House centipedes are common in San Diego homes, and if you’ve spotted one darting across your bathroom floor or garage wall, you’re looking at a fast-moving predator that’s been thriving in Southern California since it was first introduced from the Mediterranean region. These long-legged arthropods are drawn to the same things San Diego provides year-round: mild temperatures, coastal humidity, and plenty of smaller bugs to eat.
Why San Diego Homes Attract Them
House centipedes need two things to survive indoors: moisture and prey. San Diego’s coastal microclimates, especially in neighborhoods closer to the ocean like Pacific Beach, Ocean Beach, and Point Loma, provide the ambient humidity these creatures prefer. Even in drier inland areas like El Cajon or Escondido, irrigation systems, landscaping, and poor drainage around foundations create damp pockets that pull centipedes toward structures.
Once near your home, they find their way inside through expansion cracks in concrete slabs, gaps around pipes where they pass through walls, uncapped cement blocks, and floor drains without water traps. During the day, they hide in dark, damp spots: crawl spaces, cardboard boxes stored on garage floors, under sinks, and inside block walls. At night, they emerge to hunt. San Diego’s relatively warm winters mean house centipedes remain active year-round here, unlike in colder states where they go dormant for months.
What They Look Like
House centipedes are about 1 to 1.5 inches long with a yellowish-gray body and three dark longitudinal stripes running along the top. Their most distinctive feature is their legs, which are extremely long, delicate, and banded with dark rings. Those legs fan out from the body almost like eyelashes, giving them a feathery, almost alien appearance. They move fast, which is usually what startles people.
This matters in San Diego because the region is also home to the common desert centipede, a much larger, stockier species that can reach several inches in length. Desert centipedes have shorter, thicker legs, a more robust body, and tend to be tan or brown without the distinctive striping. If the centipede you found looks bulky and muscular rather than wispy and delicate, you may be dealing with a desert centipede, which delivers a significantly more painful bite. House centipedes, by contrast, look fragile and almost translucent.
What They Eat
House centipedes are generalist predators that hunt cockroaches, silverfish, carpet beetle larvae, spiders, ants, and other small household pests. They use their speed to chase down prey and inject venom through modified front legs called forcipules. In a sense, having a few house centipedes around signals that other insects are present, since the centipedes wouldn’t stick around without a food source. Reducing their prey population is one of the most effective ways to reduce centipede numbers over time.
Can They Bite You?
House centipedes can technically bite, but they rarely do. Their forcipules often struggle to pierce human skin, and they have no interest in people. When bites do occur, they typically cause localized pain, redness, and mild swelling that resolves within a few days. The wound often appears as two small puncture marks in a chevron shape. Some people experience a burning sensation, itchiness, or tingling around the bite site.
More serious reactions are uncommon and are associated with larger centipede species rather than house centipedes. Symptoms like headache, nausea, dizziness, or chest discomfort have been documented after centipede bites generally, but these reports overwhelmingly involve tropical species much larger than what you’d find running across your San Diego bathroom tile. Allergic reactions, including anaphylaxis, are possible but extremely rare. For most people, a house centipede bite is comparable to a mild bee sting.
How to Keep Them Out
Moisture control is the single most effective strategy. House centipedes cannot survive in dry environments, so reducing indoor humidity pushes them out or kills them. Run dehumidifiers in basements, garages, and crawl spaces. Use bathroom exhaust fans during and after showers. Fix leaky pipes and faucets promptly, and make sure your home’s grading directs water away from the foundation rather than pooling against it.
Structural exclusion keeps new centipedes from entering. Seal cracks and crevices in your foundation, especially where concrete slabs meet walls. Caulk gaps around pipes, utility lines, and conduit where they pass through exterior walls. Install or maintain water traps in floor drains, particularly in garages and laundry rooms. If you have an unfinished crawl space, consider encapsulating it with a vapor barrier to cut moisture at the source.
Inside the home, reduce clutter that creates hiding spots. Cardboard boxes stored directly on concrete floors are a favorite harborage site. Switch to plastic bins with lids, and keep storage elevated off slab floors when possible. Keeping your garage and basement tidy eliminates the dark, damp refuges centipedes depend on during daylight hours.
Dealing With an Existing Population
If you’re seeing house centipedes regularly, it points to two underlying conditions: excess moisture and an active prey population. Sticky traps placed along baseboards, in closets, and near drains will catch centipedes and also reveal what other insects are present. If the traps turn up cockroaches, silverfish, or ants, addressing those infestations will cut off the centipedes’ food supply.
For heavy infestations, a perimeter treatment applied by a pest control professional around the home’s foundation and entry points can reduce numbers. But without fixing the moisture issue, centipedes will return. The long-term solution is always environmental: dry out the space, seal the entry points, and eliminate the bugs they came to eat. In San Diego’s climate, where outdoor conditions are comfortable for centipedes nearly every month, keeping your home’s interior distinctly drier and tighter than the outdoor environment is the key to keeping them outside where they belong.