Does Soap Kill Roaches?

Cockroach extermination methods and their effectiveness can vary, whether you use some commercial baits, hire an exterminator, or even try some home methods using substances you can find around the home such as bleach or Listerine.

The latter options are usually a homeowner’s first course of action before purchasing products or hiring a professional. Another home solution for killing roaches is known to be soap. But can this everyday household item really kill roaches?

Soap can be used to get rid of cockroaches. Soapy water is effective in killing cockroaches if you drown them in it because it affects their outer coating and blocks the breathing holes in their lower abdomen (spiracles). The roach will suffocate to death if its protective coating is removed.

However, like the other well-used household solution, bleach, soapy water is not the most efficient solution in repelling roaches because it lacks a repelling odor with the ability to irritate them.

Does Soap and Water Kill Cockroaches?

The mixture of soap and water can be an ideal method to kill roaches if used in the right way.

Mixing soap and water allows you to spray larger amounts of soap on cockroaches. The water will spread the soap to a larger area and if submerged in the water, the cockroach will die quicker due to drowning.

High-concentrated soaps will work faster, and roaches can be dead within 12 hours if they receive a large quantity all offer their bodies.

Dishwashing liquid is the most used and effective type of soap solution you can use against roaches, but they need to be completely covered or submerged in the solution to have the greatest effect.

a cockroach next to bar of soap

How Does Soap and Water Kill Cockroaches?

The exoskeletons of many insects are covered in a waxy substance that serves as a defensive barrier against injury. It also aids the cockroach in staying hydrated and repelling water off its body.

High concentrations of soap have a toxic effect on the protective coating of the insect’s body, which in turn makes it impossible for them to breathe.

When you wet a cockroach with soapy water, the soap removes this protective, waxy coating. This leaves them more susceptible to significant water loss and water damage.

Roaches have a different respiratory system than humans. Instead of lungs, they contain spiracles. These breathing tubes allow them to intake air and eliminate carbon dioxide. They can keep these pores closed in order to avoid drowning.

Soapy water disrupts this process – the chemical reaction between high concentrations of soap and water results in blocking the breathing holes in the cockroach’s abdomen, which leads to suffocation.

Types of Soap That Kill Roaches

Any type of soap should be effective in getting rid of roaches. The main aspect is to focus on finding high concentrated soaps that are powerful enough to remove the protective coating from the cockroach’s body.

Dishwashing liquid, for example, contains substances that can be very active against other types of insects but are less effective when used against other species.

You can mix dishwashing liquid with water and use it as you would regular soap, but plain soapy water is also effective when used in large amounts.  

Soap products that are not meant to be mixed with water, like laundry detergent or general-purpose cleaners should also work. Just make sure the soap you use is highly concentrated.

If you are not sure about the soap’s concentration, you can test it on a water-resistant surface (like tile) to prove its effectiveness before using it on roaches.

Does soap kill roaches?

Is Soap Good for Getting Rid Of Cockroaches?

Soap and water will kill cockroaches if they are completely submerged in it.

It is not the most efficient method because it does not come with a repelling odor that can irritate roaches and make them avoid areas where the soap solution is sprayed.

Cockroaches have developed a natural immunity to water, so spraying water alone will not be effective enough against cockroaches.

Soapy water is still the best solution to get rid of roaches and it can be used in conjunction with other methods that will irritate them.

Make sure you use high-concentrated soaps because they work faster and more effectively than regular soapy water.

Cockroaches submerged in soap solution for at least 30 minutes will drown and die.

The time it takes to fully eliminate the cockroaches depends on several factors, including how many are there, what type of soap you are using, how concentrated it is, etc.

How to Kill Cockroaches With Soapy Water

The best way to kill roaches using soap is to make a spray solution.

When combining dishwashing liquid (Dawn) or laundry detergent with water to kill roaches, the basic guideline is to put in enough so that the surface tension of the mixture is broken.

  1. Grab a clean spray bottle and fill it about 3/4 full with water
  2. Add 6 teaspoons of liquid or powdered soap
  3. Give your bottle a good shake
  4. Spraying directly on roaches to give them a thorough coating
  5. Spray their hiding places and entry points with a generous layer of the solution, which can be easily washed away later

Cockroaches are tenacious pests that need to be sprayed on a regular basis. It may take several rounds of spraying for the soapy formula to have the desired effect.

Dawn soap is the most effective roach killer since it also contains sodium chloride, which when combined with other soap qualities, suffocates roaches. This will swiftly and effectively eliminate the cockroach.

If you have the ability to flood the cockroach nest or hiding place with water, then adding Dawn dish soap or another detergent will be an effective and clean way to exterminate the colony.

Even better, if you have trapped the cockroaches and want to find a way to quickly kill them, find a large bucket and fill it with soapy water. Then simply dump it on the roach colony and they will immediately begin to drown with no escape from the slippery sides of the bucket.

Can You Use Soap To Kill Roaches in a Toilet?

If you have cockroaches in your toilet bowl, by either accessing your plumbing or you have put them in there after catching them, soapy water may be the best method to ensure they are dead.

Cockroaches will usually survive in water for enough time to find an escape route, but if you add soap to the equation then this makes their life much harder. As explained above, the soap will damage their exterior protection and in turn, block their method of breathing. This will drown the roaches in your toilet not give them time to escape back through your plumbing.

cockroach in a toilet about to be flushed

Can Soapy Water Kill Cockroach Eggs?

Soapy water will not be effective in killing cockroach eggs. They have a protective shell that is not the same as the adult cockroach shell. This eggshell case will protect it from water and other substances such as soap.

You would have to smash open the outer protective cover that contains the eggs, which would effectively kill the eggs anyway so soap would not be needed.

However, if you are attacking a nest it’s always a good method to use soap on the eggs to clean them away and the residues that they leave behind.

Once you find where the eggs are hidden, you can dispose of them appropriately, which usually involves crushing them and putting them in a sealed trash bag.

Can Roaches Eat Soap?

The amusing aspect of all this is that cockroaches consume everything, even bar soaps. When they consume bar soaps, they do not die.

Cockroaches will consume soap if no other food is available in your bathroom or kitchen. A bar soap, in particular, is composed of oils and fats. The carbohydrates and protein contained in certain soaps are an ideal feast for a roach.

When using the above soap and water solution, it’s not the soap being ingested that kills the roach. It’s when the water is combined with soap, because soap aids in the breaking of surface tension on the water, it is quickly absorbed into their breathing pores.

dead cockroach

So Is Soap A Good Way to Kill Roaches?

It may seem like soap and water are low-tech pesticides, but they can be helpful in certain circumstances. The cheapness of this method means it is always worth a try before you implement other solutions which may be harmful or dangerous to children or pets. It can also be highly effective in eliminating the musty smell that cockroach nests leave behind.

Non-toxic home remedies for roach elimination should always be your first line of defense and can sometimes be just as effective if the conditions are right.

While a soap solution may effectively reduce the number of cockroaches in your home or apartment, it will not cure your property of an infestation. It will just exterminate roaches that you directly target with the solution. Cockroaches will continue to lurk in their usual spots.

Some soaps may also have zero effect on cockroaches, so beware this route may be completely ineffective.

Commercial pesticides and bait traps will deliver a higher kill rate and are probably your next best solution if the soap solution is not working as you wish.

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