Waterbugs vs Roaches | How To Tell The Difference

An insect infestation in your home is one of the most frustrating problems. The first step in stamping out troublesome bugs is identifying what they are. Here, you will learn to tell the difference between two pests, waterbugs and cockroaches, and how to deal with them.

Water Bugs Vs Cockroaches

Now that you know that water bugs and roaches are separate insects, here is how to tell them apart reliably.

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These are the qualities of the average cockroach.


Cockroaches are typically 1.4 to 1.6 inches (or 35 to 41 millimeters) long. The largest roach can grow past 2 inches (or 50.8 millimeters) long; however, the most commonly encountered species are smaller.


Cockroaches are notoriously adaptable and live in many different habitats around the world. They typically prefer a warm environment that is dark and wet. In addition, they are drawn to dirty, overly damp areas, particularly ones with excessive amounts of food. The latter attracts them to highly populated places such as apartment buildings or grocery stores.

Not many cockroach species enter human habitats, but the ones that do will seek similar conditions. For example, they usually enter a building through its pipes, drains, or sewer systems. However, you can expect to find them in basements or kitchens more often.

Eating Habits

Cockroaches are voracious eaters and will eat anything from a plant or animal. They are particularly attracted to sugary, greasy, starchy, or rotten food. If no actual food is around, they will resort to eating wood, cardboard, dead insects, paper and glue, leather, and more organic material.


Roaches are quick and devoted to self-preservation. They are hard to catch and prone to hiding in the dark. Despite being simple creatures, they have a strong group mentality: they are adept at making quick decisions together and perform efficient evaluations of a new area’s fruitfulness and safety.

Pest Determination

Roaches are both extremely hard to get rid of and annoying. Where there’s one roach, there are a hundred: they often swarm in large groups for protection, reproduction, and in a pinch, emergency food. They are highly adaptable to new environments. Their speed, quick reflexes, and tendency to hide in inaccessible places make them hard to kill.

Roaches also breed extremely fast. If left unchecked, a roach infestation can quickly grow unmanageable. Exterminators often recommend recurring treatments for your home to ensure they all stay gone.

Bite Risk

Though cockroaches will bite both living and dead humans, biting is not typical roach behavior. They do not feed on humans or pets and will only bite if they feel threatened or have no other food available.

Even then, they may not be trying to bite you, but dead skin or food remains stuck to you. The most common places to find roach bites are the mouth, hands, and fingertips. Since cockroach mouthpieces are not strong or sharp, their bites have mild side effects. These include minor irritation, skin lesions, or swelling.

Water Bug

These are the qualities of the average giant water bug.


Giant water bugs are typically 2 inches (50.8 millimeters) long. The largest variety of water bugs can grow up to 4 inches (101.6 millimeters) long. 


As their name suggests, water bugs are found in watery environments such as ponds, lakes, and even pools. While they mostly stay in bodies of water, they can also be found in overly moist areas such as sewers, flooded trash cans, and damp places underground such as basements. 

Eating Habits

Unlike the scavenging roach, water bugs actively hunt for food and have a specific diet. They eat insects, small fish, and even small animals if they can catch them. When they bite, their mouthpieces inject a toxic enzyme that liquefies their prey’s insides, similar to how a spider feeds.


Water bugs are much less timid than roaches. Not only will they bite if threatened, but they also hunt animals over ten times their size without fear or restraint and hold them immobilized to feed for hours. They are not often found in groups, preferring solitary lives.

Pest Determination

Water bugs typically do not infest homes. If you find one in your house, it likely wandered in by mistake, looking for a wet place. So, unless you see them in your swimming pool, they are not pests.

Bite Risk

Though water bugs do not feed on humans and will only bite you if threatened, their bite is stronger than a roach bite. So be careful where you swim, so you don’t wind up with bitten toes!

The bite and the accompanying venom cause mild pain and itchy red bumps.

Cockroach vs. Water Bug Identification

Referring back to your notes in identifying insects is doable, but to help you out more, here are images of each insect so you will know what you are looking at.

Waterbugs vs Roaches

This is a photo of the average American cockroach. As you can see, it is tan-brown and has a small, weak mouthpiece. It has six unremarkable legs and a smaller body than the water bug.

Water Bug

This is a photo of the average Giant Water Bug. As you can see, it is brownish-red and has large beakish pincers protruding from its head. It is larger and wider than the cockroach, with stronger front legs and oar-like back legs.

Both species possess antennae and weak wings.

Types of Cockroaches

After you’ve identified which insect is infesting your home, the next step is to identify which type of roach or water bug it is. Here are the most common types of cockroaches you might find in your home.

The American Cockroach, also known as the Palmetto Bug or Bombay Canary, easily lives up to its alternate names. Of all the roach varieties that commonly infest houses, this one is by far the largest, reaching up to 2 and one-eighth inches (54 millimeters) long. They are identified by the yellowish band just behind their heads.

The German Cockroach is the most common species of cockroach in the world. It is much smaller than its American counterpart, measuring only one-half inch to two-eighths of an inch long. It is also lighter tan or brown and has parallel dark brown stripes down its back.

Types of Water Bugs

Here are the most common types of water bugs that you might find in your home or any body of water near your home.

Giant Water Bugs are also known as electric light bugs for their attraction to lights and toe-biters for their powerful nibbles on unsuspecting swimmers. They are notably large, growing up to 2 inches (50.8 millimeters) long. It is flat, gray-brown to dark brown, and has a wide oval shape. Their hard back shell makes them resemble large beetles or species of cockroaches.

Backswimmers, often mistaken for the similar variety of water boatmen (which are larger, lack wings, and have long scooping forelegs), are a species of water bug often found in groups. They are light yellowish-brown in color, with their wings being lighter than the rest of their bodies. They have very long back legs that they use to paddle around the water on their backs.

How to Get Rid of Roaches and Water Bugs

Now the step you have been itching for: exterminating the insects from your home. These are the most effective ways to get rid of roaches and water bugs.


Cockroaches are an utter pain to get rid of, and it can take anywhere from one to six months to entirely rid your house of the insects.

The best method of keeping them away is to practice suitable prevention methods: caulk any cracks in your home they could sneak in through from outside, ensure there are no overly moist or damp places in your home, and never leave food lying out in the open or spills uncleared. 

Check every piece of furniture you bring into the house to ensure nothing is hitching a ride!

If you cannot call a professional exterminator, you will still need to use professional-grade pest control products to get rid of roaches. Clean your home thoroughly and seal away any food before you begin.

Next, use insecticides to kill any roaches you can see (don’t bother trying to smash them, they’re too fast and durable anyway). Use roach bait and glue traps to draw any roaches still hiding in your pipes, walls, etc. out into the open. Keep in mind that roaches are most active at night.

A common home insecticide is diatomaceous earth (DE), which dehydrates roaches to death when they come in contact with it. Homemade roach bait can be laced with baking soda, boric acid, and borax, all of which are fatally toxic for roaches to ingest. Be aware of any allergies or sensitivities you may have to a material before using it to kill insects in your home.

Diatomaceous Earth is available on Amazon.com among the most effective remedies for water bugs.

Other remedies include boric acid, water bug trap, and essential oils such as peppermint and lemongrass.

You can also kill water bugs naturally by pouring baking soda, detergents, vinegar, or alcohol into their nests.

Diatomaceous Earth Crawling Insect Killer

Water Bugs

Water bugs are easier to get rid of because they do not swarm like roaches: if you find a water bug in your home, there most likely aren’t any more where that came from. They do not want to make permanent homes in your house anyway.

If you don’t feel like using the old paper towel under a cup method to evict the giant water bugs, a good smash with a flyswatter or other heavy object will do. Otherwise, the same traps, baits, and insecticides that kill cockroaches will work just as well for water bugs.

Verdict: Cockroaches vs. Water Bugs

In summary, cockroaches are smaller and timider than giant water bugs, which are large and aggressive, but they are much faster to breed and infest homes. Water bugs typically find their way into your home or pool by accident, but cockroaches actively seek a permanent nest with food, water, and shelter.

Both bugs prefer dark, damp, warm environments. To prevent infestations, do not leave food or messes lying around, seal up cracks or holes that insects could use to enter your home, and take care of any damp spots in your home, such as leaky pipes or floods quickly.

Water bugs hunt other insects and animals for food. Cockroaches want to eat your food. 

Both can be killed using insecticides, glue traps, and poisoned bait. Only water bugs bite, but their bites are only mildly painful.

FAQs: Roach vs. Water Bug

Here are the answers to more of the most commonly asked questions about dealing with an infestation of roaches or water bugs.