House Centipedes in Idaho: What They Are, Why They're in Your Boise Home, and How to Stop Them (2026 Guide)

You flip on the bathroom light and something the size of a quarter darts across the tub. Fifteen pairs of legs. Two long antennae. Yellowish-gray with dark stripes. Gone before you can grab a shoe.

That's a house centipede. And in July and August across the Treasure Valley, we get more calls about this bug than almost any other. They love the cool, dark, slightly damp corners of Boise homes when the outside temperature climbs past 95°F.

Here's the good news right up front. House centipedes are not dangerous. They don't damage your home, they don't spread disease, and they'd rather sprint away from you than come near you. They're actually hunting the pests you don't want, like spiders, silverfish, and roaches.

The bad news? If you're seeing them, you almost certainly have moisture problems and a bigger pest ecosystem in your walls. This guide covers what to look for, why they're there, and how to make your home a place they don't want to live.

If it's short, fat, slow, and dark brown or black, that's probably a millipede (or a different ground centipede species from the yard). House centipedes are always long-legged, pale, and lightning fast.

The house centipede (Scutigera coleoptrata) is the only centipede species you'll routinely find indoors in Idaho. Once you know the look, you'll never confuse it with anything else.

Do not confuse a house centipede with a giant desert centipede (Scolopendra). Those are 4 to 6 inches long, thick-bodied, reddish-brown, and their bite is genuinely painful. Giant desert centipedes are rare in the Treasure Valley but do turn up in southern Idaho and Owyhee County. If you see one, do not handle it. Call us at (208) 297-7947.

No. House centipedes are not dangerous to humans, dogs, or cats. They are venomous in a technical sense (they inject venom into the small bugs they hunt), but their fangs are too small and weak to reliably break human skin.

In the rare case a house centipede does bite a person, it feels like a mild bee sting and clears up in a few hours. There's no medical concern, no need for antivenin, and no risk of infection beyond what you'd expect from any minor skin irritation. If you have an unusually strong reaction, call your doctor, but that's the same advice for any bug bite.

They also don't damage your home. They don't chew wood like carpenter ants, they don't destroy fabric like carpet beetles, and they don't contaminate food like roaches. They're just... unsettling to look at.

In our 10-plus years serving the Treasure Valley, when we treat a home for house centipedes we almost always find a plumbing leak, a poorly-sealed crawl space vent, or a bathroom fan that isn't venting properly. Fix that first and half the problem goes away on its own.

House centipedes need two things to survive indoors: moisture and prey. Take away either one, and they leave (or die). If they've moved into your home, both are present.

Boise summers create a specific problem. Outside, the air is bone-dry and often over 100°F. House centipedes lack the waxy shell coating that most bugs have, so they dry out and die within hours in that heat. Your basement, crawl space, or bathroom is a lifeboat. Cool, humid, dark, and full of other bugs to eat.

Here's the part most homeowners miss. Centipedes are hunters. They don't eat crumbs or bread or garbage. They eat other bugs, live and moving.

If you have a healthy population of house centipedes, you almost certainly have a healthy population of at least one of these:

House centipedes stick to five specific zones. If you're seeing them in one of these, that's the ecosystem to treat.

Killing the one you see doesn't fix anything. Ten more are behind the drywall, and more are coming in from your yard. To actually solve this, you have to attack all three legs of the stool: moisture, entry points, and prey.

This is 60% of the fix. Without water, house centipedes can't survive more than a day or two indoors.

The techniques in our rodent-proofing guide work perfectly for house centipedes too. Anything that keeps a mouse out will keep a centipede out.

Centipedes come in through the same gaps other pests use. Sealing them cuts off the pipeline.

This is the piece homeowners can't easily do themselves. Even a clean, dry home has some spiders, silverfish, and small ants in the wall voids. A single quarterly perimeter treatment kills those out and starves the centipedes.

This is exactly what our general pest control service does. We treat the exterior perimeter, hit the entry points, and knock down the whole ecosystem in one visit. Centipedes usually disappear within 2 to 3 weeks of the first treatment, not because we sprayed them directly, but because there's nothing left to eat.

For a deeper look at the full-home approach, see our pest-free home guide.

A few common mistakes we see in Boise homes:

You can absolutely handle one or two centipedes a summer on your own. Squish it, dry the tub, move on with your day.

Call in help when any of these apply:

Our $49 initial service is built for exactly this kind of problem. Here's what happens on the first visit.

House centipedes tell you your home has a pest ecosystem worth treating. The good news is that one visit takes care of the whole thing (centipedes, spiders, silverfish, ants, all of it) for just $49 to start.

We serve Boise, Meridian, Eagle, Nampa, Caldwell, Kuna, Star, and the rest of the Treasure Valley. Call (208) 297-7947 or book online. Same-day service available if you call by noon.