Cockroach Signs: How to Know You Have an Infestation

Seeing one cockroach at night is rarely a one-off. These insects are nocturnal and secretive, so the one you notice is usually a small part of a larger group sheltering out of sight.

The good news is that cockroaches leave a trail. If you know what to look for, you can confirm a problem early and avoid a much bigger one later.

The insect itself

Two species cause most trouble in UK homes and businesses. The German cockroach is small and light brown with two dark stripes behind its head, and it breeds fast in warm kitchens. The oriental cockroach is larger, dark brown to black and shiny, and tends to favour cooler, damper spots such as basements and drains.

Cockroaches run quickly when a light comes on, and can squeeze into gaps that look far too narrow. A sighting in daylight can suggest that the hiding places are crowded. Wings are present on adults but they rarely fly, so what you see is usually a fast runner heading for cover.

Droppings, smears and smells

Droppings from small cockroaches look like ground black pepper or coffee grounds, while those of larger ones are cylindrical. You will find them along edges, in cupboard corners and under appliances. In damp conditions you may also see brownish smears.

A heavy infestation can produce a musty, oily smell that lingers in cupboards and behind units. If your kitchen has started to smell odd for no clear reason, check inside and behind the cabinets.

• Small dark specks like pepper in cupboards and drawers
• Brown smears on walls or near water sources
• A stale, musty smell in a kitchen or utility room
• Shed skins, which are pale and brittle

Egg cases and nighttime sightings

Female cockroaches carry or drop capsule-shaped egg cases, called oothecae. They are small, brown and purse-like, and can hold many eggs. Finding one means breeding is happening nearby.

Go into the kitchen at night, switch the light on suddenly and see what scatters. Sightings around the bin, sink, dishwasher or behind the fridge are classic. A sticky trap placed along a wall can also show whether insects are moving through.

Where they gather

Cockroaches need warmth, moisture and food. Kitchens, bathrooms, utility rooms, behind boilers and around heating pipes are favourites. In shared buildings, flats and takeaways they can move along pipes and ducts between units.

Food businesses, hotels and guest houses should take any sighting seriously, since cockroaches can contaminate food and surfaces. For homes, they can spread bacteria and may worsen allergies and asthma. If anyone has health concerns, speak to a pharmacist or GP.

What to do about it

Tidy food away, fix leaks, empty bins often and clear crumbs and grease. This reduces what they can live on, but rarely removes a settled colony. Cockroaches also tend to travel in with boxes, second-hand appliances and deliveries, so inspect these when they arrive. Over-the-counter sprays can scatter cockroaches into new areas and make the problem harder to treat.

A professional will identify the species, find the harbourages and choose a treatment to suit the property and the people in it. Essex Pest Solutions can inspect homes, rented properties and businesses, and cost depends on the size of the premises and the extent of the problem.

Frequently asked questions