Saw a big brown water bug crawling underneath your sink? You’ve heard of these pests but might not have cared about them before. Now you want to figure out exactly what you’ve found.
Water bug identification can be a little bit confusing. Not just because there are different types of water bugs. But because there’s conflicting information.
In this short guide, you’ll learn how to tell these insects apart, and what to do to stop them.
Let’s take a look!
Are Water Bugs and Cockroaches the Same?
Yes and no.
“Water bug” is indeed a term many people use to refer to cockroaches. But it usually doesn’t refer to all cockroaches, just the peridomestic roaches (the American, Oriental, and smokybrown roaches) that prefer to live outdoors.
These roaches don’t live in water, but in close proximity to it—in the moist trash dumps, wet sewers, and humid compost around our homes. When these harborages get disrupted or the weather gets too bad, the roaches there may go in search of better conditions, sometimes ending up inside our homes.
There’s another type of water bug however, which isn’t a cockroach—the giant water bug, and it’s not a threat inside your home. Let’s look at that outlier first then ID the cockroach/water bugs one by one.
The Giant Water Bug (Isn’t Interested in Your House)
The giant water bug (Lethocerus americanus) a member of the order Hemiptera, is altogether different from any cockroach you’ve ever seen. Also called the “toe biter” or “electric light bug,” it’s sometimes seen crawling on porch lights, but seldom makes its way inside.
- Size: 2–4 inches in length
- Color: Grayish dark brown, similar to a dead leaf
- Range: Across North America, especially southern Canada and the U.S.
- Habitat: Fresh water, including ponds, streams and the edges of lakes
- Risks: A giant water bug has been known to bite humans when handled.
American Cockroaches (The American Water Bug)
American cockroaches are the insects most commonly referred to as water bugs.
They’re large—in fact the largest pest cockroach in the United States. Both males and females are capable of flight, but are not good flyers. They live in dark, damp places but like other roaches below, don’t live in water. They’re scavengers with terrible eating habits, feeding on trash, waste and other decaying organic material.
- Size: 1.5–2 inches in length.
- Color: Reddish brown with yellow markings behind its head.
- Range: Across the U.S., in areas both urban and rural.
- Habitat: Outdoors in dark, warm, damp environments, such as sewers and drain pipes; indoors in kitchens and bathrooms, near food and water.
- Risks: American cockroaches are known to carry dangerous bacteria and allergens that can contaminate your home. If left unchecked, they can infest in large numbers, cause damage, and put your family’s health at risk.
The American Water Bug Nymph
American cockroach nymphs measure 1/8 inch long when born, and throughout their maturation, look like miniature adults (minus wings). They take 600 days to reach adulthood.
The Oriental cockroach is found in cooler locations with lots of moisture. Unlike other pest roaches, it’s slow-moving, a poor climber, and doesn’t fly.
Its exoskeleton is dark brown to black in color, with a glossy sheen. It has a squatter shape than the American cockroach, and has significantly smaller wings (females’ are almost invisible).
- Size: 1–1.5 inches
- Color: Shiny dark brown or black
- Range: Around the world, especially the northwest, midwest and southern U.S.
- Habitat: Cool, humid environments, like basements, piping, laundry rooms and dumpsters.
- Risks: An Oriental roach can lay 115 eggs per year, so the risk of infestation is high. They can survive on garbage and unsealed food, spreading widely in homes via pipes and cracks in walls. The bacteria they carry can cause stomach illnesses. They also produce a musty stench that’s difficult to eliminate.
The Oriental Water Bug Nymph
Like other roaches, Oriental cockroach nymphs look like smaller, albeit completely wingless versions of the adults. Oriental roach nymphs take about a year to reach adulthood.
Smokybrown cockroaches are strong flyers that are attracted to lights. They sometimes follow lights into living spaces, but more frequently end up in garages, crawl spaces, and attics, where they need a humid environment to survive.
Smokybrowns have long shiny wings and bodies that are uniformly brown.
- Size: 1.25–1.5 inches
- Color: Uniform dark or mahogany brown
- Range: Across the U.S., especially the Southeast
- Habitat: Warm, humid areas, like attics, water meter boxes sewer access openings and roof shingles
- Risks: Smokybrown roaches can spread if left alone, damaging photos and important documents as they feed and lay egg cases. Attics are especially problematic..
Smokybrown Cockroach Nymphs
Smokybrown nymphs are wingless and have distinctive markings—a pair of white stripes on the front half of their bodies and white-tipped antennae. Smokybrown cockroach nymphs take 320 days to reach adulthood.
Not to Be Confused with a Water Bug: The German Cockroach.
Now, a German cockroach is not a water bug by any definition. But these roaches are such widespread household pests that some people lump them all together.
The German cockroach is an indoor species, unlike all of the other bugs on this list. It’s much tinier, capable of hiding in the loose seams of wooden furniture and the electronics inside appliances. They come inside by riding in bags, boxes and clothing.
German roaches multiply extremely quickly and, because they’re so tiny, they could establish a colony before you’ve even seen a roach. They’re considered by many pest control professionals to be the most difficult species to control.
- Size: 0.5 inches
- Color: Light brown, tan or golden with a pair of dark, vertical stripes on its back
- Range: Across the U.S., in close proximity to people
- Habitat: Warm, humid areas of homes, businesses and shared living complexes
- Risks: High risk of infestation. German cockroaches can hide and breed in countless places, allowing them to multiply quickly and spread dangerous bacteria around your home. German roach skins and droppings can trigger allergies and asthma, too.
If you think that you’re dealing with these pests, jump over to our step-by-step guide to getting rid of German roaches.
German Cockroach Nymphs
Baby German cockroaches look like miniature versions of the adults but lack wings.
You’ll notice the pair of dark stripes running from head to rear cerci. A German roach nymph that’s just hatched or molted might appear gray or white. When it’s born, it’s only about the size of a grain of rice. It takes a mere 60 days to reach adulthood, increasing the risk of a cockroach infestation.
While roaches aren’t the only kind of water bug, they’re usually the ones that cause problems. They’re also (for most folks) not just any kind of roach, but one of several outdoor species. Each with unique risks and challenges.
Water bug identification is an important first step. You’ll want the next to be about action.
Head over to our water bug control guide to learn how to get rid of different types of water bugs permanently. There, we’ll show you how to create a roach-free home in four simple steps. To help you say—
Goodbye, water bugs!
Frequently Asked Questions
Are water bugs and roaches the same thing?
A true water bug—the giant water bug—isn’t a cockroach at all. However, most people who talk about water bugs are actually talking about one of several species of outdoor cockroaches (see above).
What’s the difference between a water bug and a roach?
Water bugs and roaches are different types of insects. The giant water bug is the largest “true bug” and a member of the order Hemiptera. It’s an aggressive, aquatic predator but not a household pest. Don’t handle one, though; you definitely don’t want a painful water bug bite.
A roach, on the other hand, is a potentially harmful pest in homes and businesses. It’s an insect of the order Blattodea. It inhabits damp, humid environments but doesn’t live in water.
Do water bugs eat roaches?
Giant water bugs, like Lethocerus americanus, hunt many kinds of small prey, from tadpoles and fish to crustaceans and snakes. They also eat other insects, though cockroaches aren’t a common staple of their diet because roaches live on dry land.
How big are water bugs?
Giant water bugs grow as long as 4 inches, with large front legs and a wide, oval-shaped body. The cockroaches typically called “water bugs” range from 1–2 inches in length.
- Gray, Betty. Giant Water Bug. Texas A&M: Beneficials in the Garden & Landscape. Retrieved from https://aggie-horticulture.tamu.edu/galveston/beneficials/beneficial-55_giant_water_bug.htm
- Choate, Paul M. (2019) Giant water bugs, electric light bugs. University of Florida Entomology. Retrieved from http://entnemdept.ufl.edu/creatures/misc/bugs/giant_water_bugs.htm
- 2019 State of the Cockroach Control Market (2019) Zoecon/Central Life Sciences.
- Giant Water Bug. (2020) U.S. National Park Service. Retrieved from https://www.nps.gov/articles/giant-water-bug.htm
How can you tell a cockroach from a water bug? ›
The only roach similar in size to a waterbug is the American roach, but you can differentiate it from a waterbug by its yellowish figure-eight pattern on the back of the head. Cockroaches are typically light tan to dark brown in color, while waterbugs are tan to black, but their colors won't be of much help.Why are cockroaches called water bugs? ›
Although many people refer to various cockroach species as waterbugs, the true water bug is an aquatic insect classified under the order Hemiptera. Water boatmen and water scorpions are true bugs that live in water. Their legs are used as paddles to move through water.Are water bugs and cockroaches different? ›
Water bugs are most commonly confused with cockroaches. The two insects bear a certain resemblance to each other, but there are key differences. Water bugs pack a powerful bite, but they are not the pest that cockroaches are.What is a water bug look like? ›
Water bugs are typically grayish or brown in color with an oval-shaped body but they don't have the identifying antennas of a cockroach. The one cockroach that is commonly mistaken for a water bug is the Oriental cockroach.Do water roaches fly? ›
It's also important to note that most cockroaches and water bugs can fly, says O'Neal. However, the oriental cockroach, which is most commonly mistaken for a water bug, cannot. In fact, female oriental cockroaches don't even have wings, according to Changlu Wang, Ph.Do water bugs fly? ›
Water bugs fly between bodies of water during mating season, and they may be attracted to lights on porches or in parking lots.What do water bugs eat? ›
Behavior and Feeding. Giant water bugs prey on a surprising variety of aquatic life, including tadpoles, small fishes, insects, and other arthropods. Some are known to kill prey many times their own size. Grasping victims by “raptorial” front legs, they inject venomous digestive saliva into their prey.Do Water Bugs have 6 legs? ›
Insect Size and Appearance
Oriental and American Cockroaches have the typical external shell that is either a shiny black or reddish brown while Waterbugs. They have 6 six legs and a pair of antennae. Water bugs have a much varied appearance coming in brown, greenish brown.
Waterbugs are attracted to damp, moist areas, and they are also very attracted to old food and garbage. In other words, if you're noticing waterbugs in your home, that's probably an alarm that you aren't cleaning enough.Where do water bugs come from? ›
Often, they are found in places where organic material is decomposing, like under objects that are outside, especially trash cans, or in mulch or compost. These water bugs are also attracted to sewer pipes and septic tanks. Anywhere dead plants and leaves have collected and are rotting, water bugs may be found.
Is an American cockroach a water bug? ›
What is An American Cockroach? The American cockroach is the largest of the house-infesting roaches and a major pest in the United States. It's also commonly known as the water bug, the Bombay canary or the palmetto bug.What are the different types of water bugs? ›
Giant water bugsWhat bug looks like a cockroach? ›
Beetles look similar to cockroaches but have shorter legs and antennae. Because both types of bugs can have similar coloring, it can be easy to confuse beetles for cockroaches and vice versa.Do water bugs play dead? ›
Water bugs also hide or play dead, but they're known for biting as well. When a water bug bites, it injects digestive enzymes and extracts liquefied tissue.Can water bugs jump? ›
There are many different large water bugs, but the only water bugs that jump are known as water striders or pond skaters. These bugs can jump several inches in the air and can annoy pool-goers by skating and jumping across pool surfaces, drawing nearby bug predators with their very presence.Do water bugs make noise? ›
Because the insect lives underwater, most of the sound is lost when transferring from water to air. However, the water bug's song is still loud enough to be heard by a person walking along the banks of a pond or river. Most of the loudest animals on Earth are also the largest.What bug looks like a cockroach but isn t? ›
Cricket. Crickets (family Gryllidae) are sometimes mistaken for cockroaches but there are important differences between the two. Crickets range in color from brown to black, much like some cockroach species. They also have long antennae.What colour is cockroach blood? ›
Cockroaches do not have red blood because they do not use hemoglobin to carry oxygen. They do not carry oxygen in their blood stream either. Most cockroach's blood is colorless.What does cockroach poop look like? ›
Roach droppings look like specks of pepper, coffee grounds, or dark grains of rice. The size of the feces is directly related to the size of the cockroach. Bigger insects produce larger droppings.Are water bugs poisonous? ›
Water bugs will bite people if they are carelessly handled. They will also sometimes bite people as they wade through ponds and streams, earning them the nickname "toe biters." Giant water bugs are not dangerous to humans, but they inject a mild poison into the prey that they capture.
Can water bugs climb walls? ›
It's important to check exterior walls, windows and doors, too. You're looking for openings just half an inch wide through which water bugs can crawl.Are water bugs scared of light? ›
Both cockroaches and water bugs come out at night to forage for food and water. However, unlike cockroaches who are scared of bright lights, water bugs are attracted to them and sometimes stray into houses at night.What looks like a cockroach but isn t? ›
Some bugs that look like roaches but aren't include crickets, water bugs, and certain beetles.Why am I getting water bugs in my house? ›
Waterbugs are attracted to damp, moist areas, and they are also very attracted to old food and garbage. In other words, if you're noticing waterbugs in your home, that's probably an alarm that you aren't cleaning enough.What kills water bugs instantly? ›
Use borax or boric acid—These natural elements will destroy a water bug's digestive tract, killing them from the inside out. Sprinkle a thin dusting of borax or boric acid in your basement, under sinks, and other areas where you've seen water bugs.Are there bugs that look like cockroaches? ›
Ground beetles are one of the few bugs that look like cockroaches due to their similarities and are often mistaken with them. They have the same deep red or brownish exterior and a wide, winged frame. For this reason, differentiating ground beetles from cockroaches can be a challenge.