Water roaches might not sound like fearsome pests but if they get into your house, they can cause lots of trouble. What causes these bugs to invade homes and what can you do to stop them?

Let’s explore what attracts water roaches and list the steps you can take to keep them out.

A Simple 5-Step Guide For Getting Rid of Roaches

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Wait! What is a Water Roach?

Three grid illustration of water roach species-American, Oriental, and Smoky Brown cockroaches
Three species of water cockroach: The American cockroach, Oriental cockroach, and smokybrown.

Before we get into the details, we have to straighten this out: a water cockroach isn’t a kind of bug that’s “sort of, but not really,” a cockroach. It is a cockroach. A cockroach of a very specific kind.

Water roaches are a group of roaches known as peridomestic cockroaches—a type of insect that primarily lives outside. In certain regions of the country, these cockroaches have acquired “water roach” as a sort of catch-all nickname (along with “palmetto bugs,” too).

The cockroach species we’re really talking about?

The Oriental cockroach, Smoky brown cockroach, and by far the most common, the American cockroach (for pictures of these roaches see above).

And the species of cockroach we’re not talking about?

The indoor, or “domestic” cockroaches like the Brown-banded cockroach and the German cockroaches below.

Two grid illustration of domestic cockroaches which are not water bugs
The German and brown-banded cockroach. Two domestic cockroach species.

Note: Belostomatidae, a.k.a. the Giant Water Bug or “toe biter” may sometimes be referred to as a water roach, too. These bugs live in water and can deliver painful bites when disturbed, but are not household troublemakers and are probably not the pest you came here for.

Now, without further ado, let’s talk about what causes a water cockroach problem and what you can do about it.

What Causes Them to Come Inside?

Water roaches invade homes for a few reasons, most of which are out of a homeowner’s control. Seriously—they infest homes both clean and dirty, as long as there’s a little food and… the number one reason they move indoors…

Easy access to water.

True to its name, a water cockroach needs lots of water to survive. If a dry spell sucks the water out of the mulch and leaves that cockroaches eat, they’ll start looking elsewhere to quench their thirst—say, those potted plants you dutifully water on the porch.

Just like that, they’ll begin to ignore your personal space and commandeer your home, one area at a time. How disrespectful.

Can Water Roaches Infest Your House?

They might be outdoor bugs to begin with, but once inside, water roaches make themselves at home. Reddish brown to dark brown in color and big—between 1 and 2 inches long, they’re attracted to warm, damp areas, such as the kitchen, bathroom, basement or attic.

They’re fast-moving, good at hiding, and hide behind appliances, in cupboards and in outlets and vents. They can crawl through the hollows between walls and lay eggs beneath baseboards.

You don’t want these bugs around at all, but especially don’t want them building nests in your home. Within weeks of a colony settling in, you could be dealing with dozens more of these intruders skittering around.

Can They Come Up Toilets?

Though it’s true that cockroaches can hold their breath—thankfully, no. Not toilets filled with water, anyway. But leave your house for a season and let your pipes run dry—well, that’s another story. With no water in the pipes and no barrier between your home and the sewer, you could face a nightmare in the bathroom when you return.

Drains, on the other hand, are perfectly acceptable hiding places for these pests. They don’t live in water but they’re known for sneaking into drains for a drink and using the pipes as shortcuts from room to room.

Do They Crawl on You at Night?

Water roaches almost never willingly approach a human, but (rarely) have been known to crawl onto beds at night, drawn by the sweat and skin cells that collect in the sheets. And for what it’s worth, though they’re physically capable of biting people, they’re not often known to do it.

How to Get Rid of Water Roaches

Since these bugs are outdoor insects, preventing them starts outside… in their arena.

Prevention comes down to 4 steps:

  1. Inspect
  2. Seal
  3. Clean
  4. Treat

With a solid plan and dedication to the task, you’ll be like a pest control professional in no time.

Ready? Let’s start with step one.

1. Inspect for entry points.

You’re looking for the tiny cracks, crevices and holes that could provide bugs an easy way to enter your home. Check for gaps around the dryer vent, cracks in the walls, holes in the foundation and torn window screens. Roaches sometimes hide in electrical boxes or near hose bibbs in the wall.

2. Cover and seal every opening you find.

With their small, flat bodies, it’s like cockroaches are designed to be able to squeeze through tight spaces—and they are. To create a solid barrier against these bugs, you’ll have to close up every opening you can find with caulk, steel wool or a mesh screen.

That might seem like a lot of work for a “just-in-case” scenario. But be aware—it takes far more work to get rid of water roaches than it does to exclude them and prevent a problem from happening in the first place.

3. Clean up and organize outside (and inside).

Keeping things as neat and tidy as possible is one of the most important ways to prevent these bugs from finding refuge in your home and mooching off your leftovers. The best-case scenario is keeping them far away from your home in the first place.

Here are a few tweaks to help you achieve this:

  • Spread mulch thinly so that it dries more quickly and disappoints lazy invaders looking for an easy hiding place.
  • Keep things like garbage cans, piles of firewood and landscaping supplies away from your house.
  • Before you bring anything in from the garage or outside, carefully check it for signs of cockroaches. The worst surprise would be giving these bugs a free ride into your own home.

Will they leave if there’s no food?

A water cockroach can live as long as a month without eating but, eventually, it’s going to need some food. These scavengers love finding a plate of leftovers that someone forgot to wrap up. A sink full of dirty dishes is like a midnight snack buffet.

Sweeping, vacuuming, wiping and washing around the kitchen removes their easy food sources. Sometimes, that’s enough to send them looking for new digs.

4. Use pesticides (natural or otherwise) to keep them away.

Once your defense is all set up, you can bolster it with a bit of offense. Pesticides come in many forms but the most effective ones for dealing with a water roach problem (remember to read all labels and precautions) are going to be granular treatments and liquid sprays.

Granular pesticides are great because you can sprinkle them in the mulch and grass and let them work in the background, out of sight and automatically. Sprays can also help treat hard-to-reach areas, like narrow crevices.

One of the best all-natural pesticides is boric acid. You can mix this powder with sugar and sprinkle a thin layer where you think water bugs would enter.

Food-grade diatomaceous earth works wonders as another natural, non-toxic pesticide. You can sprinkle it inside and outside, wherever you want to create a deadly barrier for bugs.


Armed with the steps above, along with a little time and effort, you should be able to stop most water cockroach problem in their tracks.

However, if water roaches have already gotten inside your home, your response will need to be a little different. Learn how to get rid of cockroaches in our guide to facing a cockroach infestation.

Either way, you can do it!


  1. Why do I have cockroaches in my home? (2016) National Pesticide Information Center. Retrieved from http://npic.orst.edu/faq/roach.html
  2. Beriseno, Terri. 10 Cockroach Hiding Spaces. HowStuffWorks. Retrieved from https://home.howstuffworks.com/home-improvement/household-hints-tips/insect-control/10-cockroach-hiding-spots2.htm

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