Some pest questions take a little extra explanation—like the difference between a roach and a waterbug. Though it may come as a surprise to some, water bugs and roaches are different, and we’ll tell you just how here.

So. Water bug vs. roach? Let’s go.

The Water Bug That Started it All

Illustration of a giant water bug partially submerged in a pond
Giant Water Bugs are true bugs (not roaches) that live in water, and are seldom household pests.

Any discussion about water bugs should include at least a mention of Belostomatidae, the Giant Water Bug (otherwise known as the toe biter or electric light bug), a type of insect common in many ponds and streams.

Huge, predatory, and known for biting people who get too close, this is unquestionably a water bug, unquestionably not a species of cockroach—and (we’re guessing) probably not the critter you had in mind.

For that, we need to look at some other big, bad bugs, at least one of which may be the one you’re looking for.

Water Bug vs Cockroach: Here’s How and Why They’re Different

The Water Bugs

Three grid illustration comparing three outdoor cockroaches: the American, Oriental, and Smoky Brown species
Water bug that looks like a cockroach? The American, Oriental, and Smokybrown cockroach are also known as waterbugs.

Consider the bugs above and take your pick. Is it a roach or waterbug? You’d be right either way.

Because depending on where you live, they’re all considered water bugs. And they’re also all cockroaches.

“Water bug” it turns out, isn’t a particular kind of bug, but a regionally-inspired nickname for a certain type of cockroaches—peridomestic roaches that prefer to live outdoors but infest homes when they choose or need to.

The “water bug” nickname is most frequently used to refer to the American cockroach (the big cockroach on the left), but is sometimes used to refer to the Oriental cockroach and the Smoky brown cockroach, too.

So if all water bugs are roaches (except for the Giant one), would all roaches be waterbugs, too?

Well, no.

The Roaches

Two grid illustration of domestic cockroaches which are not water bugs
The German and Brown-banded (domestic) cockroach.

Because in addition to peridomestic roaches, there are domestic roaches like the Brown-banded and German cockroach which almost never live outside, specifically target human homes, and wouldn’t be referred to as water bugs by anyone familiar with their habits. They’re just roaches.

Some Facts About Water Bugs and Roaches

Ways to Tell a Water Bug & Roach Apart

The most dependable way to identify a cockroach/water bug is to compare a live or dead one to an image like the ones above. But it’s not the only way.

There’s one difference between a cockroach and waterbug you can notice easily, even from a distance. And two more you can deduce from the evidence they leave behind.

  • Waterbugs are Bigger. Waterbugs are bigger—sometimes much bigger than domestic cockroaches. The American cockroach/waterbug for example, can grow over two inches long. While the tiny German cockroach (a domestic roach) rarely grows larger than the surface of a penny.
  • You May Find Water Bugs and Cockroaches Infesting Different Places. Water bugs thrive in areas with lots of moisture, and unlike domestic roaches which love the food source in your pantry, seek out humid areas like your bathroom or basement floor. Based on where you spot them, you can make a pretty good guess about what kind of bug they are.
  • Waterbug Poop is Different. You don’t actually need to see a water bug/roach to know that they’re around. They leave egg cases, discarded shells, and poop where they’ve been living, and it’s often easy to find. The poop of a domestic cockroach will be tiny, looking something like black pepper or coffee grounds. Water Bug poop on the other hand, will be be bigger and often cylindrical in shape.

Can Water Bugs Infest Your House the Way That Indoor Roaches Do?

Despite being outdoor insects, water bugs do infest houses.

They usually come inside if they’re searching for food or trying to escape harsh, dry conditions. Outside, they live in mulch, tall grass, tree hollows and, sometimes, dumpsters or utility boxes. Inside, they prefer the bathroom and kitchen but they’ll also infest humid attics or damp basements.

Can Water Bugs Come Up Through Toilets?

No, fortunately. So long as your throne hasn’t gone dry from lack of use, it’s safe from marauding water bugs.

However, other drains are not as safe. Sink, bathtub and shower drains let water bugs climb through the pipes, straight into the bathroom or kitchen. Oriental cockroaches are one of the biggest culprits of this behavior, hiding in drains and moving from room to room through the piping.

Is It Normal to Find a Water Bug/Roach in Your House?

While it’s not normal to find cockroaches and waterbugs in your house, it’s definitely a common problem in many parts of the U.S. The larger water bugs seem to pop up everywhere in the South, invading cupboards, drains, pantries and more.

The commonness of cockroach infestations makes them simply a part of life in many areas. That fact could contribute to the use of the nickname “water bug” as a more polite way to speak about a “roach infestation.”

What Causes Water Bugs in Your House?

Water bugs (the cockroach kind) are attracted by all kinds of food, from cooking scraps and loosely wrapped desserts to the stuff that builds up in the garbage disposal and breaks down in your compost pile.

Sometimes, water bugs come indoors because they’re thirsty. These insects are sensitive to dehydration and, though they can go weeks without eating, they need lots of water to survive.

Tips & Solutions for a Water Bug Cockroach Problem

Water bugs can become a major problem if they’ve gotten into your home. They’ll contaminate food and spread dangerous bacteria around your house. Don’t let their nickname fool you: the faster you can get rid of these harmful pests, the better.

How Do You Get Water Bugs Out of Your House

You have 3 choices when it comes to getting rid of water bugs:

1. Clean up and hope they leave.

Keeping everything sparkling-clean can go a long way toward getting rid of roaches. But in some places, water bugs just seem to be everywhere, even in the cleanest of houses. In those cases, it takes a bit of offense, too.

2. Use baits or natural cockroach killers.

Chemical baits or natural roach repellents can get rid of water bugs in most cases. Boric acid is one solution that kills water bugs instantly. When you’re taking them on DIY-style, persistence and patience are the keys to success.

3. Call in backup: hire a professional.

If you’re facing a large infestation of water bugs, calling your local pest control service is the best idea. They have the tools to get rid of the problem as quickly as possible.

Conclusion

Water bugs are a fact of life for many people and despite their reputation for scurrying back into the darkness at the first sign of a person, they can pose real risks to your family.

The real water bug vs. roach question should be: How do I get rid of them?

We’ll take you step-by-step through the process of getting rid of cockroaches so you can keep your home bug-free.

You can do it!

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