Water Bug vs. Cockroach: What’s the Difference?

Although they may look similar, water bugs vs. cockroaches are very different pests. And when you see a fairly large, brown insect crawling around in your kitchen sink, it’s important to identify which type of bug it is so you can eliminate it quickly and safely. 

When you take a closer look, you’ll be able to spot the difference between a water bug vs. a cockroach. Water bugs are primarily aquatic insects and live near water sources, whereas cockroaches are terrestrial and often found near human habitats. Here are some of the main differences and a few similarities between water bugs and cockroaches.

What Is a Water Bug?

A water bug is an aquatic insect in the order Hemiptera. These true bugs tend to live in water, as their name implies, such as freshwater streams and ponds. However, the term ‘water bug’ has sometimes been used to describe certain types of cockroaches, namely the oriental cockroach (Blatta orientalis), which is in a different order.

Water bugs are advanced swimmers, making it easy for them to prey on aquatic insects and crustaceans, with long antennae. You can spot a water bug by its flattened hind legs, large eyes, and brown bodies up to 2 inches long. 

What Is a Cockroach?

You’re probably familiar with cockroaches, which have existed for millions of years. These critters belong to the order Blattodea. There are over 4,500 different types of cockroaches, and several species tend to live in or near human habitats for food and survival. While they may not live in water like water bugs, cockroaches are vulnerable to dehydration and can be found near water sources.

Cockroaches thrive in dark, damp environments, so it’s common for homeowners to find them scurrying around leaky pipes or inside kitchen cabinets with unsecured food.

Water Bug vs. Cockroach

When it comes to telling the difference between a water bug vs. a cockroach, you’ll need to take a closer look at their appearance and behaviors. Let’s compare these two pests to help you determine which type is taking up residence in your home.

Appearance

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Both water bugs and cockroaches are flat, oval-shaped, and usually brown. Water bugs may be tan, brown, or gray, while roaches may be tan, brown, or black. Cockroaches have heads that face downward and legs that look hairy, while water bugs have clawed feet and flat hind legs.

One of the most notable ways to tell the difference between a cockroach and a water bug is by looking at the antennae. Cockroaches have long antennae. Water bugs have what appear to be short antennae but are just their front legs.

Size

Another key difference between a water bug vs. cockroach is their size. Most common cockroaches that you might see in your home or around your yard are about 1 inch long. Water bugs tend to be larger, about 2 to 4 inches long.

Habitat

As expected by its name, water bugs live in aquatic areas. You might find them in a freshwater pond on your property or in a nearby stream or marsh. Tiny hair-like cilia on the water bug’s back legs make it possible for them to travel across water. That’s why finding a water bug inside your home is a rare occurrence, indicating that it’s likely a cockroach.

Cockroaches prefer dark, humid environments. While they need water for survival, cockroaches can’t actually survive by living in water the way water bugs can.

Behavior

Water bugs often fly from one water source to another during their mating season, and they also may fly toward bright lights, like porch lights or lights in the backyard. Water bugs are also solitary insects.

Adult cockroaches can fly short distances, except for oriental cockroaches that are wingless, but most of these species don’t fly very often. Younger cockroaches cannot fly yet, as their wings are not developed. Unlike water bugs, cockroaches are social and live in groups for survival.

Diet

Water bugs depend on hunting for food, and they eat other insects and even small fish and mammals. They have a pointed mouth for hunting. In contrast, cockroaches scavenge for food and aren’t very picky. These pests are happy to eat crumbs on the dining table, food remains on plates in the sink, or leftover kibble in your dog’s bowl. You can ward off cockroaches by keeping garbage and leftovers secure, vacuuming regularly, and closing pet food.

Health Impacts

Water bugs and cockroaches can cause some health issues when they interact with humans. Water bugs, sometimes called “toe-biters”, may inject venom from their legs that feels like a painful bite, like the feeling of a wasp sting, if they feel threatened. Water bug bites can cause swelling and an allergic reaction for some people.

Cockroaches are very unlikely to bite, and bites are not venomous. However, the health issues caused by cockroaches is that they produce allergens in their bodies and feces, which can cause allergic reactions and worsening asthma symptoms for humans. They may also carry and spread diseases

Time of Day

Both water bugs and cockroaches are active at night, which is one reason they’re sometimes confused for each other. Although they are nocturnal, the two species behave quite differently in the dark. Water bugs are often attracted to lights and may fly over from a pond to investigate a porch light or similar home light, but rarely get indoors.

Meanwhile, cockroaches dislike any kind of light and will avoid it if they can. That’s why roaches infamously disperse when you turn the lights on. They tend to stick to dark, indoor places at night.

Water Bug Prevention

Since water bugs are solitary, they don’t infest your home and should not cause any serious problems. However, if they constantly appear in your pool, rain barrels, or even indoor sinks and toilets, you can plan improvements to fix the problem.

The first and best way to keep water bugs away is to fix any leaks and access points to your water sources. That task includes plumbing solutions for dripping water, covers for pools or rain barrels, and pond covers. Otherwise, water bugs shouldn’t be much of a problem.

Cockroach Prevention

Cockroaches are attracted to dark, warm spaces in homes. The best way to stop them is to insulate and seal any access points, including gaps around pipes, broken drain pipes or ductwork, cracks in venting or attic spaces and more. Next, fix any moisture issues in your home, including humid air lingering in an attic or basement. Cockroaches like humid spaces, and the moisture can cause material damage over time. Extra venting and leak prevention can help, too.

Maintaining a clean home also helps control and contain cockroaches. Remove any open sources of food, including open trash, crumbs on the floor or behind appliances, and open, unsealed bags of food like cereal or flour. Finally, set up a few bait traps if you notice cockroaches so you can quickly catch any that make their way inside and prevent numbers from growing.

Cost to Exterminate

If you’re looking to get rid of roaches, the best way to do so is to hire a local bug and insect removal service. Not only do pros have the most effective methods to get rid of roach colonies, but they also know where cockroaches are most likely to be hiding out. Cockroach extermination costs about $100 to $600 per treatment. You may need multiple treatments, depending on the extent of the infestation.

You’re not likely to find true water bugs in your home, but if you are concerned, you can expect to spend around $150 for an initial visit, where the pro can come investigate the issue, or $200 to $600 for pest control service costs.