Many people living in rental properties such as apartments struggle with cockroach problems.
It is said that "if there is one cockroach, there are more than 100," and some people may feel genuinely frightened by their reproductive capacity.
Even if you manage to eliminate cockroaches after an infestation, there is no guarantee they won't return.
To completely eradicate cockroaches from your home, it is necessary not only to exterminate them but also to seal off their entry points.
By hiring a professional cockroach exterminator, you can have both the extermination and the sealing of entry points handled in a single visit.
This article provides a detailed look at the benefits of hiring a professional cockroach exterminator, the typical cost, and cockroach prevention measures you can take on your own.
If you are thinking about moving into an apartment, wondering whether to hire a professional exterminator, or frustrated that cockroaches keep appearing despite your best efforts, please read on to the end.
What Causes Cockroaches to Appear in Apartments?
When moving into a rental property such as an apartment, many people worry about whether cockroaches will be an issue.
For those living alone or for anyone who dislikes insects, this concern is even greater.
Cockroaches can appear in detached houses as well, but apartments tend to have a reputation for being more prone to infestations.
Here, we explain the causes of cockroach infestations in apartments, broken down by type of problem.
Please use this as a reference to help you avoid properties where cockroaches are likely to appear.
Issues with the Apartment Itself
The following four issues are commonly cited as problems with apartment buildings themselves.
・The building is old
・Wood-frame construction
・A convenience store on the ground floor
・Unsanitary conditions
Apartments that fall into these categories are more likely to experience cockroach infestations.
Older buildings tend to develop cracks and warping in exterior walls and plumbing, and wood-frame structures deteriorate more quickly, creating openings that serve as cockroach entry points.
Cracks and gaps reduce the airtightness of a unit, making it easier for cockroaches to get inside.
In addition, apartments with a convenience store on the ground floor attract cockroaches drawn by the smell of food.
First, check whether the apartment itself has conditions that make it easy for cockroaches to enter.
Issues with the Surrounding Environment
The following five issues are commonly cited as problems with the surrounding environment.
・Utility poles or trees near windows
・Wooded areas or parks with dense vegetation nearby
・Neighboring units in poor condition
・A garbage collection area nearby
・A building under construction nearby
If there is a park with dense vegetation nearby, cockroaches may migrate from it into your building.
They can also climb utility poles and trees to reach upper floors, so caution is warranted.
Additionally, if the apartment's garbage collection area is kept in unsanitary conditions, cockroaches are more likely to breed there.
Issues Inside the Unit
Beyond the apartment building and its surroundings, an unclean unit increases the likelihood of infestation.
The following four issues are commonly cited as indoor problems.
・Living on the ground floor
・Not cleaning or ventilating the unit
・Clutter on the floor
・Plants on the balcony
If your unit contains food scraps that cockroaches can feed on, or many places for them to hide, infestations become more likely.
Do not leave kitchen food waste or cardboard boxes sitting around — dispose of them promptly.
Potted plants on the balcony can also attract cockroaches.
Issues with Entry Points
If cockroaches appear even in a newer, well-maintained unit, the problem may lie with entry points.
The following three issues are commonly cited as problems with entry points.
・Gaps around doors and windows
・Holes or gaps in window screens
・Ventilation openings and pipe holes that connect directly to the unit
Cockroaches are said to be able to squeeze through a gap as small as 2mm.
If there are any gaps around the front door, windows, window frames, or screens, be sure to seal them.
Pay attention to gaps around air conditioner pipes, ventilation openings, and air vents as well.
The Difference Between Professional Exterminators and DIY Cockroach Control
Hiring a professional exterminator gives you access to measures and treatments that are beyond the reach of the average person.
Here, we compare the methods used by professionals versus those available to homeowners.
DIY Cockroach Control Methods
One approach to DIY cockroach control is using commercially available pesticides.
There are several types of pesticide products, each with its own characteristics, which we introduce below.
Bait (Poison Bait)
Bait products mix an insecticidal ingredient into food that cockroaches are attracted to.
By placing them in areas where cockroaches are likely to appear, the mechanism is designed to eliminate not only the cockroaches that eat the bait directly, but also those that consume the excrement of the poisoned cockroaches.
Spray Insecticides
There are many varieties of spray insecticides, and choosing the right one can be confusing.
For cockroach control, insecticides specifically formulated to target cockroaches are most effective.
When purchasing, select a product suited to the pest you are targeting.
Fumigants
Fumigants work by dispersing a vaporized chemical that cockroaches inhale, eliminating them.
While highly effective, they have drawbacks such as leaving a chemical odor in the room, and they cannot be used by people with respiratory conditions.
They are best suited for use before moving in or when cockroaches are present in large numbers.
Sticky Traps
This method involves placing adhesive sheets to capture cockroaches.
Like bait products, they are placed in areas where cockroaches are likely to be found, but the key advantage of sticky traps is that they allow you to reliably collect the cockroach carcasses.
Methods Used by Professional Cockroach Exterminators
Next, we introduce the methods used by professionals.
Compare them with the DIY approaches described above.
Extermination Using Commercial-Grade Bait
The current industry standard is extermination using bait products. Spraying chemical agents was previously common, but concerns about health effects on humans led to a shift toward bait-based methods.
The bait used by professionals is commercial-grade and contains specially formulated compounds.
Expert technicians with in-depth knowledge of cockroach behavior place the bait in the most effective locations.
Entry Point Sealing
Professional cockroach exterminators do more than simply eliminate existing cockroaches — they also seal entry points.
Since even a successful extermination will lead to a recurrence if entry points remain open, professionals use specialized putty and wire mesh to thoroughly close off every gap.
Placing bait and sealing entry points together form the foundation of a professional cockroach extermination service.
Three Benefits of Hiring a Professional Cockroach Exterminator for Your Apartment
Even with diligent prevention efforts, cockroaches can still appear.
Here, we introduce the main benefits of hiring a professional exterminator.
Cockroaches in Hard-to-Reach Areas Can Be Eliminated
When a cockroach is spotted in the room, most people's instinct is to grab an insecticide spray.
However, cockroaches move fast and can easily escape.
Once they hide in hard-to-reach places such as under appliances, it becomes very difficult to find them on your own.
If left alone, they may reappear or reproduce and multiply.
Professional exterminators have thorough knowledge of cockroach habits and characteristics, enabling them to reliably locate and eliminate even hidden cockroaches.
Effective Extermination Tailored to Cockroach Behavior
Cockroach control products such as bait and fumigants will not deliver their full effect unless placed in the right locations.
Professional exterminators use commercial-grade products in the optimal manner, which means you can expect a significantly higher level of effectiveness.
Prevention of Future Infestations and Recurrence
Professionals do more than eliminate existing cockroaches — they also take steps to prevent future infestations.
Whenever cockroaches appear, there is always an entry point or an attracting factor behind the problem.
Professional exterminators identify the root cause and implement measures to prevent recurrence.
They will also seal areas that are difficult for non-professionals to address, such as cracks in exterior walls and gaps around drain pipes, using putty and wire mesh.
Typical Cost of Hiring a Cockroach Exterminator for an Apartment
How much does it typically cost to hire a professional cockroach exterminator?
The cost of cockroach extermination in apartments and condominiums varies depending on the number of rooms and the floor area.
Approximate price ranges are as follows.
・Studio to 1K: ¥12,000–¥15,000
・1DK to 2K: ¥13,000–¥19,000
・1LDK to 2DK: ¥15,000–¥20,000
・2LDK, 3K, 3DK: ¥20,000–¥25,000
・3LDK, 4K, 4DK: ¥25,000–¥31,000
・4LDK: ¥30,000–¥32,000
Pricing plans vary by provider, so contact the exterminator in advance for an accurate quote.
Three Things to Confirm Before Hiring a Cockroach Exterminator
There are several things you should verify before hiring a professional exterminator.
Check Whether the Landlord or Property Management Company Will Handle It
If you are living in a rental property such as an apartment, you may wonder whether you can ask the landlord or property management company to take care of cockroach extermination.
In principle, cockroach control is the tenant's responsibility, but some management companies may be willing to assist.
Before hiring a professional on your own, it is worth reaching out to your landlord or property manager first.
Consider Whether You Can Handle It Yourself
If you choose to handle cockroach extermination yourself, you will need to use insecticide sprays or fumigants.
Even if you temporarily eliminate cockroaches, the problem will not be resolved at its root unless the entry points are sealed.
For a lasting solution that prevents future infestations, hiring a professional exterminator is recommended.
Confirm the Odor of the Chemical Agents
When hiring a professional exterminator, check in advance whether the chemical agents used will produce any noticeable odor.
Larger units with more rooms or greater floor area will require larger quantities of chemical agents.
Most professionals use odorless agents with a high safety profile, but some providers may use products that do have a smell.
If odor is a concern, be sure to ask the exterminator about this beforehand.
How a Cockroach Exterminator Works in an Apartment
Here is an overview of what to expect when you hire a professional cockroach exterminator.
On-Site Inspection and Estimate
Once a request is received, a technician will first conduct an on-site inspection.
They will thoroughly examine the layout and characteristics of the unit and ask about the extent of the cockroach infestation.
Most exterminators conduct the on-site inspection free of charge and will recommend the most appropriate treatment method and scope of work for your specific unit.
They will then prepare and present a formal estimate, so raise any questions you have at this stage.
Extermination Treatment
Once you agree to the proposed work and estimate and sign a contract, the actual treatment begins.
Depending on the size of the unit, the extermination process typically takes around two hours.
The treatment generally consists of either "chemical-based extermination" alone, or "chemical-based extermination combined with entry point sealing."
After the work is complete, the technician will walk through the treated areas with you before concluding the visit.
Post-Treatment Follow-Up
A professional cockroach extermination service does not end when the work is done.
Exterminators also provide follow-up support after treatment to prevent recurrence.
Some providers offer a warranty period, so be sure to confirm the details after the work is completed.
During the warranty period, follow-up visits are typically provided at no additional charge.
Do not hesitate to contact the exterminator if you have any concerns.
Who Pays for Cockroach Extermination?
When cockroaches appear in a rented apartment, who bears the cost of extermination — the landlord or the tenant — depends on the circumstances.
When the Tenant Is Responsible
If the tenant is the cause of the pest infestation, they may be held liable under the duty of care as a prudent manager.
This duty — known in Japanese law as the "duty of care of a good manager" — requires a level of care that is objectively reasonable and generally expected.
This obligation applies to tenants as well as landlords.
If the cockroach infestation is attributable to the tenant — for example, because the unit is overflowing with garbage — the tenant may be responsible for the extermination costs.
When the Landlord Is Responsible
If the pest infestation stems from the surrounding environment, such as insects entering through a structural defect in the building, the landlord typically bears the extermination costs.
Landlords are legally obligated to provide tenants with a property that is fit for use and enjoyment (for details on landlords' legal obligations in rental management, please refer to the Rental Management Regulations Guide).
If an infestation prevents tenants from living normally, the landlord must take steps to remedy the situation.
That said, even when a professional exterminator is hired, complete elimination is not always guaranteed. If a landlord has taken all reasonable measures available to them, they are unlikely to bear further liability.
Five Points to Consider When Choosing a Cockroach Exterminator for Your Apartment
While a reasonable level of extermination and prevention is possible on your own, severe infestations are best handled by a professional.
Here, we outline the key factors to consider when selecting a cockroach exterminator.
Clear and Thorough Explanation of the Work
An exterminator who explains things carefully is more likely to be trustworthy.
Before hiring, ask about the scope of work, pricing, and after-service support.
It is also reassuring to check the finer details, such as which chemical agents will be used and how long the work will take.
Detailed and Transparent Estimates
When you request a quote, review the estimate carefully.
A provider whose estimate clearly itemizes the work and associated costs is more likely to have a transparent pricing structure with little risk of surprise charges.
Vague or overly general estimates may lead to additional work being added later, resulting in a final cost significantly higher than expected.
Choose a provider whose estimate is as detailed and itemized as possible.
Recurrence Prevention and After-Service Support
Even after extermination, cockroaches can reappear.
Choosing a provider that offers recurrence prevention measures and follow-up support allows you to address future issues with minimal burden.
Ask about the details of after-service support and the length of the warranty period when making your inquiry.
A standard warranty period is typically around one year, during which follow-up visits are usually provided free of charge.
Proven Track Record
Effective cockroach extermination requires selecting a method suited to the species and its characteristics.
Some exterminators specialize in residential properties, while others have more experience in commercial establishments such as restaurants.
It is advisable to verify in advance that the provider has relevant experience matching your specific needs.
A strong track record in commercial settings does not necessarily mean the same level of expertise in residential extermination, so take note.
Positive Reviews and Reputation
Check reviews when selecting a provider.
Feedback from people who have actually used the service can be a valuable reference.
Look beyond extermination results and pay attention to reviews about the technicians' professionalism and attitude — this helps reduce the risk of a poor fit when you make your booking.
How to Seal Cockroach Entry Points
There are also steps you can take on your own before hiring a professional.
Here, we introduce specific measures to prevent cockroaches from entering your home. All of them can be put into practice right away, so give them a try.
Seal Gaps with Draft Tape
Draft tape is designed to fill gaps around window frames, screens, and doors.
Even when windows and doors are fully closed, gaps can form at overlapping rail sections or due to warping from age.
While draft tape is best known as a cold-weather insulation measure, it is also effective at keeping out cockroaches and other insects.
Cockroaches enter through the smallest of openings — around the front door, windows, window frames, the gap between a washing machine drain hose and the floor, and other tight spaces.
Since draft tape is easy to apply even in narrow areas, make use of it throughout your home.
Window screens in particular are prone to fraying and tearing with age, and even a small hole can become an entry point, so pay special attention to these.
Apply Repellent Spray
Cockroaches can sometimes slip inside during the moment your front door is open.
Applying a repellent spray around the door area is an effective way to deter them from approaching in the first place.
Spray-type repellents are convenient and easy to use, making them a recommended option.
However, if your front door has a mail slot built directly into it, a gap is created whenever newspapers or flyers are inserted. Check it regularly and avoid letting mail accumulate.
Install Drain Traps and Drain Covers
Drain openings are connected to the outside and can serve as cockroach entry points.
Installing a drain cover is a reassuring step to prevent cockroaches from entering through the drain.
Drains are generally fitted with a water trap to prevent insects from entering, but flushing a large volume of water at once can drain the trap's water seal.
If the water seal disappears, replenish it by running a small amount of water to restore the trap.
Some apartments may not have drain traps installed, so it is worth checking in advance.
Apply Insect-Proof Sheeting to Ventilation Openings
Ventilation openings have relatively large gaps that make it easy for insects to enter, so it is recommended to apply insect-proof sheeting designed specifically for ventilation covers.
Sheeting made for this purpose maintains good airflow and will not interfere with the ventilation function.
Simply applying it creates a physical barrier against cockroach entry.
Fit a Cap on the Air Conditioner Drain Hose
The drain hose is the tube that carries water produced by an air conditioner's indoor unit to the outside.
Cockroaches can enter the room through the drain hose, so fit a cap on the end to block this route.
Drain hose caps are available at home improvement stores and will not interfere with drainage.
Fill Gaps Around Pipes with Putty
If there are gaps between drain pipes and wall panels under the kitchen sink or bathroom vanity, cockroaches may be using them as entry and exit points.
Fill any gaps around pipes using gap-filling putty.
Eliminating these openings physically blocks a key cockroach entry route.
If you do not have gap-filling putty, tape can serve as a substitute.
Fit a Filter over the Ventilation Fan
When a ventilation fan is not running, cockroaches can enter through its gaps.
This is especially true of propeller-type fans mounted in walls, which have larger gaps and allow easier access from outdoors.
Install a ventilation fan filter of the type that fully covers the opening to address this issue.
While primarily designed to prevent grease buildup, these filters are also effective against cockroaches.
Place Outdoor Pesticide on the Balcony
In apartment buildings and other multi-unit dwellings, cockroaches can travel across balconies from neighboring units.
To prevent them from entering the room, place outdoor-use pesticide products on your balcony as well.
7 Everyday Cockroach Prevention Habits
To keep cockroach populations under control, it is important to make your home an unattractive environment for them on an ongoing basis.
Here are some cockroach prevention habits you can build into your daily routine.
Seal Food Waste Bags Tightly Before Disposing of Them
After cooking, seal food waste securely in a bag before throwing it away.
Using a garbage bin with a lid helps further suppress food odors.
Leaving waste in a sink-side strainer basket or drain catch will attract cockroaches with the smell, so be careful.
Do Not Leave Food on the Floor
Cockroaches have a keen sense of smell and will follow the scent of food to find it.
Onions in particular are said to be a cockroach favorite — their scent is even used in some pesticide formulations.
If you store onions, potatoes, or similar items at room temperature, hang them or keep them off the floor.
Keep the Unit Clean and Tidy
Cleaning regularly and maintaining a tidy home is the foundation of cockroach prevention.
Avoid leaving anything that could serve as food, and minimize potential hiding spots.
Human skin flakes and hair are also nutritional sources for cockroaches, making regular cleaning essential.
Clothing, books, and other items left scattered on the floor create ideal hiding places for cockroaches, so keep the floor clear.
Empty Plant Saucers Regularly
If you grow potted plants on the balcony or indoors, make sure to empty the water saucers regularly rather than letting water accumulate.
A potted plant with standing water in its saucer creates a comfortable environment for cockroaches.
If you enjoy growing plants, consider cultivating herbs alongside them, as cockroaches tend to dislike herbal scents.
Dispose of Cardboard Boxes Promptly
If you frequently shop online, make a habit of disposing of cardboard boxes as soon as possible.
Cardboard boxes — damp, dark, and warm — are an ideal environment for cockroaches to lay their eggs.
The starch-based adhesive used to seal cardboard also serves as a food source for cockroaches.
Discard any boxes you do not intend to use as quickly as possible.
Incorporate Herbal Scents into Your Home
Cockroaches are said to dislike the scents of citrus, mint, clove, and fennel, among others.
Introducing herbal scents that cockroaches find unpleasant is an effective preventive measure.
If using aromatherapy oils, opt for products made with 100% natural ingredients and use them at night when cockroaches are most active.
Cockroaches also dislike dry environments, so using a dehumidifier to keep indoor humidity low adds an extra layer of protection.
Summary
In this article, we have provided a detailed look at the causes of cockroach infestations in apartments, the benefits of hiring a professional exterminator, typical pricing, and how to choose the right provider.
Cockroach control and prevention can be carried out on your own to a certain extent.
Try making use of commercially available pesticides and taking steps to avoid creating conditions that cockroaches find hospitable.
However, if cockroaches continue to appear despite your best efforts, consider reaching out to a professional exterminator.
A professional can deliver effective extermination tailored to the species and its characteristics, as well as take recurrence prevention measures such as sealing entry points.
