| Species | Size | Legs | Habitat | Risk |
|---|---|---|---|---|
| House centipede (Scutigera coleoptrata) | 25–50 mm | 15 pairs, very long with bands | Basements, bathrooms, damp rooms | None — beneficial predator |
| Stone centipede (Lithobius spp.) | 20–35 mm | 15 pairs, short, reddish-brown | Garden soil, under stones | Rare pinch outdoors only |
| Soil centipede (Geophilomorpha) | 50–100 mm | Many pairs (31–177), thread-like | Deep soil, under mulch | None; rarely enters homes |
| Bark centipede (Scolopendra subspinipes) | Not native to BC | 21 pairs, robust | Not present in Metro Vancouver | N/A in BC |
Why house centipedes are in your BC basement
House centipedes are predators. Their indoor presence directly indicates prey: silverfish, small cockroaches, ants, carpet beetle larvae, small flies, and other arthropods. They prefer damp, dark spaces — BC basements and crawlspaces are textbook habitat because they combine the humidity centipedes need to breathe through their cuticle with the prey populations that sustain them. A single house centipede can eat multiple silverfish per night. They're fast (up to 0.4 m/sec) and ambush prey in dark corners. They don't aggregate in numbers unless prey is abundant — if you're seeing 5–10 centipedes per week in your basement, you have a significant prey population supporting them. The centipedes are symptomatic, not causal.
The diagnostic value: what your centipede count means
- 1–2 house centipedes seen per month: normal for any BC basement. Baseline predator presence with low prey density. No intervention needed.
- 3–5 per week: elevated prey population — likely silverfish or small flies. Investigate moisture conditions. No direct centipede treatment needed; address the prey.
- Daily sightings across multiple rooms: significant prey infestation. This level of centipede activity usually means a substantial silverfish or cockroach population in wall voids or crawlspace. Comprehensive inspection warranted.
- Centipedes in upper floors (kitchen, bedrooms): unusual and indicates either heavy population pressure from below or an overlooked harborage zone (under appliances, in bathroom wall voids).
How to
Centipede removal protocol — when quality of life demands it
If you need to reduce centipede presence despite their beneficial nature, this sequence works by removing the conditions that support them rather than by direct treatment.
- 1Identify and treat the prey populationInspect for silverfish (check under baseboards, behind electrical outlets, in basement cardboard storage). Inspect for cockroach signs (droppings, egg cases, musty odour near appliances). Inspect for small fly breeding sources (drain buildup, overwatered houseplants, fruit bowl). Treat the prey — the centipedes will follow.
- 2Reduce basement humidityHouse centipedes need ambient moisture. A dehumidifier reducing the basement from 70%+ to below 55% RH makes the habitat less suitable. This also addresses the moisture that supports their silverfish prey — a compound benefit.
- 3Seal entry points from crawlspace and exteriorCentipedes enter basements through utility penetrations, under door gaps, and through crawlspace access points. Seal these with mesh and foam. Pay particular attention to crawlspace-to-basement transitions.
- 4Apply residual treatment at perimeter — last resort onlyIf population reduction is urgent (phobia, confirmed bites), apply a pyrethroid residual treatment along the basement floor-wall junction and at crawlspace entry points. This provides 30–60 days of knockdown. Without addressing the moisture and prey, populations rebound.
Frequently asked questions
Do house centipedes bite?+
Rarely. They can bite if handled or cornered but bites are uncommon in normal household encounters. Bites produce localized pain and redness — comparable to a mild bee sting at most. Not medically significant for the vast majority of people. Allergic reactions are rare but possible.
Will they go away in winter?+
Indoor populations don't experience seasonal reduction because BC basements stay relatively warm year-round. They persist as long as prey is present. Seasonal variation in centipede sightings usually reflects prey population cycles, not temperature.
Are the very large centipedes (50+ mm, thread-like) dangerous?+
Those are soil centipedes (Geophilomorpha) — they occasionally enter through foundation gaps but are completely harmless, move slowly, and don't bite people. Their presence indicates foundation soil contact or gaps; worth sealing but not a health concern.
Can I just vacuum them up?+
Yes. For single encounters or occasional sightings, vacuuming is a practical immediate solution. It doesn't address the underlying population or its prey, but for individual control it works fine. Empty the vacuum bag or canister immediately to prevent escape.