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What to Pour Down Drain to Kill Roaches? [Nothing WORKS, but…]

The American cockroaches, aka, Palmetto bugs are commonly found in the sewer system.

The cockroaches typically come into your home at night by crawling through drain pipes. This is because mostly at night, the drains are not flooded with water.

Here is a miniature representation of what the drain system looks like with cockroaches inside them.

Cockroaches in Drain Pipes and How to Get Rid of them

So technically, you CAN’T get rid of all cockroaches inside your drain pipes, whatever you do.

The sewer system is connected to the entire city, and it is impractical plus harmful for the environment to get rid of these cockroaches. Learn More: Why Do Cockroaches Exist? [HEAL or KILL?].

If anyone who says that pouring XYZ liquid or mixture in your drain will kill roaches is probably misguiding you.

So, the only option is to use drain covers that can stop cockroaches from coming inside your home.

These Anti-cockroach covers should have small holes, which I will explain further below in the article.


To get a temporary fix, you can kill a few roaches near your drain entry points by pouring hot boiling water or a concentrated bleach solution.

White vinegar mixed with baking soda will also kill a few roaches down the drain. Ammonia or concentrated acid cleaners are other good alternatives.

Sometimes it can be challenging to eliminate roach infestation.

The bugs keep reappearing even after successful extermination.

One of the critical reasons for the reinfestation is the poor lookout for the buffer zones. (e.g., drain holes of the sewerage system).

To be successful, you must stop the cockroaches from coming into your house, but you can’t kill all of them inside your drain pipes.

Tired of cockroaches? Invest in only these products and follow the guide to eliminate roaches!

Use these products, and you will be roach free in less than a week.

1. Advion Cockroach Gel Bait (Review)
2. Gentrol IGR Point Source (Review)

Other Products to try:

1. Combat Roach Traps (Easy than gel baits)
2. Hot Shot Foggers (To kill in masses – 95%)
3. Pet Safe Killers (Uses Essential Oils)
4. Ortho Defence Outdoor Roach Killer (Prevent Roaches)

Do Roaches come up through drains?

As an individual who has taken extensive preventive measures against infestations in my home, I was perplexed when I discovered that cockroaches had infested my bathroom and kitchen a few years ago.

Despite my constant search for potential entry points such as cracks, ventilation points, and loose drain covers, I could not identify any obvious sources of entry. My diligent efforts to prevent infestations appeared to be in vain.

However, one day, I was taken by surprise when I personally witnessed the cockroaches exiting through a small sink cover hole.

This experience was illuminating and helped me understand how these creatures possess incredibly flexible bodies despite their seemingly rigid exteriors. Ultimately, this realization allowed me to take the appropriate measures to eliminate the infestation and prevent future occurrences.

Do roaches come up through drains? Yes! Roaches come up through drains, especially at night, by crawling through the drain pipes.

The roaches love to live inside sewerage holes because of the warm moist environment, ample food in the form of filth, and excellent hiding places.

Moreover, Do roaches die when they go down the drain? No, they breed and thrive in these sewer systems. Since roaches can survive underwater for 4-6 hours, they easily survive a gush of water when you flush down the drain.

Solution: Anti Cockroach Drain Covers?

Our washrooms’ default metallic drain covers have large openings, which can easily allow roaches to enter. Given the remarkable ability of these pests to fit through narrow crevices, it is essential to take preventative measures.

To address this issue, we recommend utilizing Anti-water bug drain covers to seal existing openings and prevent bugs and roaches from infiltrating your bathroom or kitchen.

Below is a carefully curated list of the most effective drain covers we recommend. These covers are designed with small holes specifically designed to keep roaches and other pests out, ensuring that your space remains clean, hygienic, and free of infestations.

  1. LEKEYE Steel and Silicone Shower Drain Cover
  2. OXO Good Grips Silicone Drain Cove
  3. Flexible Silicon Drain Cover Large
  4. OXO Good Grips Shower Stall Drain Protector
  5. Drain Defender for Outdoor Drain Fittings

Things you can put in the drain to kill a few roaches

It can be tricky to select an appropriate roach killer that will manage to kill them down the drain.

Time is the most crucial factor that will influence your success in killing roaches down the drain.

You can use these methods any time, but my personal experience suggests that these methods are most influential around midnight.

1. Boiling Water:

Boiling water is an effective and straightforward solution to eradicate roaches that have infested the drain. However, it is important to understand that this method is limited in scope and cannot eliminate the entire roach population in the sewer system.

New roaches may appear in your drain pipes once the existing ones have been eliminated.

When boiling water comes into contact with roaches, it kills them instantly. It is important to note that repeating the process several times may be necessary for optimal results. Additionally, to ensure your safety, it is recommended to use heat-resistant gloves to prevent burns and scalding of the skin.

To achieve the best results, it is necessary to boil approximately 2-3 gallons of water and pour it down the drain instantaneously. It is crucial to avoid interruptions as roaches may sense danger and escape.

After waiting for 10 to 15 minutes, it is recommended to flush the drain with normal water. Following these steps greatly increases the chances of successfully eliminating the roach infestation in your drain.

2. Bleach Solution

Bleach is another excellent alternative to boiling water. Free chlorine is an oxidizing agent that kills roaches and their eggs instantly.

I recommend bleaching tablets over a pre-packed bleach solution. Using bleaching tablets allows you to adjust the concentration of the solution.

To make a solution, take 20 bleaching tablets and mix them in one liter of water. This will give you a very concentrated solution. It is essential to use a freshly prepared solution; otherwise, it will lose its efficacy.

Once the solution is in your hands, pour it inside the drain and wait for 20 minutes.

After that, flush the drain with normal water.

You can also use a bleaching solution if you don’t intend to use tablets. All you have to do is to pour 2 cups of solution and flush it after 20 minutes.

Bleach can be corrosive to drain pipes and porcelain, so flush it with water after 20 minutes. Repeat the process if necessary.

Using boiling water mixed with bleaching tablets gives superior results than either alone.

Again, this method will be able to kill roaches in your drain pipes only.

3. Vinegar and Baking Soda

Vinegar and baking soda are readily available at home and effective for killing roaches but are not superior to bleach.

Mix equal parts of both in a container to use vinegar and baking soda to kill roaches down the drain.

Next, Pour this solution directly into the drain and wait for 5 minutes before you flush normal water over it.

Vinegar is acid and is corrosive to porcelain tiles. Although it can be suitable for old tiles, I do not recommend it for new tiles.

4. Pour Ammonia Down Drain for Roaches

The working principle of ammonia solution is similar to bleach. Both are equally effective at killing roaches down the drain.

The problem with the ammonia solution is its pungent smell, making it less ideal.

For best results, Boil 1 gallon of water and add 2 cups of ammonia solution. Pour it down the drain and wait for the results.

Can Roaches come out of shower drains?

The factor that keeps roaches from coming out of the drain is standing water inside the drain pipes.

The water creates a barrier that cockroaches can’t cross. This is why cockroaches cant come out from the commode.

On the other side shower, kitchen, and other drains lack a water barrier making this route ideal for roaches.

The tiny holes on the drain cover will prevent bathroom and kitchen infestation depending upon the size of the roaches.

Palmetto bugs, including American and Florida wood cockroaches, will usually find it challenging to escape tiny holes on the drain cover.

Still, smokey brown and german cockroaches will quickly come out of shower holes.

The roaches usually come out at the ideal time, around midnight when drains are not used and flooded with water.

Baby palmetto bugs are minor in size and will escape the most miniature drain covers available on the market. Read more about Baby Palmetto Bugs here.

Do palmetto bugs come up through drains?

Palmetto bugs usually enter bathrooms through wastewater drains.

Since drains are directly connected to the sewer system, American Cockroaches, a.k.a palmetto bugs, are extensively found there.

So they find a way to pop up through the drain holes, even if they have to swim through the commode S trap.

They can also come through another hole or a gap in walls, doors, windows, etc.

Generally, roaches keep wandering in search of an ideal environment with plenty of food, humidity, and warmth.

Bathrooms are humid and warm but a little scarce of food, although the tissue paper lying around is no less than a healthy meal they are looking for.

A palmetto bug can also land in your bathroom from somewhere else, like your kitchen or your room, but the drain theory is most of the time why you have it.

Additional Read: There is a palmetto bug in my bathroom!

What liquid can kill cockroaches?

If you are looking for cockroach-killing products, these are the best ones money can buy. Don’t waste your time and get one of these to eliminate all your roach problems.

– Bengal Roach Killer is the best spray to kill a cockroach
– Advion Cockroach Gel Bait is the most effective gel you can buy
– Hot Shot Liquid Cockroach Trapper and Killer is the best trap you can get for cockroaches
– Combat Max 12 Month Roach Killing Bait is the best bait out on the market
– Ortho Home Defence Max Killer is the ultimate choice to get rid of all types of cockroaches

How do you keep roaches from coming up drains?

The drains can be a source of roach infestation in the majority of cases. For the extermination to be successful, we must keep an eye on our drains. There are a

few steps that, if carefully taken, prevent a roach infestation from occurring through drains.

  1. Use bathroom drain covers with smaller holes. This will prevent roaches from coming out of holes. 5 Best Anti Cockroach Drain Covers (Hole SIZES Matter)
  2. I prefer using anti-odor drain covers. They can be closed once the bathroom sink or basin is not used.
  3. Roaches are attracted to filth, so it’s better to keep your bathrooms clean and cabinets closed.
  4. Use boiling water or bleach solution regularly to kill roaches down the drain.
  5. Observe for cracks and crevices inside the bathroom.

You can also use natural palmetto bug repellents for kitchen infestation.

Can you Pour Borax Down Drain for Roaches?

Boric acid and borax are water-soluble. So pouring them into the drain will yield no results, and it must be consumed for boric acid or borax to kill roaches.

Other methods like disinfecting drains with Ammonia, Bleach, or drain cleaning acids are better to get rid of cockroaches in drains.

Additional Read: