How Do Cockroaches Get In? 7 Ways Cockroaches Enter Homes

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Surprise! You have a cockroach infestation. Once you make this unpleasant discovery, it’s natural to feel a little offended. “But my house is so clean,” you may think. “My doors are self-shutting and never left open. My windows are screened. What did I do wrong to stop roaches from getting in?”

It’s not you—it’s them. Cockroaches are common in Arizona; the types you’ll encounter are most likely the German cockroach, the American cockroach, the Turkestan cockroach, the Surinam cockroach, and the Brownbanded cockroach. Regardless of the species, cockroaches are very sneaky about getting into homes and other buildings. Despite best efforts and diligent cleanliness, there are many ways cockroaches end up inside. Here are just a few ways that cockroaches creep into homes—and the measures you can take to stop them from invading.

Keep in mind that these are preventative measures. If you’re seeing more than a handful of roaches, there’s a good chance they’ve moved in somewhere nearby. Skip to the end for more info on dealing with an existing population.

If you live in the Phoenix area and need cockroach control at your home or business, we can help! Click here to get your free estimate. We do general pest control at homes and commercial office spaces and can get rid of the cockroaches at your property.

Corrugated Cardboard and Newspaper

Cockroaches are attracted to paper, and it’s for a very specific reason. They communicate with each other through chemical pheromones that they secrete; paper absorbs this pheromone. Essentially, paper helps cockroaches find one another and organize themselves.

What to Do: Replace all cardboard boxes with plastic bins, and do not take and store cardboard products inside. Do not store any newspaper piles indoors or around the house—recycle it!


Cockroaches are crafty enough to crawl in and out through drains and pipes; this is especially a problem in apartment buildings, where drain pipes are used as highways between apartments. Cockroaches thrive in the Arizona heat (in fact, they hide and do not develop or reproduce at temperatures lower than 45°F) so late spring and summer is the high season to be on guard and monitor your drains.

What to Do: Place stoppers and metal baskets over all sink and shower drains in the house. If there’s a bathroom shower or laundry room sink in your home that is not being used regularly, close it up completely when it’s not in use. Above all, keep all drains squeaky clean!

Cracks in the Foundation and Exterior Walls

Although cockroaches can grow to be quite sizeable, some species can still shimmy through cracks and openings as narrow as 1/16 of an inch wide! This means that any openings in a building’s foundation or exterior walls are an open invitation for roaches. Any other gaps around pipes, windows, vents, etc., will also allow roaches to enter.

What to Do: The best measure against roaches entering through cracks is to seal any gaps you may find with a caulking gun. You can also use steel wool, copper mesh, and weather stripping to seal cracks.

Under Doors

This is one of the most common ports of entry for cockroaches, as some species are attracted to the light coming from inside buildings and the space is often large enough for them to slip through.

What to Do: Change any bulbs near doorways from white light to yellow light, which will curb the attraction. On the doors themselves, you can add door sweeps to the bottom edge that form a seal between the door and the threshold.

Clothing and Baggage

Cockroaches stow themselves away on paper grocery bags, briefcases, purses, backpacks, and other unsuspecting personal items. Sometimes it’s the cockroach’s eggs that end up hitching a ride inside.

What to Do: It’s almost impossible to check everything that enters the house for cockroaches or their eggs, but minimizing paper bag usage and regularly washing your bags can help.

Dry Pet Food

Cockroaches aren’t that picky about what they eat. Your bag of dry puppy chow or cat food may be what is attracting the cockroach invasion.

What to Do: Don’t store pet food in garages or sheds before bringing it into the house. Once it’s inside, be careful to store it in a plastic airtight container rather than its opened packaging.

Seasoned Firewood

If you have an indoor fireplace and regularly bring bundles of cut firewood into the house, beware of cockroaches hitching a ride. Cockroaches can live in and around of wood, too!

What to Do: Bring only enough firewood inside for one fire; don’t store the extra in your indoor living space. Also, try not to leave large stocks of firewood outside for season after season—this creates a potential breeding site for cockroaches.

Dealing with Existing Infestations

Roaches rarely work alone. If you see them scurrying around your yard or find more than an occasional visitor inside, it’s likely there’s a larger population nearby. Dealing with that population first will mean there are fewer pests trying to get into your home. Where they live, what conditions they favor, and how quickly they multiply varies with the species.

A General Approach

Remove or minimize possible food, water and shelter sources around your property. Stay on top of your yard maintenance and check your irrigation system for leaking or over-watering. Make sure your property is treated regularly to deal with any pests already on site and discourage new populations from moving in. Most homes have a few elements that the bugs favor, like irrigation boxes and j-trim, so treating these areas effectively make a wold of difference. This is especially true if you live near a green belt, retention basin, alley, or other area where they can live and breed freely. Our Blue Sky 365 program does that and more.

The Troublemaker

One notorious exception to much of what’s been said here are German Roaches. These are a species of small light brown roaches that often hitch-hike into your home and live in small cracks in kitchen cupboards and appliances. Not only can they be difficult to find and get to, they’re also one of the most prolific breeders and can grow from a baby to a parent in just over a month.

If you suspect you have a German roach infestation, we strongly encourage you to seek professional help in dealing with them. Because of the habits of this species, the nature of most over-the-counter roach solutions, and the need for a more aggressive approach, DIY treatments for German roaches rarely get the job done.

Blue Sky’s German roach treatment protocol achieves a 90%+ reduction in population in just a single treatment, with follow-up visits to ensure the entire population is knocked out. Give us a call at (480) 635-8492 with any questions you have. We serve the entire Phoenix area including Gilbert, Chandler, Mesa, and more! We can also help you get rid of scorpions, wasps, crickets, and more.

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