Cockroaches in a flat are usually found by their signs before the insects themselves: droppings, egg cases, a musty smell and shed skins. They hide in warm, dark voids and move between units through shared walls and pipe chases. A check of the kitchen, bath and connecting spaces tells you whether the problem is in one unit or the building.
Key takeaways
- Droppings that look like ground pepper, and egg cases in corners, are better evidence than a single roach seen in daylight.
- A musty or oily smell in the cupboards is a common sign of a larger population.
- Roaches move through shared pipes and walls, so a problem in one flat can reach the next one.
- A building-wide plan, with the neighbouring units and shared spaces treated together, lasts longer than one flat treated alone.
- Cleaning helps, but it does not reach the eggs and the population inside the voids.
What are the signs to look for?
Droppings, egg cases, shed skins, smears and odour. Each one tells you something different about how long the population has been there.
Cockroach droppings are small, dark and often look like ground pepper. They collect along the edges of cupboards, drawers and the back of the stove. A pile of droppings in one place is a sign that the roaches are living close by. Egg cases are small, brown and capsule-shaped, and they are often tucked in corners or behind appliances.
A musty or oily odour in cupboards or under the sink can mean a large population. Shed skins, which look like pale, empty shells, show the roaches are growing. Smears on shelves and along the back of a drawer are another sign that the insects are moving at night.
Where to check in a flat
The kitchen, the bathroom and the places where the pipes come through the wall. Those are the warmest and most sheltered places.
Open the cupboards under the sink and check the back of the cabinet, the edges of the shelves and the gap behind the fridge. Look at the space behind the stove, the drawer runners and the underside of the counter. Use a flashlight, because roaches shelter in dark gaps that look too small to hold them.
In the bathroom, check the space under the sink, behind the bath panel and around the toilet base. Look at the place where the water pipe enters the wall, because that is often where roaches move between units.
- The cupboards under the sink and the back of each cabinet
- The gap behind the fridge and the back of the stove
- The drawer runners and the underside of the counter
- The bath panel, the toilet base and the pipe entry in the wall
Why do roaches move between flats?
Because the flats share walls, pipes and utility spaces. A roach that leaves one unit by the pipe chase can reach the next unit in a short time.
Roaches follow warmth, moisture and food, and they travel along the spaces that connect rooms. In a building, the pipe chase, the drain line and the gap around a utility entry are the common routes between units. A roach in one flat can be in the flat above or below within a few nights.
This is why one flat treated alone often has the problem return. The treatment works in the unit that was treated, but the neighbour's population is still there, and it moves back in along the same route. A building plan treats the connecting spaces as well.
Is it one flat or the whole building?
A technician can usually tell from the places where the signs are found and from the connecting routes. Signs in a shared pipe chase suggest the building, and signs confined to one kitchen suggest one unit.
If the signs are in one kitchen and nowhere else, and the flat has no shared pipe chase with a neighbour, the problem may be confined to that unit. If the signs are found in the hallway, the laundry, the basement or in more than one unit, the problem is building-wide.
A tenant can help by reporting what is seen in the neighbouring flats, and by asking the building manager whether other tenants have reported the same sign. That information helps the technician plan the visit.
What a building-wide visit involves
Access to the units, a shared schedule and a clear notice to the tenants. The technician treats the kitchens and baths together, and checks the shared spaces.
The building manager or the owner sets the schedule and arranges access to the units and the shared spaces. Tenants receive a notice of the visit and are asked to clear the space under the sinks, bag food and bedding and report any new sightings.
The technician treats the units with activity and their neighbours, and checks the pipe chases, the cellar and the laundry. A follow-up visit checks each treated unit, and the building manager receives a written note on the results and any repair needed.
What can a tenant do between visits?
Keep the kitchen clean, store food in sealed containers and report new signs. Those steps keep the population down and help the follow-up.
Wipe the counters and stove top every night, and wash dishes rather than leaving them in the sink. Store dry food in sealed containers and keep the bin closed. Crumbs and grease are the main food sources for roaches, and removing them is the most effective thing a tenant can do.
Report any new sign to the building manager with the date and place. A sign in a new place is information for the follow-up, and it can show whether the problem has moved.
- Wipe the counters and stove top every night
- Store dry food in sealed containers
- Keep the bin closed and empty it regularly
- Report new signs with the date and place
German and American roaches in a building
The two species behave differently. German roaches breed fast and move through shared spaces, while American roaches are larger and more often found near drains and basements.
German roaches are small and pale, and they are usually found in the kitchen and the bathroom. They breed quickly, and a population can build up within a season in a building with shared walls. Their egg cases are often hidden in cupboards and behind appliances, which is why a sighting in one unit can point to a population that is larger than it appears.
American roaches are much larger and reddish-brown. They are more often found in basements, near floor drains and in utility rooms, and they can be seen moving along the outside of a building at night. Treatment for each species places products in different spaces, so the species is identified before the plan is set.
Keeping a simple sightings log
Write down the date, the time, the room and the number seen. A log shows whether the population is falling or moving.
A tenant or a landlord who keeps a log gives the technician information that cannot be gathered in one visit. A count of three roaches in the kitchen on Monday and none on Friday is a sign the treatment is working. A count that moves from the kitchen to the bathroom is a sign the population is moving.
The log should be kept in one place and shared with the technician at each visit. It does not need to be detailed. A short line for each sighting is enough, and it saves time on the next inspection.
If a neighbour refuses access
The unit that refuses access can keep the problem alive for the units around it. The technician records the refusal and tells the building manager what it means for the rest of the work.
In a shared building, a unit that is not treated can keep sending roaches into its neighbours. The technician cannot enter a home without permission, so the refusal is recorded and the other units are treated as far as access allows. The building manager is told what the refusal means for the plan.
Landlords should check the lease and the local rules before giving any notice of entry. The technician does not give legal advice, but can provide a written note of the refusal for the file.
Why cleaning alone does not clear a population
Because cleaning removes food and shelter but not the eggs and the roaches inside the voids. Treatment is needed to reach those places.
A tenant who cleans thoroughly will notice fewer roaches in the open, but the population lives in the voids behind the appliances, under the sink and inside the walls. Those places are not reached by cleaning. A roach that survives in a void will breed and return to the open once the food is available again.
Cleaning is still important, because it removes the food and water that keep the population fed. The combination of cleaning and treatment, with a follow-up visit, is what clears a building over time.
What to expect from a building-wide follow-up
A check of each treated unit, the shared spaces and the connecting routes, with a written note for the building manager. The follow-up tells the manager whether the plan is working.
The follow-up visit checks each unit that was treated and the shared spaces that were included in the plan. The technician looks at the places where activity was found, checks the monitors and the bait, and notes any new sign. A unit with no new activity is recorded, and one with activity is planned for a further visit.
The building manager receives a written note after each follow-up. The note states what was checked, what was found and what is planned next, so the manager can see the progress of the whole building rather than one unit at a time.
Why a building-wide plan takes several weeks
Because the population must be reduced in each unit and the connecting routes checked, and the eggs and the surviving roaches take time to appear and be caught.
A roach population does not disappear at once. Eggs hatch over time, and the surviving roaches move through the building while the treatment is in place. A plan that is spread over several weeks catches the new generation as it appears, and it allows the building to be checked on a set schedule.
A homeowner or tenant should not expect the problem to be gone after the first visit. The plan describes the expected length of the work, and the follow-up dates are set so the progress can be measured.
Frequently asked questions
Is one roach in daylight a sign of a big problem?
It can be. Roaches are mostly active at night, so a daytime sighting often means the population is large or crowded.
Will my neighbour's roaches come into my flat?
They can, through shared walls and pipe chases. A building plan covers the connecting spaces so the problem is less likely to return.
Do I have to clear my whole flat?
Clear the kitchen, the bathroom and the space under the sinks. The technician will say what else helps on the visit.
How long does it take to clear a building?
Usually several weeks, with a follow-up on each treated unit. The schedule is set when the building plan is agreed.
Sources
This guide is general information for Oneida County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.