Where Do Roaches Come From? How They Get Into Canadian Homes

Where Do Roaches Come From?

Roaches in your home come from three places: things you carry inside, neighbouring units, and, for a few species, drains, sewers or the outdoors. Once they are in, they stay because your home gives them food, water and shelter, which our guide to what attracts roaches covers in detail. Here are the routes, from the most common to the least.

Groceries and Cardboard Boxes

Groceries and cardboard boxes are one of the most common ways roaches get into a home. The University of Kentucky notes that cockroaches are often introduced in produce boxes, beverage cartons and grocery bags, and Ontario's Southeast Public Health warns that roaches can arrive as egg cases on groceries. Cardboard is a perfect hiding place: Health Canada points out that roaches can chew through paper and cardboard and may lay eggs inside. One German cockroach egg case holds about 30 young (UC IPM), so a single hidden case can start a problem.

Used Furniture

Used furniture brings in roaches and their eggs. Health Canada lists used furniture among the objects roaches hitch a ride on, and UC IPM advises looking for egg cases glued to the undersides of furniture. Brown-banded cockroaches are especially likely to travel this way, because they attach their egg capsules to the undersides of dressers and tables.

Used Appliances

Used appliances are a classic hiding spot for roaches. UC IPM tells inspectors to look for egg cases in refrigerator and other appliance motors, where it is often warm and dark. Montreal public health advises checking electrical appliances, furniture and food for insects before you settle into a new home.

Luggage and Moving

Luggage and moving boxes carry roaches from one home to the next. Penn State Extension notes how hard it is to keep cockroaches from entering homes in boxes, grocery bags and suitcases. A move is a high-risk moment, since you bring in many boxes and pieces of furniture at once. Our guide on how to keep roaches from moving with you explains how to pack and unpack safely.

Neighbouring Apartments

Neighbouring apartments are a major source of roaches in multi-unit buildings. According to the University of Kentucky, German cockroaches often travel between adjoining apartments along utility pipes and wires and inside wall voids, and Health Canada notes that once inside a building, they travel quite easily. Montreal public health found that in 2018, about 3% of households in the city had had cockroaches. If your home is spotless and roaches keep showing up, the source may be next door.

Drains and Sewer Lines

Drains and sewer lines are a route for the larger cockroaches. UC IPM explains that American cockroaches sometimes forage from sewers into the ground floor of buildings, especially when pipes are damaged, screens are missing or the water traps in drains are faulty. Oriental cockroaches can climb up through damaged drain pipes and end up trapped in sinks or tubs. If you find roaches in a sink, tub or floor drain, read our guide on how to stop cockroaches from coming up the drain.

Exterior Gaps

Exterior gaps around doors and windows let some species walk in from outside. The University of Kentucky notes that American and Oriental cockroaches enter through cracks and openings around windows and doors. Roaches need very little room: a UC Berkeley study found that American cockroaches can squeeze their bodies down to about one-tenth of an inch (about 2.5 mm) and slip through slits that size in less than a second.

Where Do Cockroaches Come From, by Species?

Where cockroaches come from depends on the species: some live only indoors, while others live in sewers, basements or the outdoors. Canada's main household species are generally German, brown-banded, American and Oriental, plus wood cockroaches that live outdoors and sometimes wander in. Knowing which one you have tells you which route to close. If you are not sure, start with our cockroach identifier.

German Cockroaches

German cockroaches generally come from inside buildings. They are light brown, about 1.3 cm to 1.6 cm long, with two dark stripes behind the head, and Health Canada notes they have been found in buildings as far north as Nunavut. UC IPM says German cockroaches live and breed entirely indoors, so they almost always arrive in something you brought home or from a neighbouring unit. Inside, they stay close to warmth, moisture and food: kitchens, bathrooms, under sinks and behind fridges, dishwashers and stoves.

Brown-Banded Cockroaches

Brown-banded cockroaches also live only indoors, but they hide in different places. The University of Kentucky notes they are more often found in homes and apartments, often in rooms other than the kitchen and bathroom: high on walls, in closets, behind picture frames and inside furniture. They usually arrive with used furniture, since they glue their egg capsules under dressers and tables.

American Cockroaches

American cockroaches come from sewers, steam tunnels and damp basements. They are among the largest common species, with adults up to about 2 inches (about 5 cm) long (Penn State Extension). The University of Kentucky says they nest in floor drains, sump pumps, pipe chases and laundry areas, and UC IPM notes they are common in sewers and storm drains. In a house, they usually come up through drains or in through basement gaps.

Oriental Cockroaches

Oriental cockroaches come from cool, dark and damp places such as sewers, basements, floor drains and sump pumps. They are usually shiny black or dark brown and, in warmer months, can also live outdoors under leaves and mulch (University of Kentucky). UC IPM notes they may move into buildings at night in search of food, water or mates, and Terminix Canada notes they often get in through gaps in doorways.

Wood Cockroaches

Wood cockroaches come from the outdoors and generally do not infest homes. They live in leaf litter, under logs and in woodpiles, and Penn State Extension notes that they can come in by accident through foundation cracks, on firewood, or after being drawn to porch lights. Orkin Canada describes the Pennsylvania wood cockroach as the most common wood roach in Canada, with males often flying to find mates in May and June. Indoors, wood cockroaches usually dry out and die within a few days and do not breed (Penn State Extension, University of Minnesota Extension), so one in your living room is likely a visitor, not the start of an infestation.

Where Did Cockroaches Originally Come From?

Cockroaches that live in Canadian homes are generally not native to Canada: the main household species were likely carried here by people from Asia and Africa. They spread around the world with trade, and they still travel the same way today, in boxes, bags and furniture.

The German Cockroach's Asian Origin

The German cockroach most likely came from South Asia, despite its name. A study published in the Proceedings of the National Academy of Sciences in 2024 found it is almost identical genetically to Blattella asahinai, a cockroach native to the Bay of Bengal region. According to the University of Western Australia, which took part in the research, there are no known wild populations of German cockroaches: the species is largely domesticated and depends on human buildings to survive.

The American Cockroach's African Origin

The American cockroach likely came from Africa, not America. Animal Diversity Web (University of Michigan) explains that it is not native to North America and was most probably brought over on ships from Africa. It is now found worldwide.

How Trade Spread Cockroaches

Trade spread cockroaches around the world over many centuries. The same 2024 study traced the German cockroach spreading west from eastern India with trade and military activity, then east into Indonesia and later into Europe. From Europe, it then spread worldwide, probably helped by steamships. That is still how roaches move today: hidden in goods and belongings that people carry from place to place.

How Do You Find Where Your Roaches Are Coming From?

Finding where roaches are coming from starts with sticky traps placed along the edges where roaches travel. Traps show you where activity is highest, which points to the hiding spot or entry route.

Sticky Traps

Sticky traps are the best way to detect and monitor cockroaches, according to UC IPM. The University of Kentucky recommends placing them beneath sinks and behind refrigerators, pushed flush against walls and corners, because roaches tend to travel along edges rather than in the open. Check the traps after a few nights: the trap with the most roaches is usually closest to the source.

Hiding Spots to Check

Hiding spots to check are the warm, damp, dark places near food and water. Use a flashlight to look under sinks, behind and under the fridge, stove and dishwasher, inside cabinets, around pipe openings and in floor drains. Look for live roaches, droppings and egg cases.

Matching the Room to the Species

Matching the room to the species narrows down the source quickly:

• Kitchen or bathroom, small light brown roaches: German cockroaches, coming from items you brought in or from a neighbouring unit
• Bedrooms, closets or furniture, small roaches high on walls: brown-banded cockroaches, often from used furniture
• Basement, laundry room or floor drain, large reddish brown roaches: American cockroaches, coming from drains or sewers
• Basement or floor drain, shiny black or dark brown roaches: Oriental cockroaches, coming from drains or gaps under doors
• Near the fireplace or a light in late spring: wood cockroaches, coming from firewood or the outdoors

How Do You Stop Roaches at the Source?

Stopping roaches at the source means closing the route they used: inspect what comes in, seal openings, screen drains and get the building treated if they come from next door. For a complete plan, see our guide to cockroach prevention.

Inspect Items Before They Come In

Inspecting items before they come in stops the most common route. Check grocery and delivery boxes, and unpack them outside or near the door, then recycle the cardboard right away. Look under and inside used furniture and around appliance motors before bringing them in. Store food in sealed glass or plastic containers, since Montreal public health notes that cardboard and paper are not cockroach-proof.

Seal Utility Openings

Sealing utility openings blocks the paths roaches use between units and rooms. Health Canada recommends sealing and caulking all cracks, crevices and pipe openings, and the University of Kentucky notes that plugging openings where pipes or wires pass through walls or floors is especially useful in apartments. Rubber seals under outer doors can also help, according to Montreal public health.

Screen Drains

Screening drains keeps sewer roaches out. Health Canada suggests putting a fine mesh screen over drains, vents and open pipes. Run water in floor drains and rarely used sinks so the water trap stays full, and have damaged drain pipes repaired, since UC IPM notes that American cockroaches can get in through faulty traps and broken pipes.

Keep Firewood Outside

Keeping firewood outside stops wood cockroaches from riding in. Stack it away from the house, and only bring in what you will burn right away, shaking off the logs first. Turning off porch lights at night may also draw fewer wood roaches to your doors in late spring.

Tell Your Landlord

Telling your landlord right away is the most important step if you rent. The Government of Manitoba says tenants should report cockroaches as soon as they suspect them, and that landlords are then generally responsible for making sure units are pest-free. In Montreal, public health advises tenants to send a registered letter if the owner does not act, and to contact the borough (311) if nothing is done within a reasonable time. Roaches that come from neighbouring units need a building-wide approach, so treating your unit alone rarely solves the problem.

When to Call a Pest Control Professional

Calling a pest control professional makes sense when you keep seeing German or brown-banded cockroaches, because these species breed indoors and a single mated female can lead to thousands of roaches in less than a year (University of Kentucky). It also makes sense in apartment buildings, where the Government of Manitoba warns that store-bought chemicals may spread cockroaches to other units. To understand how a few roaches become a real problem, read how a cockroach infestation starts and the signs of a cockroach infestation. Our guide to cockroach pest control explains what professionals do, and you can get a quote from a recommended local exterminator through Pest Agent's referral form. For more guides on roaches, visit the cockroach hub.