Identification
Parasteatoda tepidariorum — formerly classified as Achaearanea tepidariorum in older BC literature — is the small tangled-web spider most British Columbians see indoors. Females are 5 to 8mm in body length, males 3 to 5mm; leg span roughly doubles body length. Colour varies from yellow-brown to grey-brown, with indistinct chevron or spot patterns on the abdomen. The body is clearly bulbous — a typical 'comb-footed' spider shape. Webs are distinctive: irregular three-dimensional tangles of fine silk with a narrower dense section at the retreat, built in corners, under eaves, behind furniture, and anywhere relatively undisturbed. The species is sometimes confused with the much smaller and harmless false black widow (Steatoda species), which look similar in silhouette.
Habitat in BC
Common house spiders live in the sheltered, undisturbed corners of Metro Vancouver homes and outbuildings. Basements, garages, crawlspaces, detached sheds, the underside of decks, behind shrubs against foundations, in window-well corners, and inside rarely-used storage spaces are the classic sites. They are synanthropic — essentially requiring human structures for habitat in BC's climate — and occur in essentially every residential neighbourhood in Metro Vancouver. Rural and urban prevalence is similar. Population density tends to be higher in older homes with more undisturbed interior corners and in homes with active garden-insect populations providing food.
Signs you have common house spider
- Tangled three-dimensional cobwebs in basement corners, garage ceilings, or behind stored items.
- Small pea-sized brown egg sacs suspended inside or near the web.
- Individual small brown spiders retreating to the tight end of the web when approached.
- Desiccated insect prey (fly wings, beetle shells) visible in the web.
- Multiple webs in the same undisturbed area — Parasteatoda tolerates high density when food is abundant.
Risk & damage
Essentially zero meaningful risk. Parasteatoda tepidariorum is medically insignificant — bites are extremely rare, non-aggressive, and when they do occur produce at most a minor local reaction similar to a mosquito bite. They are not the black widow and are not medically related to dangerous spiders. On the contrary, the species is genuinely beneficial: a single house spider consumes 200 to 400 insects per year, including flies, mosquitoes, moths, and small beetles that are themselves nuisance or vector species. From a public-health perspective, a home with an active house-spider population is a home with meaningful biological pest control. The only legitimate reasons to reduce house-spider density are aesthetic (visible webs) and mild arachnophobia.
Seasonality in Metro Vancouver
Common house spiders are active year-round indoors with essentially no seasonal variation in heated BC homes. Outdoor populations in garages, sheds, and under decks peak in activity late summer and early fall (August through October) when prey is abundant and the females produce egg sacs. Winter populations persist indoors in lower numbers, consolidating around heat sources. Fall is the classic 'spider season' that drives Metro Vancouver homeowner complaints — not because the spiders are new, but because adult males are searching for mates and are more visible during daytime walking across floors and walls.
Treatment approach
Because house spiders are genuinely beneficial and medically insignificant, our default recommendation is not a dedicated spider treatment. For clients with moderate arachnophobia or specific aesthetic concerns, our quarterly plan includes perimeter treatment at common spider-harbourage sites — corners, eaves, window frames, basement edges — using a registered residual pyrethroid, plus physical web removal during each quarterly visit. This reduces visible webs and foraging opportunity without attempting to sterilise the home of spiders (which is both impossible and ecologically counter-productive). For homes with hobo spider or Western black widow concerns, treatment focus shifts — see those species-specific pages. Our quarterly plan pricing ($139/visit) is the most cost-effective approach for managing nuisance-level spider density.
When to call a professional
You don't strictly need to for common house spiders alone — their presence is biologically neutral or mildly beneficial. Call if you have a persistent web problem that physical removal doesn't solve, if you're concerned about distinguishing house spiders from potentially medically significant species (Western black widow, hobo spider), if arachnophobia is meaningfully affecting use of your home, or if you'd like to include spider management in a broader perimeter pest service like our quarterly plan.
Prevention playbook
How to prevent common house spider in Metro Vancouver homes
- 1
Reduce exterior lighting or switch to yellow bulbs
Bright exterior lights attract the flying insects that spiders feed on. Switch to yellow "bug-resistant" LEDs, or use motion-activated lights — fewer insects near entry points means fewer spiders.
- 2
Remove wood, debris, and brush piles
Spider harbourage against a house: firewood piles, leaf accumulations, unused garden tools, stacked containers. Move these 1.5m+ from the building.
- 3
Seal cracks and window frames
Spiders enter through the same gaps everything else does. Seal foundation cracks, window frame gaps, and door thresholds with exterior caulk and door sweeps.
- 4
Vacuum webs + egg sacs in late summer
Peak house-spider season is August-October. Weekly vacuuming of webs + visible egg sacs (spherical, cream-coloured, pea-sized) reduces next-generation emergence.
- 5
Consider living with them elsewhere
House spiders eat bed bugs, cockroach nymphs, silverfish, and fruit flies. In garages, basements, and storage areas they are net-beneficial and do not warrant removal.
The Wild Pest service
See our Common House Spider treatment page
Transparent pricing, 60-day return guarantee, same-day response across Metro Vancouver. Every treatment is documented with photos and service notes.
Frequently asked questions about common house spider
Are common house spiders dangerous?+
No. Parasteatoda tepidariorum is medically insignificant — not venomous to humans in any meaningful way, non-aggressive, and essentially incapable of producing a bite that requires medical attention. They are not black widows, not hobo spiders, not brown recluses (brown recluses do not occur in BC at all). A home with many Parasteatoda webs is a home with a small beneficial predator population, not a home with a dangerous-spider problem.
How can I tell them apart from a black widow?+
Western black widows (Latrodectus hesperus) are distinctly black with a bright red hourglass on the underside of the abdomen. Common house spiders are mottled brown with no red markings, and the body shape is less glossy and more pea-like. Black widows build their webs close to the ground under debris and in dry protected spaces; house spiders build up high in corners. In Metro Vancouver, Parasteatoda is vastly more common than Latrodectus — 99%+ of household spider sightings are house spiders.
Why do I see more spiders in fall?+
Two reasons. First, adult males go wandering in late August through October to find mates, and are more visible during daylight walking across floors, walls, and ceilings. Second, declining outdoor insect populations concentrate spider foraging at web sites, making webs more obviously occupied. The overall indoor population isn't dramatically larger in fall — the spiders are just more visible than they are in summer.
Should I kill them or put them outside?+
Outside works in summer but will likely kill them in winter — Parasteatoda tepidariorum does not thrive outdoors in BC's wet cold months. The most practical answer for most BC homes is to leave low-visibility populations alone (they're providing free insect control) and remove high-visibility webs with a vacuum or broom. Dedicated killing provides no meaningful benefit and reduces natural pest control.
Will a spider treatment also kill useful spiders?+
Yes — perimeter spider treatments are not species-selective. This is one reason we prefer to include spider management inside our broader quarterly plan rather than treat as a standalone service. If you have a specific medically significant species concern (Western black widow, hobo spider), targeted treatment of those areas is reasonable; whole-home spider elimination is neither necessary nor desirable.
Related species