The giant house spider is one of the most common large spiders in Washington State, and if you’ve spotted a fast-moving, long-legged spider darting across your floor or lurking in a corner, this is likely what you’re looking at. With a leg span reaching up to 4 inches in large adults, it’s an intimidating find, but it poses no real danger to people.
What Giant House Spiders Look Like
These spiders range from brown to grayish-brown, with bodies typically between half an inch and one inch long (not counting the legs). The legs are what get people’s attention. Fully spread, a large adult can span about 4 inches, which is roughly the width of your palm. Both the body and legs are somewhat hairy and have a matte finish rather than a glossy or shiny look.
One tricky thing about identifying them: they’re extremely variable. Color ranges from light tan to dark brown, and markings on the body and legs can be bold and distinct on one spider and nearly invisible on another. Washington State University notes that color, size, and markings alone aren’t reliable enough to confirm identification. If you need a definitive ID, the most accurate method involves examining the spider’s reproductive structures under magnification, which is really only practical for entomologists.
Giant House Spider vs. Hobo Spider
This is the comparison most Washington residents care about. The hobo spider has a reputation (largely undeserved, based on more recent research) as a medically significant spider, and the two species look strikingly similar. Both are brown, hairy, and build funnel-shaped webs. Both show up in the same places: basements, garages, window wells, and ground-level rooms.
The giant house spider is generally larger, but smaller individuals overlap in size with hobo spiders, so size alone won’t settle it. The same goes for color and patterning. Even experienced pest control professionals can confuse the two without close examination. The practical takeaway: if you’re seeing a brown, funnel-web-building spider in your Washington home, it could be either species, but the giant house spider is more common in most urban and suburban areas west of the Cascades. And neither species is considered dangerous. The CDC does not list the hobo spider as a venomous spider of medical concern, and giant house spiders are similarly harmless.
Why They Show Up in Your Home
Giant house spiders are most visible in late summer and early fall, roughly August through October. This is mating season. The large spiders you’re seeing sprinting across the living room floor are almost always males searching for females. They’ve likely been living in your home or its immediate surroundings for a while, but males become conspicuous wanderers when they’re looking for a mate. They don’t come inside from the cold. Most were already indoors or in sheltered spots near the foundation.
Their preferred habitats include basements, crawl spaces, garages, closets, and any undisturbed corner where they can build a flat, funnel-shaped web. Outdoors, they favor spaces under rocks, woodpiles, and dense vegetation near the ground. Homes with cluttered storage areas, gaps around doors or windows, or vegetation growing against the exterior walls tend to have more of them.
Are They Dangerous?
Giant house spiders can bite if handled or trapped against skin, but bites are rare and comparable to a mild bee sting. They are not aggressive toward people. Their instinct when disturbed is to run, and they’re remarkably fast for their size. There are no verified cases of medically significant reactions to giant house spider bites. If you’re bitten by any spider and develop unusual swelling, spreading redness, or systemic symptoms like fever, that warrants medical attention regardless of species.
Keeping Them Out of Your Home
The most effective long-term strategy is making your home less inviting. Regular, thorough cleaning does the most work. A vacuum cleaner removes spiders, their webs, and egg sacs in one pass. Focus on corners, along baseboards, behind furniture, and in storage areas that don’t get much traffic. Reducing clutter in basements, garages, and closets eliminates the sheltered, undisturbed spaces these spiders prefer.
Sealing entry points helps prevent new spiders from moving in. Install tight-fitting window screens and door sweeps. Check for gaps around pipes, vents, and where utility lines enter the home. Outside, move firewood, stacked materials, and debris away from the foundation. Trim back shrubs, vines, and tree limbs that touch the house, since these create both shelter and a bridge for spiders to reach the structure.
Sticky traps placed in corners and flush against walls can catch wandering males during mating season. Several traps spread across a room work better than one or two. If you’d rather relocate a spider than kill it, the classic glass-and-cardboard method works well: place a glass over the spider, slide a stiff card underneath, and carry it outside. For persistent or heavy infestations, insecticide sprays labeled for spiders and crawling insects can be applied along baseboards and entry points, though cleaning and exclusion will always do more in the long run than spraying alone.
Why Washington Has So Many
Giant house spiders are native to Europe and were introduced to the Pacific Northwest, where the mild, damp climate suits them perfectly. Western Washington, with its moderate temperatures and high humidity, is ideal habitat. They’re well established from Seattle and Tacoma down through Olympia and across to Vancouver and Portland. East of the Cascades, where conditions are drier, they’re less common but still present in irrigated urban areas. The species has been in the region for decades and is thoroughly naturalized, so they’re not going anywhere. Learning to coexist with them, or at least knowing how to manage them, is part of living in the Pacific Northwest.