How to Tell If You Have Cockroaches
Cockroaches are among the most secretive household pests. They are nocturnal, fast-moving, and hide in cracks and crevices during the day — which means an infestation can develop significantly before you notice it.
In the UK, the two species most commonly found in homes are the German cockroach (Blattella germanica), which prefers warm, humid indoor environments like kitchens and bathrooms, and the Oriental cockroach (Blatta orientalis), which is often found in cooler, damper areas like basements and drains.
Cockroach Droppings
Cockroach droppings look like small, dark specks — similar to ground black pepper or coffee grounds. German cockroach droppings often appear as dark smears or streaks near harbourage areas.
Check inside kitchen drawers, behind the fridge, under the oven, around boiler cupboards, along pipe runs, and inside any warm, dark cupboards. A concentration of droppings in a particular area indicates a nearby harbourage point.
Egg Cases (Oothecae)
Cockroach egg cases are small, dark brown, ridged capsules — roughly 8mm long for German cockroaches, larger for Oriental cockroaches. Each German cockroach ootheca contains 30–40 eggs.
Finding egg cases, whether empty or full, is a strong indicator of breeding activity. Look in warm, hidden spots near food and water sources — behind appliances, inside cabinet hinges, under sinks, and along pipe casings.
Musty or Unpleasant Smell
Cockroaches produce a distinctive, oily, musty odour that becomes more pronounced as the infestation grows. The smell comes from pheromones they use to communicate and from their droppings.
If you notice an unexplained musty smell in the kitchen or bathroom — particularly in cupboards or around appliances — cockroaches may be the cause.
Shed Skins
Cockroaches moult several times as they grow from nymph to adult, leaving behind translucent, light-brown casings. Finding shed skins near harbourage areas confirms that cockroaches are not just passing through — they are breeding in your property.
Smear Marks
In areas with available water, cockroaches leave irregular brown smear marks on walls, surfaces, and along their travel routes. These are most visible around sinks, drains, and on light-coloured walls behind appliances.
Seeing Cockroaches During the Day
Cockroaches are nocturnal. If you are seeing them during the day — even just one — it is a strong indicator that the harbourage is overcrowded and the infestation is significant. Daytime sightings mean there are far more cockroaches hiding than the ones you can see.
If you turn on a kitchen light at night and see cockroaches scattering, that also confirms an active infestation.
Where to Check for Cockroaches
Cockroaches need warmth, moisture, and food. Focus your inspection on these areas:
- Behind and under the fridge, oven, and dishwasher.
- Inside kitchen cupboards — check corners, hinges, and pipe entry points.
- Around and under the kitchen and bathroom sinks.
- Boiler cupboards and hot water cylinder spaces.
- Along pipe runs and behind boxing or panels that conceal pipework.
- Inside electrical appliances — German cockroaches are known to harbour in microwaves, coffee machines, and fridge motors.
- Drains and waste pipes — Oriental cockroaches often enter via the drainage system.
When to Get a Professional Inspection
If you have found droppings, egg cases, or have seen cockroaches — even once — professional treatment is strongly recommended. Cockroaches breed rapidly, and over-the-counter products rarely reach the hidden harbourage sites where they live and breed.
A professional cockroach treatment will target harbourage areas with methods not available to the public. At BuzzKill, inspections are free with no obligation. Book your inspection today.
Need professional help? BuzzKill offers fast, reliable cockroach control services across London and Essex.