What Is a Water Bug?

What Is a Water Bug?

Have you ever been confused about the difference between water bugs and cockroaches? The distinction can be important when you’re met with one in the wild or dealing with an infestation in your living space. Are water bugs cockroaches? The answer is two-fold: yes and no. Colloquially, people speaking about water bugs are often talking about cockroaches, but a true water bug is not a roach.


A true water bug is from the family Belostomatidae. These bugs are called giant water bugs, toe-biters, or electric-light bugs. The species most often found in the United States are usually around two inches long but can be up to four inches long. Giant water bugs live in freshwater throughout the country but are not as commonly found in southern states. These predators move very fast and deliver painful bites to humans when disturbed. Unlike cockroaches, giant water bugs do not live indoors.


Giant water bugs look like large, flat, brown beetles with clawed front legs used for attacking and holding onto prey. They also have sharp mouthparts for piercing their prey and injecting venom. You may see male water bugs carrying dozens of eggs on their back while swimming around, but remember to keep your distance as these bugs have an intensely painful bite.


In some areas of the U.S., certain cockroaches are referred to colloquially as water bugs. Most often people are referring to peridomestic cockroaches that typically live outside and only venture indoors on occasion. In contrast, the German cockroach and brown-banded cockroach are domestic cockroaches. They exclusively live inside human dwellings since they have evolved to be dependent on our food and waste for survival.

The three cockroaches most often referred to as water bugs are the American cockroach, the Oriental cockroach, and the smoky-brown cockroach. 


These roaches are big (though not as big as water bugs), typically measuring 1 to 2 inches in length (not including antennae), which makes their presence quite startling. American cockroaches are light to medium brown in color and usually have a yellow figure-eight pattern on their head. They prefer moist, shady environments outdoors like mulch, drainage areas, and sewers. Often, American cockroaches will gather in harborage areas like wood piles or discarded boxes around the perimeter of your home and then eventually find their way inside. American cockroaches can also fly short distances. These roaches will eat anything from paper towels to pet food and dead insects.


Oriental cockroaches are darker in color than other species and are usually about 1 inch long. These cockroaches move more slowly than American cockroaches. They seek out dark, moist places and may also prefer cooler spots like basements and tile floors under appliances. These roaches are known for transmitting gastrointestinal diseases like food poisoning and secrete a musty, foul odor.


The smoky brown cockroach resembles the American cockroach, but they are usually a darker shade of brown, have a shiny appearance, and lack the yellow figure eight markings on the head. Smoky brown cockroaches are strong fliers and are very prevalent in regions with high humidity. These pests seek out wooded areas, feed on decaying matter, and often enter the home accidentally on a piece of firewood or through something carried in from the garage.


Many people only associate cockroaches with more common, domestic roach species (like the German cockroach). “Water bug” cockroaches—the American, Oriental, and smoky brown—are more likely to live outdoors and don’t usually cause as much of an infestation. And giant water bugs are not found indoors, as they thrive in freshwater. Here’s a quick reference guide to help tell the difference between the three:

Of course, any cockroach species should not be ignored when you find them in your living space. If they’ve made their way inside your home and found food sources, they are likely to stay.


True giant water bugs do not venture indoors, but “water bug” cockroaches do. True water bugs live in freshwater where they feed on fish, tadpoles, and other creatures. If you were to see a true water bug indoors, it was probably brought there by a human—either accidentally or on purpose. Some people even keep them as “pets” in an aquarium. 

The colloquially named “water bug” cockroaches on the other hand (American cockroaches, Oriental cockroaches, and smoky brown cockroaches) do occasionally venture indoors. Although these cockroach species prefer to live outdoors, they have no problem adjusting to life on the inside when provided with food sources and moisture.  

When conditions are less than ideal outside, these “water bugs” will venture indoors in search of moisture, food, or warmth. Their need for moisture is also why they are often found in pipes, drainage areas, bathrooms, and kitchens. 

Cockroaches may also come into the home accidentally. If they are living in your yard, garage, or around the perimeter of your home, they can be unwittingly transported inside via firewood piles, used clothing and furniture, or even hitch a ride in on a pet.


Getting rid of cockroaches can be quite an ordeal, which is why it’s best left to the professionals. All species of cockroaches are known to spread disease, cause allergic reactions, and create waste. Our pest control experts are armed with the knowledge, products, and experience needed to take care of these pests thoroughly and reliably.

At Joshua’s Pest Control, we don’t take “water bugs” lightly. Our friendly field experts use a combination of products and barrier treatments to ensure your home is rid of these pests. Contact us today for help.


Author Bio

Courtney Enzor has worked in the pest control industry for about a decade. From helping you build a fly trap to giving you the best tips for identifying various bugs, she loves answering all your pest-related questions and sharing her pest-related expertise through writing. At the end of the day, she hopes her content will help people avoid mishaps and keep families happy and healthy!