Giant House Spider

Reviewed by TJ, ACE Certified Technician · Updated 2026-06-15

Eratigena atrica | Category: Spiders | Large, fast, but harmless

The Giant House Spider is the big brown spider most PNW homeowners see sprinting across the floor in late summer. It is the largest spider people commonly encounter indoors here, with a leg span that can reach four inches. Despite the size and speed, it is not medically significant. It is also the species most commonly confused with the Hobo Spider, since they are close relatives in the same genus. Here is how to identify it and why our default recommendation is usually to leave them alone if they are not in a problem location.

Quick ID Card
Size	Leg span up to 4 inches
Color	Mottled brown with banded legs
Top ID Marker	Very large size, funnel web in corners
Habitat	Basements, crawl spaces, corners (floor to ceiling), garages
Web	Flat funnel-shaped, often quite large
Bite Risk	Not medically significant
Plan Coverage	✓ Covered under All Seasons Pest Plan

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Quick Answer: The Giant House Spider (Eratigena atrica) is the large fast-moving brown spider most PNW homeowners encounter indoors, particularly in late summer when males wander looking for mates. It builds flat funnel-shaped webs in corners of basements, crawl spaces, and garages, and can reach a four-inch leg span. It is closely related to the Hobo Spider and nearly identical to it without magnification. Neither spider is medically significant, both are considered nuisance pests. Giant House Spiders are actually somewhat beneficial, they prey on other spiders (including Hobos) and other household insects. Startling to see, but harmless.

Key facts at a glance: Leg span up to 4 in · Mottled brown · Fast · Builds funnel webs · Very common indoors · Not medically significant · Beneficial predator · Plan coverage: Yes.

Actually helpful: Giant House Spiders eat other spiders (including Hobo Spiders) and household insects. In basements, garages, and unfinished storage areas, they are effectively free pest control. If one is not in a problem location, leaving it alone is a reasonable choice.

What You Need To Know About Giant House Spiders

Our ACE Certified Technician TJ breaks down giant house spiders and hobo spiders, and why neither one is dangerous.

Frequently Asked Questions

Are Giant House Spiders dangerous?

No. Giant House Spiders are not medically significant. They can bite defensively if trapped against skin, but bites are extremely rare and cause at most brief local irritation similar to a mosquito bite. Despite the alarming size and speed, they pose no real threat.

How do I tell a Giant House Spider from a Hobo Spider?

Without magnification, you often cannot. Both are brown funnel-web builders in genus Eratigena. Giant House Spiders tend to be larger and more comfortable climbing walls. Hobos usually stay at ground level. Positive ID requires microscope work.

Why do I see them in fall?

Mature males wander in late summer and fall looking for females. The dramatic sprints across floors are almost always males on their mating quests.

Are Giant House Spiders beneficial?

In a sense, yes. They prey on other spiders including Hobo Spiders and they consume household insects. In utility areas they function as free pest control.

How long do Giant House Spiders live?

Females can live 2 to 6 years. The big spider in your basement corner may have been there for years.

Does the All Seasons Plan cover them?

Yes. Web sweeping, exterior treatment, and interior spider control are all covered.

Signs You Have Giant House Spiders

Giant House Spiders make themselves known through size, speed, and the trailheads of their funnel webs:

1. Very large brown spider on the wall

A brown spider with a leg span the size of a coaster is almost always a Giant House Spider. That size is the giveaway – nothing else common indoors gets that big.

2. Funnel webs in corners

A flat sheet with a tunnel retreat in the corner of a basement or crawl space is signature Giant House Spider. Their webs can be substantially larger than Hobo webs.

3. Fast sprints across the floor

Giant House Spiders can move up to 2 feet per second in short bursts. If a brown spider crossed your floor at alarming speed, it was probably one of these.

4. Male wanderers in late summer

Late-summer and fall bring mating season. Homeowners often notice males suddenly showing up in bathtubs, on ceilings, and in unexpected spots as they search for females.

5. Fewer Hobo Spiders than expected

Giant House Spiders eat Hobos. Homes with strong Giant House Spider populations often have surprisingly few Hobos.

6. Egg sacs and molted skins

Silky egg sacs attached to walls or the underside of shelves, plus cast skins from molts, indicate an active female with a long-term residence.

Behavior, Biology & Lifecycle

Introduced from Europe

Like the Hobo Spider, the Giant House Spider was introduced to the PNW from Europe. It has thrived here for over a century and is now one of the region\’s most abundant indoor spiders.

Long-lived by spider standards

Females can live 2 to 6 years, unusually long for a spider. This means a single female can occupy a corner of your home for a very long time. Males live shorter lives and die shortly after mating.

Genuinely fast

Giant House Spiders can sprint up to 2 feet per second in short bursts, one of the fastest speeds recorded for a spider. This is why they seem to disappear before you can react.

Habitat: corners, high and low

Unlike the ground-hugging Hobo, Giant House Spiders comfortably climb walls and build webs in upper corners of basements, garages, and crawl spaces. They are equally at home floor to ceiling.

Predators of other spiders

Giant House Spiders will catch and eat Hobo Spiders and other spiders that wander into their webs. In areas with strong Giant House Spider populations, Hobos are often notably absent.

Reproduction

Females produce multiple egg sacs during their long lives, each containing dozens of eggs. Development from egg to adult takes 1 to 2 years.

DIY Homeowner Steps

Sweep webs regularly
Funnel webs get rebuilt fast if the spider is still there. Sweeping every week or two along basement corners and crawl space edges is very effective for keeping populations down.
Reduce ground-level clutter
Bag stored items in sealed plastic, elevate boxes off the floor in basements and crawl spaces. Giant House Spiders hide in ground clutter and cardboard.
Seal entry gaps at foundation level
Weather stripping on doors, screens on crawl space vents, caulk around utility penetrations. Giant House Spiders enter through the same low gaps mice and ants do.
Shake out shoes and gloves stored in garage
If you have not touched something in weeks, a Giant House Spider may have moved in. The rare bite happens when a spider is trapped against skin, usually when someone puts on a stored item.
Vacuum sightings, then dispose
A shop vac with a long hose is the safest removal method. Empty the vac outside immediately after. Do not attempt to handle a Giant House Spider by hand.