It’s Alive! 4 Pests That Are Signs Your Crawl Space Might Be Too Moist

Moist and overly wet crawl spaces are common problems. Homeowners often rely on the presence of mold and the overall feeling of humidity in the air to tell whether their crawl space is too moist; however, there is another potential sign of moisture and humidity that you may be overlooking. Certain pests, ones that absolutely love moisture, may start appearing in your home if they find your crawl space to be a good source of water. Here are four key pests that may signal that your crawl space is too moist.

Norway rats

Although all rats and mice need water, Norway rats are particularly fond of water. This may be why they are sometimes known as sewer rats. These rats are about nine inches long with a tail that is slightly shorter than their body. Their hair is brown or gray and rather fluffy. Their undersides are often white or slightly lighter in color than the rest of their body.

Signs of Norway rats include black or brown, cylinder-shaped feces. You may also see gnaw and claw marks around your baseboard and door frames. These rats will chew through anything, including electrical wires, so they can do a lot of damage to your home if allowed to reproduce unchecked. While trapping and baiting may decrease their numbers, new rats may keep venturing into your home until you take care of what is attracting them: crawl space moisture.


These bugs have a rather gross appearance, with silver-gray skin, cylindrical bodies, and large antennae. They are often seen in bathrooms and kitchens, but they may invade your crawl space if it is too moist as well. Silverfish have been known to eat the backing of wallpaper, pages from books, and even important documents. They cannot resist the starch that these items contain. You won't have much luck getting rid of silverfish until you get rid of the moisture that they love so much.

German cockroaches

German cockroaches are typically about a half to one inch long with brown or black bodies. These bugs are more than a nuisance; they are also known to spread disease. They may track salmonella and other bacteria over your food, causing you to experience food poisoning when you then eat that food. Many people are also allergic to the proteins on a cockroach's skin, which leads to sneezing, itching, wheezing, and other respiratory symptoms.

Cockroaches reproduce very quickly and are very difficult to get rid of. A pest control expert will want to apply insecticides in order to keep the bugs at bay, but controlling moisture is an important long-term strategy, too.

Carpenter ants

If you have had a problem with moisture in your crawl space for a while, some of the wood in your home may have begun to deteriorate. Mold and rot make the world a very appealing place to carpenter ants. These large ants can be up to half an inch long. They may be black or reddish brown in color. Although they do not feed on the rotting wood, they do build their nests within it, which can sacrifice the wood's structural integrity.

Getting rid of carpenter ants can be difficult since their nests are located within the moist wood. Drying out your crawl space is an important first step, as it will keep any remaining wood in your home dry and less appealing to these ants.

If you have noticed any of the pests above lingering around your home, crawl space moisture is an issue you should look into. There are many crawl space waterproofing companies, such as Central Penn Waterproofing, that will provide services such as leak sealing, reinsulating, and encapsulation to keep your home dry and pest-free in the future.