are the single best evidence that a route is established rather than occasional, because they take repeated journeys to form.
In our experience, a torch held low and raked along the skirting works better than the room's ceiling light because smear marks only show up when light strikes them at a shallow angle. Under an overhead light they vanish into the shadow at the foot of the wall, which is why people who have searched and found nothing are often standing in the middle of an active run.
The same trick works on loft timbers and around the openings in an outbuilding. If you find a smear at a gap, that gap is in use, and it is one of the points that needs closing when the property is proofed against rats coming back.
What you hear, and when you hear it
Rats are most active from dusk and through the night, so noise complaints cluster in the evening and the small hours. The sound is heavier and more deliberate than a mouse, closer to a scrabble or a dragging scratch than a light patter, and gnawing carries as a distinct rhythmic rasp. Because rats travel along structural voids, the noise usually tracks a line, under a floor, along a ceiling, or up inside a stud wall, rather than staying in one spot.
Location narrows it down usefully. Noise low down, under a suspended floor or behind a kitchen unit, points to rats. Noise consistently in the loft with nothing at ground level more often turns out to be mice, squirrels or nesting birds, which are three completely different jobs with different legal considerations. Timing helps too, since squirrels are active in daylight and rats are not.
Gnaw damage, and why it is the expensive sign
Rat incisors grow continuously, so they gnaw constantly to wear them down and will work through timber, plasterboard, lead pipe, plastic waste pipe and cable insulation. Fresh gnawing shows pale, clean material under the surface and leaves coarse shavings; old damage is discoloured and dusty.
This is the sign worth acting on quickly, because gnawed cable and gnawed pipework are how a rat problem turns into an electrical fault or a leak under a floor you cannot see. It is also why the law takes a view. Under the Prevention of Damage by Pests Act 1949, occupiers and owners have a duty to keep premises free of rats and mice, and to notify the local authority where an infestation is substantial.
Outside is usually where the evidence starts around here
This is the part that is specific to where we work, and it is the reason a lot of local rat problems get misread. Much of Romney Marsh is reclaimed land drained by a network of dykes, sewers and watercourses, and those banks are effectively a ready made motorway for rats. From working with clients across Dymchurch, New Romney and Lydd, the pattern we see over and over is that the rats arrive along the dyke bank and settle in outbuildings, decking voids, log stores and compost first, then push into the house later, often when the weather turns. The house itself is frequently in good order.
So the outside signs deserve as much attention as anything indoors. Look for burrow entrances roughly 60 to 90mm across in banks, under sheds and behind retaining walls, usually with a fan of loose soil and a smooth, worn run leading away. Look for flattened runs through long grass and nettles, gnawed feed sacks and bird food, and smears on the frame of a shed door. On the farmland edge around Ashford, Canterbury and the Weald villages there is a predictable autumn push, because harvest and ploughing strip the cover and food out of the fields at the same time and rodents move towards buildings. Calls climb from autumn every year for that reason, which is worth knowing if you are reading this in September.
Once you know the route in, the rest of the picture is about what is holding them there, and food, water and harbourage are almost always the reason rats are drawn to a particular home rather than the one next door.
What is usually a false alarm
Not everything that looks like rats is rats, and it is worth ruling these out before you worry.
- Small dark droppings that turn out to be mice, or in outbuildings, hedgehog or bird droppings.
- Daytime loft activity, which is far more likely to be squirrels or birds.
- A single sighting in the garden with no droppings, smears or damage anywhere, which is often a rat passing through rather than living on the property.
- Rustling in a cavity during high wind, which catches people out on exposed coastal elevations along Dymchurch and Hythe.
- Old, grey, crumbling droppings with nothing fresh, which points to a historic problem that has already gone.
When to call someone
If the evidence is fresh, repeating in the same place, or you have found gnawing on cable or pipework, that is the point to get a professional in rather than starting with shop bought bait. Rats are naturally wary of new objects in their environment, so they will avoid traps and bait for days before touching them, and an amateur treatment that is placed in the wrong spot or lifted too early usually teaches them to avoid it permanently. The British Pest Control Association's guidance on rats is clear that professional treatment is the sensible route for an established infestation, partly for that reason and partly because professional rodenticides are not available to the public.
A proper survey should identify the species, map the runs, find the harbourage and the entry points, and deal with the route in as well as the rats themselves. Treatment without proofing simply resets the clock, which is why every one of our rodent control jobs covers both.
We have been treating rats across Romney Marsh, Folkestone, Hythe, Ashford, Dover and the surrounding villages since 2008, with over twenty years in the trade behind that, and we work on domestic, commercial and industrial sites with a 24 hour emergency response and same day attendance on urgent jobs. If you have found something and you are not sure how to read it, get in touch and we will take a look.
Cinque Ports Pest Control Ltd is a family run business based in Dymchurch, Romney Marsh. We are BPCA members, Kent County Council Trading Standards approved, TrustMark registered, SafeContractor approved and CRRU supporters.
