How to Tell Cockroaches and Waterbugs Apart

Waterbugs vs. Cockroaches

What is a waterbug?

Although many people call various cockroach species "waterbugs," true water bugs belong to the order Hemiptera and are aquatic insects. Examples include water boatmen and water scorpions, which use their legs as paddles to swim. Other true water bugs, like water striders and pond skaters from the Gerridae family, rely on surface tension to stay afloat rather than swimming.

A commonly mislabeled "waterbug" is the oriental cockroach (Blatta orientalis), which is not aquatic and is actually native to Africa. These shiny, dark brown, or black insects are often mistaken for true water bugs. Oriental cockroach nymphs are smaller than adults, and adult males are smaller than females. Unlike true water bugs, oriental cockroaches have underdeveloped wings and cannot fly.

Understanding the key differences between true water bugs and oriental cockroaches can help you correctly identify these pests and address them effectively.

Appearance

What do waterbugs look like?

Giant water bugs are large, predatory insects measuring 2 to 4 inches long. They have a flattened, oval-shaped body in dark brown or gray, with pincer-like front legs for catching prey and oar-like hind legs for swimming. Their short antennae and overlapping wings form an "X" pattern when at rest, giving them a distinctive appearance.

Identifying Oriental Cockroaches

Oriental cockroaches are easy to identify by their shiny, dark brown to nearly black exoskeleton and broad, flattened bodies. Adults are about 1 to 1.25 inches long, with males sporting short wings that cover most of their abdomen and females appearing almost wingless, with only small wing pads. Unlike waterbugs, oriental cockroaches lack pincer-like front legs and oar-like hind legs. Their uniform coloration and preference for damp areas, like basements and sewers, set them apart from other cockroach species.

Habitat

Where do waterbugs live?

Water bugs, especially giant water bugs, thrive in freshwater environments like ponds, lakes, marshes, and slow-moving streams. They prefer still or sluggish waters with abundant aquatic vegetation, where they can easily hunt for prey. Giant water bugs are also capable of flying and may be drawn to artificial lights, sometimes ending up around swimming pools or residential areas at night. Their natural habitat offers both food and safe breeding grounds, as well as shelter from predators.

Where are oriental cockroaches found?

Oriental cockroaches prefer warm, damp environments and are commonly found in sewers, basements, cellars, and crawl spaces. They favor dark, sheltered spots close to the ground, often hiding under debris, leaves, or trash cans. While they usually live outdoors, they can enter homes through gaps under doors, air ducts, or utility lines, especially in search of food or moisture. Indoors, they tend to stay on lower floors, frequently found in bathrooms and kitchens where water sources are abundant.

Diet

What do waterbugs eat?

Giant waterbugs are skilled predators that primarily feed on aquatic animals like small fish, tadpoles, frogs, and other insects. They use their powerful forelegs to ambush prey, lying in wait among vegetation before quickly grabbing it. Once captured, they pierce their prey with needle-like mouthparts and inject digestive enzymes to liquefy the tissue, allowing them to suck up the resulting fluid. This hunting technique makes them highly effective in their freshwater environments.

What do oriental cockroaches eat?

Oriental cockroaches are scavengers with a diverse diet, mainly feeding on decaying organic matter like rotting food, plant material, and garbage. They thrive in damp, unsanitary areas like sewers and basements. In addition to decomposing materials, they will consume a variety of items, including bread, meat, vegetables, grains, and even non-food sources like paper and leather. Their adaptability allows them to survive on nearly anything, but they need water to thrive and can only survive for about two weeks without it.

Danger

Do waterbugs bite?

While most waterbugs aren’t aggressive towards humans, giant water bugs, also known as toe-biters, can bite when threatened. Their bite is sharp and painful, delivered through needle-like mouthparts that can cause significant discomfort. Although not usually medically dangerous, giant water bug bites can lead to localized pain, swelling, and in some cases, allergic reactions. If bitten, clean the wound, apply ice, and use over-the-counter pain relief. Seek medical attention if you experience severe symptoms or signs of an allergic reaction.

Do oriental cockroaches bite?

Oriental cockroaches can bite humans, but it's rare and usually happens when food is scarce or during large infestations. Their bites may cause minor irritation and a red welt, but they’re not typically dangerous unless an infection occurs. The bigger concern with oriental cockroaches is their ability to carry harmful bacteria from unsanitary environments, which can contaminate food and surfaces, potentially causing illnesses like food poisoning or allergic reactions.

If you’re unsure whether you’re dealing with cockroaches, waterbugs, or other pests, professional pest control can help identify the issue and provide effective solutions. Contact Orkin for a customized treatment plan to help protect your home against cockroaches.

More Cockroach Facts

What does a cockroach look like?

Cockroaches are typically oval-shaped with flat, reddish-brown to black bodies, long antennae, and six legs.

Difference Between a Cockroach and a Palmetto Bug

Palmetto bugs are a type of cockroach, specifically the American cockroach, known for their large size and ability to glide.