Adult Giant Water Bug of the Genus Belostoma

If you have cockroaches in the home, you need to know if it’s a water bug or a roach since they look similar. If you know the difference between a cockroach and a water bug you can put together a better plan to get rid of them.

In this post, we are looking at the water bug vs cockroach to show you the key differences between these two bugs, helping you understand the best way to get rid of them.

Physical Differences: Cockroach vs Water Bug

I. Size and Shape

When it comes to size and shape, there are several differences between water bugs and cockroaches. Water bugs are usually larger, ranging from 2 to 4 inches in length, with wider bodies compared to cockroaches.

A cockroach adult is usually between 1 inch and 2 inches. The cockroach will have oval bodies, 6 legs, and two antennae.

II. Color and Markings

As for the color and markings, water bugs are usually flat and present a tan or brown color.

Cockroaches, on the other hand, come in many different colors, such as light or dark tan, reddish-brown, and black. They might even have a reddish or tan tinge on their bodies.

One key feature that sets them apart is their antennae: cockroaches display long antennae, whereas water bugs have short ones.

III. Wings and Flight

Most roaches have wings but only a few, like the American cockroach, use the wings to fly. Some can fly for short distances, while others merely glide.

Water bugs also have wings, but they can use them to fly longer distances than the average cockroach.

Habitat and Behavior: Water Bug vs Cockroach

1. Living Environments

Water bugs primarily spend their lives in and around bodies of water, inhabiting ponds, streams, and lakes. Water bugs like to be alone whereas cockroaches like to gather in large colonies.

Cockroaches prefer damp areas like damp basements but don’t actually live by bodies of water like water bugs do. Water bugs are not likely to invade your home, this is not a place that giant water bugs will want to live since they love large bodies of water.

Cockroaches will come into your house if you have food and water.

2. Diet and Feeding Habits

Water bugs have a much different diet than cockroaches. Water bugs feed on fish, small or large insects, tadpoles, and small spiders. Cockroaches can eat about anything out there and have more things they can eat depending on how bad the infestation is. They will eat just about anything, including garbage, plants, meats, starches, and sweets.

This is why if you see a roach-like bug in your home it will not be a water bug.

3. Activity and Nocturnal Patterns

The behavior and activity of each are very different, cockroaches are usually more nocturnal and agile. Roaches can run quickly and climb smooth surfaces.

Water bugs move slowly and tend to crawl rather than run. This difference in their speed and looks can help you identify which one might be in your home. Do water bugs bite humans? The answer is yes if you are walking barefoot in water areas and step on one they can bite you.

Can cockroaches bite a person? Usually, they do not bite people unless there is a large infestation.

The cockroach would be much more likely to be in your home than a water bug.

Health Risks and Allergies: Water Bug vs Cockroach

When it comes to water bugs and cockroaches, both can pose various health risks and trigger allergies for some people. In this section, you’ll learn about the potential dangers associated with these insects, specifically pathogens and bacteria, as well as asthma and allergy triggers.

I. Pathogens and Bacteria

Water bug vs cockroach who spreads more illnesses? Both can carry bacteria and pathogens on their bodies, transferring them to surfaces in your home. The bug that will most likely make humans sick the most is the cockroach, this is because they are more likely to invade a home than a water bug.

Cockroaches, being scavengers, are known to feed on almost anything, including garbage and pet food. This means they come into contact with various microorganisms that can cause you and your family to get ill.

Water bugs, on the other hand, are predators that primarily feed on insects, fish, and tadpoles. Although their diets might seem cleaner than cockroaches, they can still carry bacteria and other pathogens that can pose a risk to your health.

II. Asthma and Allergy Triggers

Cockroaches can definitely trigger allergies and even asthma symptoms in some people. Roaches in the home can lead to cockroach allergens, which can cause chronic symptoms that last longer than other seasonal allergies (WebMD).

If you know you have roaches in the home you may have a cockroach allergy if you experience some of the following symptoms:

  • Skin rashes
  • Nasal congestion
  • Sneezing, or itching around the eyes, nose, and mouth

These allergens are commonly found in their droppings, saliva, and body parts.

In comparison, there is less evidence of water bugs causing allergies or asthma, as they are typically not as common in domestic environments.

However, it’s still important to keep your living area clean and free from both water bugs and cockroaches to minimize potential exposure to allergens.

Prevention and Control Measures: Water Bug vs Cockroach

I. Sanitation and Maintenance

You need to keep your home clean, plain, and simple. It is crucial in preventing water bug and cockroach infestations. To keep your home clean, follow these tips:

  • Keep your living spaces clean and clutter-free, as this reduces hiding spots.
  • Regularly dispose of garbage and keep trash cans tightly sealed.
  • Fix any leaks in your plumbing, as these insects are attracted to moisture.
  • Store food in airtight containers and avoid leaving food out overnight.
  • Put the dog and cat food dishes away at night so as to not attract cockroaches.

II. Exclusion Methods

Preventing these insects from entering your home is another important step. You need to do this:

  • Seal any cracks or openings around doors, windows, and walls with caulk or weather-stripping.
  • Install screens on windows and doors to prevent entry.
  • If you live in a brick home, use steel wool to plug weep holes and prevent entry.

III. Chemical and Non-Chemical Solutions That Work

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If you know you have cockroaches or water bugs in the home, how do you get rid of them? Here are some chemical and non-chemical solutions to consider:

  • Place sticky traps in areas where insects are frequently seen to catch and monitor them.
  • Use chemical insecticides or natural remedies such as boric acid or diatomaceous earth to target areas where these insects are likely to be found.
  • Consider hiring a pest professional for serious infestations, as they have access to more powerful solutions and can help identify the root causes.


In summary, it’s essential to understand the key differences between water bugs and cockroaches to accurately identify and address any infestations you may encounter in your home or surroundings.

As we’ve seen, water bugs are larger, typically grayish or brown in color, and primarily live in water, like ponds, streams, creeks, and lakes.

On the other hand, cockroaches are smaller and redder in color. Cockroaches like damp areas but do not usually live by lakes or streams like the water bug. If you find a roach in the home you have to deal with them quickly before they reproduce to a large infestation level.

You now know the difference and can make a plan to get rid of roaches or water bugs if they enter your home. Don’t hesitate to consult with an exterminator if you’re unsure or need assistance in managing these bugs.


Is the oriental cockroach the same as a water bug?

The oriental cockroach is commonly called a water bug but the water bug we discuss in this article is not the same. They call the oriental cockroach a water bug because it loves damp and moist areas so much. You can check out this post if you think you have oriental cockroaches. If you do have oriental cockroaches in your home you need to get rid of them quickly.

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