Why Do Water Bugs Come Out In The Summer?

Everyone loves summer, with its beautiful weather and all the outdoor activities to take part in. But the warmer weather also brings insects, particularly water bugs. If you’re unlucky, it may seem like your home is completely taken over almost overnight. Why is this?

So, why does it seem like water bugs just appear out of nowhere in the summer? Water bugs are cold-blooded creatures that prefer warm weather, much like other insects, and arachnids. When the seasons shift and winter comes in, they tend to retreat and hibernate, which is why you don’t see water bugs in the colder months.

In this article, we’ll discuss why water bugs seem to be more prevalent during the summer months, whether water bugs cause harm to humans, and what to do if you encounter water bugs in your home.

why do water bugs come out in the summer

What are water bugs? How are they different from roaches?

Water bugs are very similar to cockroaches and are often mistaken for them. But knowing the difference means that you’ll be prepared to act if you find them in your home, and you’ll understand the correct method for dealing with them.

  • Appearance – Cockroaches look very similar to water bugs, but there are a few differences that help you tell them apart. Water bugs tend to be darker than cockroaches, ranging from brown to black while roaches are tan to light brown. Water bugs also have large pincers near the mouth, where cockroaches only have antennae. Moreover, you can recognize it as a water bug by its short beak on the underside of its head.
  • Size – Water bugs are usually bigger than cockroaches, growing to up to 2 inches long versus a roach that will usually grow between 1 and 1.5 inches in length.
  • Location – You’ll also find water bugs in different locations than cockroaches. Water bugs prefer to live on the water or in humid, wet conditions, and while cockroaches can survive in water, they prefer not to.
  • Biting behavior – This is the big one that you don’t want to be surprised by. Cockroaches usually scurry away and hide at the first sign of trouble or light, and do not bite humans. Water bugs, on the other hand, can and will bite you if it is threatened or irritated in some way.
Grow Your Yard Tip
Water bug bites release a toxin that, while pretty much harmless to  humans, is certainly a painful nuisance you can live without. However, in some rare cases, someone may have an allergic reaction to the bite, and if that’s the case, quickly seek medical assistance.

Why do I see more water bugs in the summer?

Water bugs can be irritating, but you almost never see them except for in the hottest months, when heat and humidity are at a high. Why do they seem to appear out of nowhere?

The short answer is that water bugs prefer the warm weather of summer over the colder temperatures in the winter. They can’t live in the extreme cold the way warm-blooded creatures can. During the winter, they hide away and hibernate, ready to come back out again in the summer.

But the high temperatures of summer cause a problem for these bugs. Oftentimes, the water that makes up the bugs’ natural habitat dries up, leaving the water bugs to search for cooler, wetter places where they can find food. This is how they find themselves in buildings like your house.

You’ll often find water bugs in places in your house that accumulate water, like kitchens, bathrooms, and basements (especially if it’s unfinished or damp). But the truth is, water bugs can rarely survive for long in a house, since it’s not their natural habitat and food is likely to be scarce.

Grow Your Yard Tip
Keeping your home clean and dry is one of the best things you can do to prevent water bugs from entering your house uninvited. Make sure food and water spills are cleaned and dried quickly, and that your bathroom is allowed to air out after a hot shower. Also, be sure to fix any leaks you may have.

Are water bugs dangerous to humans?

Water bugs hunt by biting their prey and releasing a fluid that paralyzes it. They’re then able to kill and eat the prey while it’s unable to move. They’re able to do this to animals and insects nearly 50 times its size. It’s a grizzly image, and it can certainly make water bugs seem scarier than they are.

Water bugs don’t typically go after humans, and they certainly won’t bite unless they are irritated. Thankfully, water bug bites do not paralyze or harm humans, except in cases of allergic reactions. So even if you do get bit, you can usually treat it like you would any other bug bite.

First, clean the wound with rubbing alcohol, saline or hydrogen peroxide. You’ll want to avoid irritating it by scratching at it, so keep it bandaged and treated with a topical cortisone cream to soothe the area and prevent itching.

Steps to take if you find a water bug in your home:

The bad news is there really isn’t any efficient way to prevent water bugs from entering your home. If they want to come in, they will! But there are several things you can do to make your house less hospitable for them, and some steps to take if you do find a water bug in your home.

  1. Keep your house sealed up. Water bugs can’t climb up smooth, flat walls, so when they’re looking for an entry into your home they’ll look for one low to the ground or near a low window. They can get in through holes in window screens and sections of your house that aren’t properly sealed up, particularly in basements.
  2. Make sure your home is properly ventilated and dry. Water bugs will usually prefer the outdoors, but if you’ve got a wet, leaky basement or your home is humid, it will help to attract bugs. Do what you can to seal up or repair any leaky or wet sections of your house.
  3. Get rid of any standing water or puddles in your yard. Water bugs crave, well, water, so it’s no surprise that a yard filled with puddles and standing water will soon turn into a hotspot for water bugs.
  4. Sprinkle a thin layer of boric acid around the perimeter of your home, especially where you see bug activity. It will kill the bugs upon ingestion and is less toxic for humans than some commercial insecticides. But, be sure to keep out of reach of children!
  5. Use traps to effectively contain bugs. Just like with many other kinds of insects, traps are an effective way to contain water bugs once they’re in your house. Choose a trusted brand that has good reviews, and you’ll find your bug problems will die down quickly. Just be sure to regularly move/replace traps as needed.
  6. Try commercial repellents if preventative measures don’t work. Whether it’s water bug sprays and repellents, insecticides, or more gentle, natural solutions, keep your home regularly sprayed down both inside and outside to deter bugs and kill the ones who enter. If you don’t want chemicals in your home or around your kids, essential oils like peppermint, cedarwood or lemongrass have been used for ages as insect deterrents.

Frequently Asked Questions:

Are water bugs capable of infesting my house?

The thing about water bugs is that they actually look scarier than they are. Water bugs can’t survive and breed in your home the way cockroaches can, and so while they may find their way inside because of the cooler temperatures, they’re not going to cause a major infestation in the same vein of cockroaches.

What are the signs that I have water bugs in my house?

There are a few ways to tell that water bugs have chosen your home for food and shelter, short of actually seeing one crawling around (ew). Water bugs shed their shells periodically, so if you find crunchy hollow shells strewn about the place, that’s another telltale sign. You may also see mysterious black streak marks pop up on floors and surfaces if they’re leaving droppings behind. If you see any of these signs, get to work right away to stop them.


Water bugs emerge every summer from hibernation and flock toward wet and humid places with lots of water. If you live in an area that has water bugs, it’s understandable that you don’t want them in your house. Just remember that, although scary-looking and annoying, they are not inherently dangerous to humans.

Use caution when trying to deal with one, as they do bite, and take steps to prevent them from entering your house in the first place.

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