Will Pouring Bleach Down Drain Kill Cockroaches? | Information and Facts

Bleach is a very popular all-purpose cleaner and is readily available. No wonder many people also use it to kill household pests such as cockroaches.

Bleach may be effective in killing roaches, but it does not necessarily mean that it is the correct way. There are lots of consequences in using it to get rid of cockroaches.

Will pouring bleach down a drain kill cockroaches? Bleach can kill roaches in drains, but it does not automatically solve the problem. It is a very effective disinfectant and a household cleaner. Bleach has an active ingredient that can kill bacteria, but it also poses a health risk to humans and pets if not used properly.

Bleach is not expensive, and you can easily buy it online or in grocery stores. There are also three types of bleach – bleaching powder, oxygen bleach, and the most common, chlorine bleach.

In this article, you will learn the risks of using bleach in killing cockroaches, along with some of the better options.

What Do Sewer Roaches Look Like? 

What Do Sewer Roaches Look Like

Sewer roaches are American cockroaches, which are known for foraging from sewers. Also known as palmetto bugs or waterbugs, this roach species is also common in storm drains, steam tunnels, water meter boxes, zoos, and animal-rearing facilities, as well as in the ground floor areas of commercial buildings.

Scientifically known as Periplaneta Americana, adult sewer roaches are reddish-brown with a pale brown, tan, or yellow band outlining their pronotum.

They can grow between 1½ and 2 inches (38 and 50.8 mm.) long. The wings of the males can extend from 4-8 mm long, which makes them longer than the females.

Can Cockroaches Enter Through Drain?

Cockroaches can enter through floor drains in your kitchen and bathroom. Although this mostly happens in restaurants and commercial buildings at night, roaches can also maneuver their way in residential homes, especially when the drains are dry or when the water traps have dried out or not functioning at all. 

What Smells Keep Roaches Away?

What Smells Keep Roaches Away

Roaches are dirty insects, but there are also some scents that they hate. A study concluded that cockroaches hate the scent of some essential oils.

Therefore, these plant-based oils can be great alternatives to conventional insecticides. Here are some essential oils and smelly household items that can repel roaches:

  • Basil essential oil
  • Cedar essential oil
  • Eucalyptus essential oil
  • Lavender essential oil
  • Mint essential oil
  • Oregano essential oil
  • Peppermint essential oil
  • Rosemary essential oil
  • Bleach
  • Coffee grounds
  • Garlic powder
  • White vinegar


The efficacy of using essential oils to repel roaches depends on the severity of the problem and how you apply them. In most cases, you should spray them on contact and repeatedly.

Also, some of them may be harmful to children and pets. For safety purposes, always read product labels carefully before using them.

What Sounds Do Cockroaches Hate?

Cockroaches hate loud sounds such as stomping of feet, slamming of doors, and sudden clapping. Doing these things can alert other roaches around, and you can see them running and trying to hide.

But contrary to some beliefs, a study concluded that commercial ultrasonic devices are not that effective in repelling cockroaches.

Why Do I Have Roaches in My Clean House?

Why Do I Have Roaches in My Clean House

You have roaches in your house despite being clean because these creepy crawlers are not only attracted to dirt but moisture as well. They entered your house in search of food, water, and shelter.

This is also why you are most likely to see them in kitchens and bathrooms, especially if you have clogged drains.

What Season Do Roaches Come Out the Most?

Roaches are not seasonal pests, which is why you can see them any time of the year. But since they are cold-blooded creatures, they come out mostly during hotter months.

Summer is considered cockroach season, but it can last until the spring months. They will decrease in the fall and are almost gone in the winter.

Should You Pour Borax Down the Drain to Kill Roaches?

Should You Pour Borax Down the Drain to Kill Roaches

You should not pour borax on your drain to kill roaches, but you can use boric acid. Scientifically speaking, borax and boric acid are both borates but not of the same formula. Also known as sodium borate or sodium tetraborate, borax is a white powdery substance that is generally used as an effective cleaning agent.

Borax was originally registered as an insecticide, but the U.S. Environmental Protection Agency (EPA) only allowed it for a year. This is because the agency learned that prolonged exposure to borax dust poses health risks to humans. This is why you should not use borax to kill roaches, especially in your drains.

Meanwhile, boric acid is widely accepted as an active ingredient in household cleaning products and insecticides. This is because insects such as cockroaches will die if they eat or ingest boric acid.

Once roaches have direct contact with boric acid, they will get stuck, and their bodies will be damaged, so they will eat it. 

Does Bleach Kill Cockroaches?

Does Bleach Kill Cockroaches

Bleach kills cockroaches, but there is a catch. To start with, bleach contains sodium hypochlorite (NaOCl), a chemical compound that is used in disinfecting surfaces.

Bleach products should have an EPA registration number before you can use them as pesticides. Otherwise, they should only be used as a disinfectant.

However, it does not necessarily mean you should solely rely on bleach in getting rid of cockroaches. Unlike boric acid, bleach does not stick with roaches, which means that these creepy creatures will only die when they get drowned by bleach or when they ingest it. Bleach may also not be effective in killing roach eggs.

Bleach is also not safe if not used correctly. Mixing it with acids, ammonia, or other cleaning chemicals can cause health problems such as chest pain and coughing.

This can happen if you are exposed to the toxic gasses released by the mixture. Mixing bleach with water is safer but is less effective in killing roaches.

Do Roaches Hate the Smell of Bleach?

Roaches hate the smell of bleach because of its very strong smell. Hence, cockroaches are very likely to avoid bleach. Therefore, they are unlikely to ingest it.

This is another major reason why bleach is not a reliable strategy in killing them. Needless to say, you cannot also use bleach as bait to trap roaches.

How Fast Does Bleach Kill Cockroaches?

Technically speaking, bleach can kill cockroaches very fast. There is no scientific study on how long before roaches can get killed after ingesting it.

Nevertheless, the strong chemical reaction of bleach is enough to kill roaches instantly. But again, the challenge is how you can force them to get in contact with bleach. 

How Do I Get Rid of Roaches in My Drains?

Getting rid of roaches in your drains can be very challenging. Drains may not be permanent hiding places for cockroaches, but they will use them to enter your house, especially to kitchens and bathrooms.

So, to help you out, here are some strategies on how you can clear out cockroaches from your drains effectively:

1. Pour Bleach 

Bleach does not only kill roaches in drains, but it also disinfects the area. But aside from posing health risks, bleach is also corrosive and can damage your drain pipes.

Since bleach is usually readily available in your home, you can use it as an immediate and temporary solution. Be very careful and don’t use it frequently.

2. Pour Baking Soda Mixed With Sugar

Baking soda alone can kill roaches, but just like bleach, they have to digest it first. Adding sugar to baking soda will work well as bait, but the mixture is not safe for children and pests.

Baking soda with sugar is an effective roach killer, but not all roaches in the drain will fall on this trap. It should also be applied repeatedly.

3. Pour Boiling Water

Boiling water does not only kill adult roaches but also their nymphs and eggs. But then, roaches should be soaked into the hot water for a few minutes before they can get killed.

To make it work, pour boiling water into the drain continuously. If the water is no longer hot enough to kill them, they will just crawl away and escape.

4. Apply Diatomaceous Earth (DE)

A scientific study concluded that Diatomaceous earth (DE) is very effective in killing cockroaches in contact. DE kills cockroaches by breaking down the waxy oil that protects their exoskeletons. Note, however, that DE only works better if your drain is dry. If your drain is wet, DE will still work once the drain dries out.

5. Sprinkle Boric Acid 

As compared to the ones mentioned above, boric acid is the safest and the most effective way in getting rid of roaches in drains. Cockroaches that get in contact with boric acid will groom themselves and will die once they eat it. To attract roaches, add sugar to the boric acid before you sprinkle it into your drains. 

6. Place Sticky Traps With Bait

Odorless and non-toxic sticky traps with bait such as Black Flag Roach Motel Insect Trap kill cockroaches effectively. Place them around the drains before sleeping and check them in the morning. The best thing about this product is that the trap is a box, which means you don’t need to look at the trapped roaches. 

What Is the Best Repellent for Roaches?

Truth to be told, there is no single best repellent for roaches since it depends on various factors such as how many roaches there are, their hiding places, and the application method.

Aside from the strategies mentioned above, below are some other techniques that can help repel cockroaches, especially in hidden areas.

1. Use a Vacuum Cleaner

Vacuuming roaches may not kill all the roaches but can surely repel them. Once you turn it on, roaches will be disturbed and will crawl away from their hotspot. Using a vacuum cleaner also helps you prepare for your other control methods.

2. Turn On the Fans

Moving air repels cockroaches, so turn on the electric fans and exhaust fans in the kitchen and bathroom after taking a bath. This also helps reduce moisture, which attracts roaches. Just don’t forget to turn them off if you leave the house.

3. Turn the Lights On

Roaches are afraid of bright lights. Once you suddenly turn on the lights in the kitchen at night, you are likely to see some cockroaches crawling as fast as they can. In doing so, you will have an idea where they could be hiding in the day.

4. Use Aerosol Sprays

Aerosol sprays such as Raid Ant and Roach Killer don’t only kill roaches on contact but also repel those that are near the area. However, don’t spray near your food storage and painted surfaces. Read labels carefully before using.

How Do I Get Rid of Roaches Permanently?

Getting rid of roaches permanently is almost impossible since they are most active at night and will also enter clean houses.

Nonetheless, there are two things you can do – don’t give them what they need inside your house and block all their possible entry points. Here are some simple things you can do:

  • Empty your indoor and outdoor trash cans frequently, and cover them properly.
  • Wash the dishes immediately after eating, and clean the table thoroughly.
  • Keep your food in the refrigerator or sealed containers.
  • Scan your food items and groceries for roach eggs before storing them.
  • Keep your kitchen free of food scraps and other potential food sources of roaches.
  • Feed your pets outside the house and clean their bowls afterward.
  • To help reduce moisture, place a pan under your refrigerator to collect water and empty it regularly.

Tips to Help Prevent Cockroach Infestations in Your Drains

Preventing a cockroach infestation in your drains can be tricky since these disgusting pests can easily populate your sewer system. From there, they can crawl through the pipes and enter your house through your drains without your knowledge. To help you avoid this from happening, here are some useful tips:

  • Free your kitchen drain from food debris that can attract roaches.
  • To make sure your drain pipes don’t run dry, pour at least 2 cups of water daily if you are not using them regularly.
  • Check your drain pipes and repair or replace the leaky ones.
  • Fix or replace leaky faucets that can cause standing water.


Cockroaches will try everything to enter your home not only through the drains but also through tiny spaces that they can crawl into. While all the tips above are effective, roaches will keep on coming back.

Therefore, the key to eradicating them is through regular checking, consistent sanitation, and a truckload of patience.

List of Sources


American cockroach

Cockroach Biology and Management

Least Toxic Methods of Cockroach Control

Lack of Repellency of Three Commercial Ultrasonic Devices to the German Cockroach (Blattodea: Blattellidae)