Cockroaches are present in the UK. While often associated with warmer climates, several species have established populations. They are more common than many realize, especially in heated indoor environments. These pests adapt to human dwellings, concerning residential and commercial properties.
Cockroach Species Found in the UK
The German cockroach (Blattella germanica) is the most common species in the UK. This light tan insect, 10-15mm long, has two distinct dark parallel stripes on its pronotum. They have wings but rarely fly, preferring to run quickly.
Another prevalent species is the Oriental cockroach (Blatta orientalis), often called the “black cockroach” or “water bug.” Larger and darker than German cockroaches, they are 20-30mm long with a dark brown to black, glossy exoskeleton. Males have wings covering most of their abdomen, but females have reduced wing buds; neither sex can fly. Oriental cockroaches are slower than their German counterparts.
The American cockroach (Periplaneta americana) is also found in the UK, though less common domestically than German and Oriental species. It is the largest common pest cockroach, 30-50mm. American cockroaches are reddish-brown with a distinctive yellow border on the pronotum. Both sexes have fully developed wings and can fly short distances, especially in warm conditions. The less common brown-banded cockroach (Supella longipalpa) is smaller (10-15mm) with light or yellowish bands across its abdomen.
Where UK Cockroaches Live and Enter
UK cockroaches primarily inhabit indoors, as the outdoor climate is too cold for year-round survival. They seek warm, dark, humid locations with easy access to food and water. Common indoor habitats include kitchens, bathrooms, basements, and utility areas, around pipes, stoves, and sinks. They are also found in commercial food establishments, boiler rooms, and heating ducts of large buildings.
Cockroaches enter buildings through various pathways, exploiting flattened bodies to squeeze through small openings. Common entry points include cracks and crevices in foundations, walls, and floors, around water/waste pipes and electrical cables. They also gain access through drains, refuse chutes, and vents. Infestations often spread from neighboring properties, especially in multi-occupancy buildings like flats, where voids provide routes between units. Cockroaches or their egg cases can be inadvertently introduced through infested items like groceries, packaging, second-hand goods, or luggage.
Indicators of Cockroach Activity
Cockroach droppings are a common sign of presence. Their form varies by species and size. Small cockroaches, like the German, leave tiny black specks resembling coffee or pepper. Larger species, such as American or Oriental, produce cylindrical, dark brown or black droppings, sometimes with ridges. Droppings are found where cockroaches feed or hide: inside cabinets, along baseboards, or behind appliances.
Smear marks are irregular brown stains left by cockroaches crawling across surfaces, especially in moist areas. They are found on horizontal surfaces and at wall-floor junctions.
Cockroaches shed their exoskeletons, known as shed skins or exuviae, as they grow. These light brown, hollow, papery skins are often discovered near hiding places or high activity areas. Multiple shed skins suggest a significant or ongoing infestation.
Egg casings, called oothecae, are a clear sign of reproduction. These protective capsules contain multiple eggs and vary by species; German oothecae are light brown and capsule-like, Oriental oothecae are darker and more inflated.
A distinct, often musty odor can become noticeable, particularly with a large or established infestation. While primarily nocturnal, frequent daytime sightings often indicate a substantial population, forced out of hiding due to overcrowding or lack of resources.