Are House Centipedes Good or Bad to Have Around?

Meet the house centipede

Here is how to read the signs and decide whether to live with them or do something about it.

The house centipede is the long-legged, yellowish-gray creature that darts across the basement floor or appears in the bathtub at night. Adults have 15 pairs of very long legs, two long antennae in front and a matching pair of long legs at the rear that make it hard to tell which end is which. They can run surprisingly fast for their size.

Unlike most centipedes, this species can live its whole life indoors. It likes cool, humid places: basements, crawlspaces, bathrooms, laundry rooms and the space under a utility sink. It hides by day under boxes, in floor drains and behind baseboards, then comes out after dark to hunt.

House centipedes are also long-lived for a household arthropod, often surviving several years. Young ones hatch with only a few pairs of legs and add more with each molt, so finding small, short-legged centipedes is a sign they are breeding in the house.

The case for leaving them alone

House centipedes are predators, and their menu is a list of pests most people would rather not have. They catch prey with their legs and venomous front claws, then eat it on the spot. That steady hunting means a few centipedes in a basement are doing some free pest control.

• Silverfish and firebrats, which damage paper, book bindings and starchy fabrics
• Young cockroaches
• Spiders and spider egg sacs
• Carpet beetle larvae, which chew wool and natural fibers
• Termite swarmers and ants that wander indoors
• Bed bugs, though centipedes will never control an infestation

So when are house centipedes bad news?

One centipede in the bathroom every few weeks is not a problem. Seeing several a week, finding them upstairs in bedrooms, or spotting young ones in different sizes means a breeding population has settled in, and that population needs two things to survive: moisture and food.

The moisture side often points to a real building issue, such as a damp basement, a leaky foundation wall, a dryer vent that dumps humid air into a crawlspace, or a bathroom without a working exhaust fan. The food side means other insects are living in the house in numbers you are not seeing. When we find lots of centipedes, we usually also find silverfish, spiders or roaches in the same areas.

Do house centipedes bite people?

House centipede bites are rare. They are not aggressive and would much rather run. A bite usually happens only when someone grabs or traps one, such as pressing it against skin while picking up a towel. The jaws of a house centipede are small and often cannot pierce thick skin.

When a bite does occur, people commonly compare it to a mild bee sting, with brief pain and local swelling. Anyone who has trouble breathing, swelling of the face or throat, or another severe reaction should call 911 or seek medical care right away.

Why basement centipedes keep showing up in bathrooms

Centipede in bathroom sightings usually trace back to the basement. Floor drains, tub drains and gaps around plumbing that runs between floors give them a path upward, and bathrooms offer the humidity they crave. They also fall into slick tubs and sinks while hunting and cannot climb back out, which is why you so often find them stuck there in the morning.

The fix starts below. Running a dehumidifier in the basement to keep humidity around 50 percent, sealing gaps around pipes, and moving cardboard boxes off the floor onto shelves all make the space less livable for centipedes and their prey.

How to get rid of centipedes for good

Spraying the centipede you see does almost nothing, because the population lives in hiding. Lasting control means changing conditions: reduce moisture, remove clutter where they hide, seal cracks along the foundation and around basement windows, and clear leaf litter, mulch and stored wood from against the outside walls.

Then deal with the food supply. If silverfish or spiders are present, those need attention too; our silverfish control service often goes hand in hand with centipede work. Targeted treatments at entry points and in voids help when populations are high, and our centipede and millipede control pairs that work with moisture and sealing recommendations.