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Water Bugs: What Are They Exactly and How to Get Rid of Them

Giant Water Bug Lethocerus Americanus

Are water bugs infesting your home? Did you just spot a big, brown bug underneath your sink? Most of us use the term ‘water bug’ to refer to many different pests, including cockroaches. But true water bugs are entirely different insects.

True water bugs (Lethocerus americanus) belong to the order Hemiptera, while cockroaches are part of Blattodea. But despite this difference, it’s easy to understand why we use this term interchangeably.

But if you’re spotting some ‘water bugs’ inside your home, then they’re most like cockroaches (and Oriental cockroaches in particular) that require cockroach control tactics.

This article discusses not only what water bugs are, but how to differentiate them from cockroaches, how to prevent everything we refer to as ‘water bugs’ inside our homes, and how to also control them effectively.

What is a Water Bug?

The term “water bug” is a common nickname for many pests, particularly cockroaches.

However, true water bugs (Lethocerus americanus) are aquatic insects that are native to the United States and Canada and belong to the family Belostomatidae. They are also called giant water bugs, toe-biters, and electric light bugs.

Water bugs, as the name implies, are large insects that live in freshwater ponds and streams. They use their flattened hind legs, which resemble oars, to swim and grab plants near the water’s surface. They also have long antennae and a pair of large eyes.

Water bugs prey on other aquatic insects, crustaceans, tadpoles, salamanders, fish, and amphibians. They can even catch and eat animals that are 50 times their size!

If you’re finding these inside your home though, you’re most likely referring to the Oriental cockroach or Blatta orientalis.

These are cockroaches, not ‘true water bugs,’ but they’ve earned this nickname because they like to hang out in wet places. They have been known to use water pipes to get to higher floors in apartment buildings. And they like to hide in damp, dirty places like garbage chutes and sewage pipes.

Although Oriental cockroaches do not cause structural damage, they can leave behind a distinct musky ‘roachy’ odor in extreme cases when there are infestations.

What Does a Water Bug Look Like?

Again, the answer depends on whether we are talking about the true water bug or the Oriental cockroach. Any pest referred to as a water bug typically has a hardback, is tan to dark brown in color, has antennae, and is rounded or beetle-like in shape.

When it comes to true water bugs, their appearance differs from that of the oriental cockroach.

Water bugs can be recognized by their large size and flattened hind legs. They can be any shade of brown and can be up to 2 inches in length. They have long antennae and large eyes.

As an added bonus, water bugs are able to breathe underwater thanks to two tubes at the very end of their abdomen. When the bug is completely submerged, these tubes extend all the way to the water’s surface.

They prefer to make their homes in ponds, lakes, and creeks with a lot of vegetation near the water’s surface. They can grow to be over four inches in length, and they rely on this vegetation for shelter and food.

These bugs, which are also called “Electric light bugs,” are attracted to lights that are left on at night. Sometimes, as they fly at night toward a porch light far away, they land in a swimming pool or backyard pond.

If you have a true water bug in your pool, which is unlikely, be careful. In addition to its common name, the Giant water bug is often referred to by the nickname ‘toe biter’ because of its tendency to bite between the toes if it is stepped on.

As a result of the paralyzing venom they use for hunting, their bites can be excruciatingly painful and cause lasting harm to certain individuals.

Giant Water Bugs (Lethocerus Americanus)

Giant Water Bugs (Lethocerus Americanus). – Photo Credit: Dreamstime.

Oriental Cockroach (Blatta Orientalis)

Oriental Cockroach (Blatta Orientalis) – Photo Credit: Dreamstime.

Water Bug vs Cockroaches

Water bugs and cockroaches are different kinds of insects. The giant water bug (or ‘true’ water bug) is the largest ‘true bug’ and a member of the order Hemiptera.

Although it is an aggressive aquatic predator, it’s not a household pest. However, avoid handling one if you don’t want to receive an uncomfortable water bug bite.

A roach, on the other hand, can thrive in your home since it has all the food, shelter, and water they need to survive. Cockroaches belong to the Blattodea order of insects. They prefer living in places that are damp and humid, but not in water.

In terms of appearance, cockroaches are typically reddish or brownish in color, with the exception of oriental cockroaches (Blatta orientalis), which are much darker.

The antenna is the primary difference between cockroaches and water bugs.

Cockroaches typically have very long antennas, and their heads are usually hidden beneath the thorax, which is where the cockroach’s legs and wings are attached.

Also, remember that most cockroaches and water bugs can fly. However, the oriental cockroach, which is frequently misidentified as a water bug, cannot.

Female oriental cockroaches lack wings entirely, whereas males’ wings are so small that they are virtually undetectable by most people. They only cover a portion of the abdomen.

Therefore, an oriental cockroach is probably what you’re dealing with if the intruder doesn’t have wings that can be seen. On the other hand, it’s most likely a water bug if it flies.

Comparison between Giant Water Bug (Lethocerus Americanus) and Oriental Cockroach (Blatta Orientalis)

Photo Credit: Dreamstime.

Where Do Water Bugs Come From?

If you’re seeing water bugs inside your home, then they’re most likely not true water bugs (or giant water bugs) but rather cockroaches. As we mentioned earlier, Oriental cockroaches are the type of roach commonly mistaken for water bugs inside so those are most likely what you’re encountering.

Apart from indoors, they also happily live outdoors in dirty and damp environments such as garbage receptacles, sewage pipes, and rotting leaf piles. Indoors you’ll find them in places like under your sink in the bathroom or kitchen, behind your refrigerator, or hidden in crevices.

If these pests are finding their way inside, it is highly likely that there is a source of water or food attracting them.

Do Water Bugs Bite?

True water bugs do in fact bite and their bites can cause damage, and even lead to allergic reactions. But the ones found indoors, such as Oriental cockroaches, don’t bite but they can still be quite harmful.

Cockroaches in general can spread human disease and trigger allergies and asthma. Oriental cockroaches, in particular, can also spread contaminants that can lead to diarrhea or food poisoning.

How to Prevent Water Bugs

Water bugs can definitely be a nuisance, but there are several steps you can take to prevent them from entering your home or garden.

Remove any standing water near your home, such as puddles or birdbaths.

Seal any cracks or crevices around windows and doors.

Install screens on windows and doors to keep water bugs out.

Use insecticides to kill any water bugs that have already entered your home.

Keep your home clean and free of food debris, which can attract water bugs.

How to Get Rid of Water Bugs

If you’re spotting water bugs inside your home, then you need to take measures to control cockroaches straight away.

The first step is to identify the source of the water bugs. This can be done by looking for signs of them such as droppings, egg cases, and shed skins. Once you’ve identified where they’re coming from, you can take steps to eliminate their access to food and water sources.

The next step is to reduce clutter in your home, as this will make it harder for the pests to hide. You should also seal any cracks or crevices in your walls and floors, as this will prevent them from entering your home.

Finally, you can use a combination of chemical and non-chemical methods to control the water bugs. Chemical methods include using insecticides that are specifically designed for cockroaches, while non-chemical methods include using traps and baits.

We have also written and shared a detailed guide to help get rid of water bugs and cockroaches entirely, and we recommend you check it out. It includes the 6 steps you can take to get rid of them effectively.

Other Pest Control Articles from Planet Natural:

Palmetto Bug Or Cockroach: Differences & How to Kill Them

Cockroach Control: Get Rid of Cockroaches Step-by-Step

Baby Cockroach: What They Look Like + How to Get Rid of Them

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Melissa Pino is a biologist, master gardener, and regular contributor for Planet Natural. Melissa's work focuses on promoting environmentally-friendly practices, helping people create healthy gardens and finding ways to achieve overall health and wellness.