Does Soap water kill Cockroaches? Instantly or Later?

If you are distressed by roach infestation and looking for a method to kill them, you will want to know: Does soapy water kill roaches?

Roaches are exceptionally irritating creatures, and everyone wants to eliminate them. The reason for this varies from person to person, and some are allergic to roaches, while some are afraid of them.

But the main reason is their disease-causing nature, so In this blog, I will tell you if you use soapy water to kill roaches or what its usage method is. 

I have been researching pest control and would love to share some tips and tricks with you, so what are you waiting for? Let’s get started.

Does Soapy Water Kill Roaches?

Yes, soapy water can quickly kill roaches. For this, you have to first make a solution with water. Mix some soap with water, put it in a spray bottle, and then spray it on the roach you want to kill. Soapy water kills roaches by blocking the oxygen supply to their cells. As a result, cells of different organs start dying.

Oxygen is essential for cells to live, and cells, in turn, are important sites for carrying out various life-dependent reactions; therefore, a shortage of oxygen results in roach death.

Spraying soapy water 2 to 3 times is enough to cut out the roach’s oxygen supply.

Does Soap Kill Roaches?

Soap can kill roaches by causing interference in the breathing mechanism of cockroaches, but for better results, it is mixed with water so that it can be applied to the whole body of the roach.

Because enough soapy mixture is required to cause hindrance in the entrance of air through spiracles, therefore it must be poured into a spray bottle that results in maximum exposure.

Moreover, the death of roaches due to a soapy mixture also depends on the gender of a roach and the species of that particular roach.

According to the research that I have conducted, a soapy mixture is more effective in killing a male roach as compared to a female. 

The reason is that the structures of female roaches have developed resistance against the harmful impact of soapy water.

Can Soapy Water Kill Roach Eggs?

Roach eggs are the primary source of roach infestation in the house because roaches have a high production rate and produce several baby roaches in just a few days.

Female roaches produce an egg pouch containing eggs in it, and a single egg pouch contains more than 10 eggs in it, so you can predict the reproduction rate of these species.

So, it is imperative to remove roach eggs if you don’t want to develop roach infestation. The urge to get rid of roach eggs often raises a question: can soapy water kill roach eggs?

So, the simple answer is yes, but you have to first take out the roach eggs from an egg pouch called oothecae. 

Because oothecae provide the egg protection against any harmful chemicals or pathogens so therefore first burst the ootheca and then apply soap water spray on the eggs.

In addition, if you want to increase the reactiveness of soapy water, don’t use normal water to make a solution; instead, use boiling water. 

Does Dish Soap Kill Cockroaches?

As I have mentioned above, soapy liquid can kill roaches which means that it is a soap that has the tendency to kill them. 

Now you must have a question in mind: which type of soap? A dishwashing soap can act effectively because it contains more chemicals to kill pathogens present in dishes.

Now there are two types of soaps available for dishwashing. One is in the form of a bar, and the other is a liquid solution so let’s see which works more effectively in killing roaches.

1. Bar Dish Soap

You can use bar soap for dishwashing. It also includes chemicals, but these are primarily associated with the skin. 

For Example, these soaps also have some chemicals that can kill skin bacteria.

They contain chemicals or substances that can deal with dead skin cells that block our skin pores and also allow the growth of certain bacteria that cause skin infections.

This makes our skin smooth and flawless and also works effectively to kill roaches. These also contain some laboratory-made chemicals that produce fragrances.

  • To use these chemicals for killing roaches, you have to convert the soap from solid to liquid form. 
  • Take 16 tbsp of water. 
  • Then add 6.4 tbsp of bar soap in liquid form.
  • Now mix it until a foam appears. 
  • Then add the solution to a spray bottle and shake it again before use.

2. Liquid Dish Soap

If you don’t want to carry out a process of converting solid soap into liquid, then I suggest you use liquid dish soap to kill a roach.

Liquid dish soap contains chemicals that are used to kill bacteria present in dishes. These chemicals act as poison for cockroaches. 

Moreover, such soaps also include chemicals that are able to remove oil from dishes. Such chemicals can attack the central nervous system of roaches’ brains.

So, the chemicals in liquid dish soaps are more dangerous for roaches. Moreover, such soaps have nothing to attract roaches as some soaps contain fats and starches that roaches use as food.

  • To use liquid dish soap, you don’t need to carry out a conversion mechanism.
  • Take 2 teaspoons of liquid dish soap.
  • Add 16 tbsp of water in it to dilute the solution.
  • Now mix it until a foam appears. 
  • Then add the solution to a spray bottle and shake it again before use.

Does Dawn Dish Soap Kill Roaches?

Dawn dish soap is the same as any other dish soap. It can also kill roaches by attacking its protective shell and spiracles. It contains some harmful chemicals that also act as a poison.

The composition of dawn soap includes poisonous chemicals like triclosan that can play a pivotal role in killing a roach. For this, you have to create a solution of dawn soap with water.

Dawn dish soap is already present in liquid form, so it does not require the melting process. Besides, it is required in a minute amount. 

2 to 3 sprays of dawn dish soapy liquid can fully cover the openings of roaches through which air enters, and the exchange of gasses occurs. This will cause the death of the roach in one hour.

Does Vinegar and Dish Soap Kill Roaches?

Vinegar is not used to kill a cockroach; instead, it produces a smell that roaches hate, so they avoid coming near it. So if you want to make use of dish soap, mix it with borax.

This will affect the central nervous system, outer shell, and breathing mechanism of roaches, but vinegar will help you to keep roaches away. 

If you have a severe roach infestation and want to protect your things like books and electronics from roaches, then it will help you out.

Mix vinegar with dish soap or water; you can also use it with lemon juice. Fill it in a spray bottle and spray it on the things you need to protect.

Why Does Soap Kill Cockroaches?

You will be eager to know its answer. You may have heard many things about the answer to this question. People are often confused and don’t know the exact answer.

As I have mentioned above, these soaps include some chemicals that are able to kill bacteria which acts as a poison for such insects, so let’s see how this poison acts on cockroaches.

1. Attacks On the Outer Shell of Cockroach

All insects, including cockroaches, possess a hard and rigid outer shell. Have you ever wondered what this shell is for? Actually, this shell provides protection for cockroaches.

It is hard and has the ability to bear pressure and stress. Moreover, it covers the critical organs of cockroaches and blocks the entrance of pathogens and chemicals inside the organs.

It also holds the amount of water in the body and prevents dehydration. So, when soapy water is sprayed on a roach, It attacks this protective covering and detaches it from the body.

This causes the entrance of harmful chemicals inside the roach organs, and also water moves out of the body, which causes severe dehydration and results in roach death.

2. Blocks the Air Holes

As I have discussed above, cockroaches need oxygen for the life of their cells, just like humans. For this purpose, a roach undergoes the exact mechanism of breathing, just like humans.

But the difference is that humans breathe by using their lungs, while cockroaches breathe by using small holes called spiracles. The air enters through spiracles, and carbon dioxide is exhaled.

So, when you spray a soapy liquid, it blocks these openings and doesn’t allow air to pass through them. This results in a lack of oxygen and results in cell death.

Here the notable point is that roaches have the tendency to open their spiracles by contracting the muscles, so I suggest you spray enough layers of soapy liquid to cover the openings.

The density of soap also matters to cut out their oxygen supply. If you use enough spray, the roach will die less than 24 hours after exposure to liquid.

Moreover, the concentration also plays a vital role; a soapy liquid with up to 32% concentration is proven to be effective.

Do Roaches Eat Soap?

As you all know that roaches are known as flexible insects, and the reason is their ability to eat everything. They can also feed on objects and things other than food, spending upon conditions.

This idea often raises a questioning mind: do roaches eat soap?

So the short answer to this question is yes, they do; therefore, to kill a roach, it is essential to make a poisonous spray by adding water to it.

Cockroaches can be attracted to bar soap when there is a food shortage or more competition for survival. The reason for their attraction is the presence of fats and oil.

Besides, such soaps also have a tempting smell, so they may be attracted to them. Moreover, as I have discussed above, roaches eat foods that have natural substances.

This also proves their attraction to bar soaps because they contain carbohydrates, fats, and proteins and mostly contain natural ingredients as compared to chemicals.

However, the chemicals also have some sound effects on roaches. They can carry out a repair process for roaches. 

So to get nutrients for energy and growth, roaches can eat soaps that have natural substances in them, but they don’t prefer these to eat.

Method to Use Soapy Water to Kill a Roach?

The effectiveness of soapy water also depends on the method you use to make the solution.

  • Don’t use soap alone. Always add water to make the soapy water solution.
  • Use a spray bottle to apply the solution.
  • Use warm water to make a solution if possible.
  • Spray continuously for better results.
  • Mix the solution properly for this. Shake the spray bottle several times.
  • The concentration of soap must be above 32%. It is essential to affect a roach.
  • Add borax to have more effective results.

Is Soapy Liquid an Effective Poison?

Soap and water are an excellent killing mixture for roaches. However, it has some drawbacks as well. But if you only ask about its poisoning effect, I will answer you yes.

I have personally used the soap and water mixture to kill roaches, but it does need some considerations. So let’s discuss the properties which make it a suitable poison.

I will also tell you about some drawbacks of it as everything that has advantages also has some limitations as well.

Pros of Using Soapy Water

I have mentioned some advantages of soapy water, which justify its use to kill cockroaches.

1. Safe to Use

As you know, other insecticides and pesticides contain some harmful chemicals that can be poisonous to humans. For such chemicals, you have to follow some precautionary measures.

So it is hard to use these insecticides. Besides, those sprays can also cause damage to our clothes and accessories; therefore, we must have to think before using such sprays.

But, this is not true for soapy liquids. This is not because they don’t contain chemicals; instead, the reason is that these chemicals do not produce any toxicity in humans.

So you can use this mixture in place of an insecticide.

2. Affordable

Controlling roach infestation is a costly process as you have to buy some products like roach baits, insecticide sprays, specks of dust, insect growth inhibitors, and much more.

All the above-mentioned products are costly. Besides, if you still don’t get rid of the roach infestation, you have to call professionals, which is the most costly process.

Making a soapy liquid is an affordable process as it only requires an ordinary dishwashing soap which is almost available in every house.

But if you don’t have one and need to buy it, then you don’t need to worry as it is less than $1 and can give you better results than expensive products. 

Cons of Using Soapy Water

As I have already discussed, this method has some drawbacks which are essential to discuss before carrying out the process, so let’s discuss them in detail.

1. Have to Compromise On Effectiveness

If you want to use soapy water to kill a roach, you must have to consider a roach type first. Just like other insecticides, it does not prove to be 100 % effective.

Some species of cockroaches can survive the attack of soapy water by carrying out various survival mechanisms, so it is essential to study the effect of soapy spray on roach species.

You don’t need to, as I am here to tell you about this matter. Actually, if you spray a soapy liquid mixture on an American cockroach, it will show some responses showing that it is dying.

But unfortunately, there is a 50 % chance of its survival. So if you have an infestation of American cockroaches, use some other method for them.

On the other hand, the most common species of cockroach, which is German, is more sensitive to soapy spray, so you can apply this method to it.

The table below shows the effect of soapy liquid on American cockroaches.

No of sprays5
Concentration32 %
No of cockroaches deadMore than 50 %
Time taken24 hours

2. It Can Deal with a Small Number of Roaches.

Spraying a soapy liquid on a roach looks more accessible, but it is not as effortless as it seems. You can spray on a single cockroach that you find wandering around your kitchen.

But it is difficult to find all the roaches and to expose them to spray individually. So if you have a roach infestation in your house, follow other methods to deal with it.

Final Words:

There are several insecticides in the market but people who want to avoid spending money often ask, does soapy water kill roaches?

I have tried my best to provide a genuine answer. Soapy water kills roaches, but females and American roaches show some resistance. It has some advantages as well as disadvantages.

I have discussed all the pros and cons of this process and its methods. So, read the entire essay to learn something interesting. 


Does Laundry Detergent Kill Roaches?

Yes, laundry detergent mixed with water can kill roaches in 24 hours by inhibiting the supply of oxygen to specific tissues and organs, resulting in loss of function and, eventually, death.

Does Pine Sol Kill Roaches?

If you expose a cockroach to pine sol, it will run away, so trap a roach and then expose it to the harsh chemicals present in pine sol; this will result in death.

How Fast Does Soapy Water Kill Roaches?

Soapy water can kill roaches in two ways, by removing the exoskeleton and by blocking the oxygen supply; the former method takes a few seconds, while the latter can take 24 hours.

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