Signs of a Cockroach Infestation in Your Home (and What to Do)

Six signs you have a cockroach problem

Most households notice the evidence before the insect. Check behind the fridge, under the sink, inside cabinet hinges and around the gas pipe entry point.

• Droppings that look like ground black pepper (German cockroach) or small dark cylinders (American cockroach).
• Brown smear marks along skirting and cabinet edges in damp areas.
• Egg cases (oothecae) — hard brown capsules about 6–8 mm long, often glued into cracks.
• A musty, oily odour in a closed kitchen cabinet.
• Shed skins near a food source or water source.
• Live cockroaches during the day, which usually means the harbourage is overcrowded.

Why cockroaches matter beyond the nuisance

Cockroaches walk through drains and waste before walking across food surfaces, so they mechanically carry bacteria into kitchens. Their droppings and shed skins are also a well-documented indoor allergen that can aggravate asthma, especially in children. That is the main reason a visible infestation should be treated rather than sprayed over.

Why sprays from the shop rarely fix it

Aerosol sprays kill the cockroaches you can see and scatter the rest deeper into wall voids and appliance motors — a behaviour called flushing. The colony then rebuilds from the egg cases, which are resistant to most contact sprays. Professional treatment uses a gel bait that cockroaches carry back to the harbourage, combined with an insect growth regulator that stops the next generation maturing.

What a professional cockroach treatment involves

• Inspection to locate harbourage points and the moisture source feeding them.
• Targeted gel baiting in cracks, hinges, appliance housings and false ceilings.
• Drain and manhole treatment where American cockroaches are entering.
• A follow-up visit after two to three weeks to catch newly hatched nymphs.
• Proofing advice: sealing gaps, fixing leaks and managing bin hygiene.

How to keep them out afterwards

Fix dripping taps and slow drains, store dry food in sealed containers, empty the kitchen bin nightly, and keep drain covers closed at night. In a building with a shared infestation, treatment works far better when neighbouring flats and the society common areas are treated in the same round.