How Long Can a House Spider Live Indoors?

Most house spiders live between one and two years indoors, though some species regularly reach three years or more, and a few can survive for the better part of a decade under favorable conditions. The answer depends heavily on which spider has moved in, whether it is male or female, and how stable your home’s temperature and humidity remain. Indoor life, as it turns out, is a remarkably good deal for a spider, and the factors that shorten or extend their stay are worth understanding if you share a home with them.

Which Spiders Are Actually Living in Your House

When people say “house spider,” they usually mean whichever spider they spotted near the bathtub or in the corner of the ceiling. But a handful of species are genuinely adapted to indoor life, and their lifespans vary considerably. The common house spider (Parasteatoda tepidariorum, sometimes called the American house spider) is the one most people encounter. It builds messy cobwebs in corners and window frames and typically lives one to two years. Cellar spiders, the long-legged, delicate spiders that hang upside down in basements and garages, can live two to three years. Giant house spiders (Eratigena atrica), common in the U.K. and the Pacific Northwest, have been recorded living up to three years indoors. And then there are the outliers: some tarantula-like species kept in captivity have lived well over a decade, and even certain cobweb spiders in undisturbed indoor environments can persist for five to seven years.

An important distinction is that many of these spiders are not outdoor spiders that wandered in. Species like Parasteatoda tepidariorum have been living in human structures for so long that they are poorly suited to outdoor survival in many climates. Putting them outside is not “returning them to nature” so much as evicting them from the only habitat they know.

Why Indoor Living Extends a Spider’s Life

The single biggest reason house spiders outlast their outdoor cousins is the removal of the two things that kill most spiders: temperature extremes and predation. Outdoors, a spider faces birds, wasps, lizards, and other spiders, along with freezing winters and scorching summers. Indoors, a heated and cooled building provides a year-round temperature window that sits comfortably within a spider’s tolerable range, and the predator list shrinks to essentially one: you.

Temperature matters more than most people realize. Research on false widow spiders (Steatoda grossa), a species increasingly common in homes across Europe and North America, found that individuals reared at lower temperatures grew more slowly but ultimately reached a larger adult body size. Males, which develop faster than females, were the only ones to reach adulthood in the study’s higher-temperature treatments, illustrating how even moderate heat stress can reshape development and, by extension, lifespan.

The stable humidity inside a home also plays a role. A study on wolf spiders found that individuals survived significantly longer when humidity stayed at or above 50 percent relative humidity. Females showed better dehydration resistance and tolerance overall, with lower body-loss rates and a lower critical mass threshold before dying, suggesting they are physiologically better at conserving water.

Most indoor environments in climate-controlled homes hover between 30 and 60 percent relative humidity, which is within or near that survival-friendly range. Bathrooms, basements, and laundry rooms tend to sit at the higher end, which is one reason you often find spiders in those spots.

How Long Spiders Can Go Without Eating

One of the most common questions people have about indoor spiders is how they survive in a house that seems to have no insects for them to eat. The answer is that spiders are extraordinarily efficient at stretching a meal. Many house spiders can go weeks or even months between feedings, and the mechanism behind this is not simply toughing it out. Spiders actively downregulate their metabolism when food becomes scarce.

Research on wolf spiders showed that respiratory rates increased slightly during the first two days of starvation but then dropped sharply from the third to the twelfth day. After the twelfth day, metabolic rates stabilized at roughly half the pre-starvation level in males and about 63 percent in females. Body weight decreased slowly and linearly during this period, but the rate of loss was small. The researchers concluded that this metabolic suppression was not a sign of exhaustion or decline. When the same spiders were given food again after the starvation period, their respiratory rates and body weight recovered to near-normal within five days. The spiders were not dying slowly; they had shifted into a kind of low-power mode.

The study also found evidence that starved spiders shifted to burning a higher proportion of fat as their energy source compared to well-fed spiders, which is an efficient survival strategy. This metabolic flexibility is part of why a spider can sit in your garage for what feels like an impossibly long time without any visible prey and still be perfectly alive.

For the common house spider, which sits in a web and waits rather than actively hunting, the energy expenditure between meals is already low. A cobweb spider in a quiet corner of a basement can survive on a strikingly small number of prey items per month. Even in homes that seem insect-free to human eyes, there is usually enough microscopic life — fungus gnats, springtails, booklice, mites — to sustain a small spider population.

Do Males and Females Live Equally Long

In almost every spider species studied, females outlive males, often by a wide margin. The pattern holds indoors too. Male house spiders tend to have shorter lifespans for overlapping reasons: they mature faster, they are smaller, and once they reach adulthood, their primary biological drive switches from feeding and growing to finding a mate. In many species, adult males largely stop eating, leave their webs, and begin wandering. That wandering phase is when you are most likely to see a spider crossing your floor, and it is also the most dangerous period of a male spider’s life, even indoors. Dehydration risk rises, the chance of being spotted and killed by a human increases, and the male’s own energy reserves are running down.

The dehydration study mentioned earlier quantified part of this gap. Female wolf spiders had better survivorship overall, lost body water at lower rates, and could tolerate a lower critical body mass before dying. Males, despite starting with a higher percentage of body water relative to their weight, lost that water faster and died sooner under the same conditions.

For common house spiders specifically, females typically live around a year to two years, while males may live only a few months to about a year. The female you see sitting patiently in a web in September may still be alive next spring. The male scurrying across your living room at night is likely on borrowed time regardless of whether you intervene.

How Indoor Lighting Can Shorten a Spider’s Life

Here is a factor most people never consider: the light in your home can meaningfully alter a spider’s biology. Many house-dwelling spiders are nocturnal or crepuscular, and they evolved under conditions where nighttime meant actual darkness. Modern indoor environments, with lights left on in the evening and ambient glow from electronics, create a very different light regime.

A study on nocturnal orb-web spiders found that exposure to artificial light at night (even at levels as low as 20 lux, which is roughly equivalent to a dim hallway or a nightlight) accelerated juvenile development. Spiders under these conditions matured earlier, went through fewer molts, and ended up smaller as adults. Daily juvenile mortality increased under the 20 lux treatment, though because the spiders matured faster, roughly the same total number reached adulthood as in the dark-reared group. The reproductive cost was substantial: females reared under artificial light produced considerably fewer eggs, largely because of their reduced adult body size.

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What this means for house spiders is that constant indoor lighting may push them toward a “live fast, die young” trajectory. They mature sooner and at a smaller size, which in spiders generally correlates with a shorter adult lifespan. If you have spiders in rooms that are dark most of the time, like a basement or storage closet, those spiders may actually grow larger and live longer than ones in well-lit areas of the same house. The research is not yet extensive enough to put exact numbers on the indoor lifespan difference, but the direction of the effect is clear.

What an Aging Indoor Spider Looks Like

Spiders do not gray at the temples, but they do show signs of decline that are visible if you know where to look. The most studied indicator is web quality. Research on orb-web spiders found that as spiders approached their natural death, the distance they traveled during web construction decreased, the total time they spent moving dropped, and the time spent building the capture spiral shortened. These changes became apparent in the final weeks of life. Interestingly, the speed at which spiders moved did not change as death approached; they simply moved less and built less.

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For house spiders, the practical sign is a web that looks increasingly ragged and patchy. A healthy house spider refreshes or rebuilds its web frequently, adding silk and repairing damage. An aging spider may stop maintaining its web altogether, sitting motionless in the remains. You might also notice the spider looking visibly thinner or smaller, though distinguishing a starving spider from an old spider by eye alone is difficult. In many cases, you will simply find the spider dead in or near its web one day, legs curled inward in the characteristic death posture that results from loss of hydraulic pressure in the legs.

Common Things That Kill Indoor Spiders Early

While a house spider in ideal conditions can live out its full natural lifespan, several common household factors cut that short. The most obvious one is direct human intervention: vacuuming, swatting, or crushing. But there are subtler threats as well.

Pesticide exposure: Indoor insecticide sprays and residual treatments kill spiders directly or eliminate their prey base. Even low-level exposure to common household insecticides can impair web-building and reduce prey capture, effectively starving the spider even if the chemical does not kill it outright.
Low humidity: Forced-air heating in winter can drive indoor humidity below 20 percent in some homes, well below the threshold where spiders start losing body water dangerously fast. Spiders in heated rooms without any humidity source are at particular risk during cold, dry months.
Other spiders: Interspecific predation (one spider species eating another) is a real and underappreciated source of indoor spider mortality. Cellar spiders are known to prey on larger house spiders. If your home hosts multiple spider species, the population dynamics involve some of them eating the others.
Starvation: While spiders can survive long stretches between meals, a truly insect-free environment will eventually kill them. Very clean, well-sealed modern homes with good pest control may simply not produce enough prey to sustain a spider population indefinitely.

Pets are another factor. Cats in particular will hunt and kill spiders opportunistically, though most cats treat spiders more as toys than food. A spider in a room a cat frequents has a meaningfully shorter life expectancy than one in an undisturbed attic.

Should You Leave Them Alone

This is ultimately a personal comfort question, but the practical case for coexistence is straightforward. A house spider in a corner is quietly consuming small insects and other arthropods that you would prefer not to share your home with. Cobweb spiders catch flies, mosquitoes, and moths. Cellar spiders, as noted, even eat other spiders, including species people find less welcome. The amount of pest control provided by a small indoor spider population is modest but real, and it costs you nothing.

If you cannot tolerate the sight of them, relocating a spider to another room (or into a garage or shed) is a more humane and practical option than killing it, with the caveat that true house spiders released outdoors in a cold climate will likely not survive. For species that are genuinely indoor-adapted, the choice is between tolerating them where they are or accepting that removing them from the house is essentially a death sentence.

When a Spider in Your Home Is Not a House Spider

Not every spider you find indoors is a permanent resident. Many spiders that end up inside are outdoor species that wandered in through a gap, an open door, or on a piece of firewood. These spiders are often disoriented, do not build webs in the same spots a house spider would, and are unlikely to survive long indoors. Ground spiders, jumping spiders, and various hunting spiders may show up on walls or floors, especially in autumn as outdoor temperatures drop. These visitors rarely live more than a few weeks inside a house, partly because the indoor environment does not suit their hunting style and partly because they may not find food.

The distinction matters for lifespan expectations. If you see a large, fast-moving spider sprinting across your floor, it is probably a wanderer or a male looking for a mate, not a settled resident with a long future in your home. The spiders with the longest indoor lifespans are the quiet, web-building females tucked into corners you rarely disturb. Those are the ones that can genuinely share your home for years at a stretch, rebuilding their webs at night while you sleep, and growing slightly smaller and slower as they age until they eventually stop moving for good.

1
PubMed Central. Exposure to high temperatures is fatal for eggs and suppresses growth in a false widow spider, Steatoda grossa
2
Canadian Journal of Zoology. Dehydration resistance and tolerance in the brush-legged wolf spider (Schizocosa ocreata): a comparison of survivorship, critical body water content, and water-loss rates between sexes
3
Population Ecology. Decrease in respiratory rate in a wolf spider, Pardosa astrigera (L. Koch), under starvation
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PubMed Central. Artificial light at night alters life history in a nocturnal orb-web spider
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PubMed Central. Time till death affects spider mobility and web-building behavior during web construction in an orb-web spider