The grey house spider (plus 8 other indoor species)

Updated on March 15th, 2025

Why do spiders evoke such fear in us? Is it their silent movements, their eight-legged stance or the unexpected places they appear? Despite their unsettling presence, most household spiders are harmless and even beneficial.

Among the many house-dwelling spiders, the grey house spider (Badumna longinqua) is a secretive yet harmless species commonly found in California and Florida. Though rarely seen, it prefers quiet, sheltered spaces and contributes to natural pest control by preying on insects.

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What are spiders? Is a spider an insect?

Spiders have multiple eyes (in pairs) and eight legs—not six. They also lack antennae, making them technically not insects. Boo! Did that surprise you as much as stumbling upon a spider in a dimly lit corner? 

Here’s what’s unique about spiders:

•  Spiders breathe with a dual system | Spiders have a unique respiratory system—a combination of lungs and tracheae—that sets them apart in the animal kingdom. Picture this: While we rely solely on our lungs for breathing, spiders (Araneae) harness their book lungs and a network of tracheae. These tracheae, tiny tubes funneling air directly through openings known as spiracles, allow spiders to breathe in a way no other creatures do.
• Spiders can ingest silk | The orb spider recycles the amino acids that make up the silk proteins of its web by simultaneously ingesting the silk and dismantling their damaged web every day.
• Not all spiders make webs | Around 50% of spiders build webs to catch their prey. While only half of spider species weave webs for hunting, their designs vary widely—from the delicate orb webs to the intricate funnel webs that house multiple generations.
• Spider’s silk is a lifeline | It can be used as a safety line when escaping predators, to hold an underwater air supply—for water spiders—and to disperse spiderlings to wherever their new homes will be.

How many spiders are in your home (and on earth)?

Spiders are some of the most fascinating—and sometimes unsettling—creatures that share our homes. You might be wondering about the number of spiders in your living room. Well, the answer isn't straightforward, but here are two mind-boggling facts to ponder:

For every one of us, there's a bustling community of about 3 million spiders.

Studies by Martin Nyffeler and Klaus Birkhofer show that spiders munch on 400-800 million tons of prey each year. That's a staggering amount, easily enough to include every last one of us, along with our friends and families. So next time you spot a spider in the corner, remember – it's part of a vast, global network of nature's most efficient pest controllers.

What is the grey house spider?

The grey house spider (Badumna longinqua) is a reclusive species that thrives in undisturbed areas like eaves, window frames and garden sheds. Unlike delicate cobweb spinners, this spider constructs dense, messy silk retreats that provide both shelter and protection. Though often unnoticed, it plays a valuable role in reducing household pests like flies and mosquitoes.

Fun fact: The grey house spider’s silk is thicker and more irregular than other common house spiders, offering a sturdier hideout against predators.

Common house spiders found indoors

Most common house spiders are seen in autumn when males leave their webs to find females. The term "house spider" refers to multiple species that live near or inside human dwellings. Here are the nine most common spiders found indoors in North America:

Spider name	Size & color	Habitat	Notable features
Grey house spider	~1.5 in., gray	Secretive, found in California and Florida	Secretive, non-aggressive; builds silk retreats
Brown house spider (false widow)	~1 in., dark brown	Secluded indoor areas	Resembles a smaller, less dangerous black widow
American house spider	0.5–1 in., brown to gray	Corners, windows	Builds messy cobwebs
Cellar spider	2–2.5 in., pale	Basements, cellars	Shaky movement when disturbed
Domestic house spider (barn funnel weaver)	1.5–2 in., brown	Outdoor structures, home crevices	Builds funnel-shaped webs; swift runner
Giant house spider	3–4 in., brown	Dark, moist areas	Very large; builds large sheet webs with funnel retreats
Hobo spider	1.5–2 in., brown with distinct abdominal pattern	Ground-level funnel webs	Commonly misunderstood as aggressive
Southern house spider	Males: 1–1.5 in., light brown Females: 1.5–2 in., dark brown	Windows, attics, under eaves	Sexual dimorphism; females rarely leave webs
Yellow sac spider	~1 in., pale yellow	Walls, ceilings, inside homes	Long, slender legs; nocturnal

Now that we’ve covered a quick overview, let’s take a closer look at the unique characteristics of these common house spiders and what makes them stand out.

• Grey house spider (Badumna longinqua) | A non-aggressive, nocturnal species that avoids open spaces. It builds dense silk retreats in undisturbed locations like window frames, garden sheds and eaves.
•  Brown house spider or false widow (Steatoda grossa) | Sometimes confused with the black widow, this harmless look-alike is non-aggressive, preying on other pests, including real black widows. It spins messy, irregular webs in quiet corners
• American house spider (Parasteatoda tepidariorum) | A true cobweb master, known for its adaptability to human homes. It thrives in dark corners.
• Cellar spider (Pholcus phalangioides) | This species is famous for its shaky, vibrating defense mechanism, which confuses predators. Despite its delicate build, it’s an effective predator of other spiders.
• Domestic house spider or barn funnel weaver (Tegenaria domestica) | This speedy hunter builds funnel-shaped webs and dashes out to ambush prey. Though often feared, it avoids human interaction and prefers dark, undisturbed areas.

• Giant house spider (Eratigena atrica) | One of the most enormous house spiders, but far less aggressive than its intimidating size suggests. Often mistaken for the hobo spider, it prefers to flee rather than bite.
• Hobo spider (Eratigena agrestis) | Once wrongly believed to be a venomous threat, recent studies suggest its bite is medically insignificant. It constructs ground-level funnel webs and is more reclusive than aggressive.
• Southern house spider (Kukulcania hibernalis) | One of the most sexually dimorphic house spiders—males roam widely, often startling homeowners, while females remain hidden in their dense, silken retreats.
• Yellow sac spider (Chiracanthium inclusum) | A nocturnal wanderer, often mistaken for more dangerous species due to its bite, which can cause mild irritation. It actively hunts prey and prefers to rest in silk sacs during the day.

How to identify which spiders are in your home

Identifying common house spiders can feel overwhelming, but by focusing on key characteristics, you can narrow it down. Follow these four simple steps to determine what kind of spider you’re dealing with.

1. Check the web type

Does your spider make a messy cobweb, a funnel web or no web at all?

• Messy cobweb → Likely an American house spider (common in corners and windows)
• Funnel web → Could be a barn funnel weaver or hobo spider (often near ground level or in basements)
• No web → Likely a yellow sac spider (often seen on ceilings or walls)

2. Look at the leg-to-body proportion

Are the legs noticeably long compared to the body?

• Yes, very long legs → Likely a cellar spider (also called a "daddy longlegs")
• No, legs are proportionate → Could be a domestic house spider (stockier, thicker legs)

3. Examine the coloration and markings

Does the spider have a violin shape or an hourglass marking?

• Violin-shaped marking on the back → Brown recluse (be cautious—this species has venom that can cause skin irritation)
• Red hourglass on underside → Black widow (another venomous species to watch out for!)
• No distinct markings → Likely an American house spider or hobo spider

4. Observe where you found it

Was it in a basement, on a ceiling or near a window?

• Basement or dark, damp area → Cellar spider
• Ceiling or upper corners of rooms → Yellow sac spider or American house spider
• Near a window, doorway or secluded crevice → Southern house spider or grey house spider (both prefer undisturbed areas)

Dangerous spiders to watch for

In spider identification, ensure you do not have a brown recluse, black widow or a hobo spider in your home. These are the three most venomous spiders in North America. They have fangs and venom that can penetrate (aka bite) human skin.

• Brown recluse spiders (Loxosceles reclusa) | They have a telltale violin shape on their backs, a medium-brown body, brown legs and six eyes. They prefer warm, dry places, like a shed or woodpile.
• Black widow spiders (Latrodectus) | They are a striking shiny black color with a bright red hourglass shape on their abdomens. They have long legs that taper into points and typically dwell in woodpiles and under leaves.
• Hobo spiders (Eratigena agrestis) | They are brown with chevron-shaped yellow markings and build webs in cracks, corners and holes. They are commonly found in woodpiles and other sheltered locations.

How long do spiders live?

A spider’s life span varies greatly, depending on its species and whether we’re talking about a female or male — as female spiders tend to live longer than male spiders. This could be because of genetic strength, as female spiders are responsible for laying eggs and taking care of their young. It could also be because some species of female spiders actually kill or consume their mate after they have finished mating. (In some cases, the female will even catch the male when he attempts to escape.) Many male spiders reach maturity within two years and die after mating.

Here are some spider lifespan examples

• The common house spider (Parasteatoda tepidariorum) | Lives for about 1 year.
• The grey house spider (Badumna longinqua) | Typically lives for about a year, though some may survive longer in undisturbed conditions.
• The barn funnel weaver (Tegenaria domestic) | Has a life expectancy of up to 7 years.
• Black widow spiders (Latrodectus) | Can live for up to 3 years.
• Tarantulas (Theraphosidae) | Can live anywhere from 10-30 years.
• Male wolf spiders (Lycosidae) | Often live no more than one year; however, their female counterparts can live several years.
• The average trapdoor spider (Ctenizidae) | Lives 5-20 years, though the world’s oldest spider was a trapdoor spider—and lived to be 43.

Fun fact: Male spiders of the species Thanatus fabricii (which doesn't have a common name) bite and tie up their female partners with silk before mating to avoid being eaten.

Is it good to have some spiders in my house?

House-dwelling spiders, including the grey house spider, provide free year-round pest control and take care of pests such as mosquitoes, flies, fleas and even cockroaches. I’m not suggesting you allow them to freely take up residence in your home, but I am saying there is wisdom in allowing the occasional spider—neither dangerous or aggressive—to live in your basement or attic, (where you or any house guests are least likely to have 1:1s with them).

Fun fact: Spiders are their own fiercest competitors, often engaging in deadly battles with kin for dominance, leading to dramatic fluctuations in their numbers – one day you might find a bustling community and the next, only the fattest victors remain.

3 reasons to keep the occasional spider

• They feed on common indoor pests. One spider can eat 2,000 insects in one year.
• They help curtail disease by preying on insects—such as mosquitoes and flies—that can transmit diseases to humans and our beloved pets.
• They get rid of one another. The most common long-legged cellar spiders are known to kill black widow spiders.

Fun fact: The huntsman spider (which is different from the giant huntsman spider), American house spider and jumping spider have all been known to eat cockroaches.

How to get rid of spiders in the home

Some folks are not only scared of spiders, but consider the spider itself as scary. We all try to avoid experiences that make us feel uncomfortable. For those looking to eliminate spiders, a fine insect powder applied with a precision duster can be effective.

Dust to Dust Plant-Powered Insect Powder employs silica to break down the delicate wax layer that covers arachnids (and insects) exoskeletons. This wax coating is critical for these bugs as it helps prevent the loss of water from their bodies through the exoskeleton. The breakdown of this layer leads to the spider's death—through dehydration.

Directions: Fill The Insect Buster Bulb Duster three-fourths full with Dust to Dust. Tap the sides to settle the powder, then lightly squeeze to apply it in areas where spiders are active or may enter, such as corners, crevices and windowsills. For best results, ensure the areas are dry and lightly coat surfaces where spiders are likely to crawl, ensuring they come into direct contact with the powder.