Spiders in the House: Why They Come In and How to Keep Them Out

Finding spiders in your home is one of the most common household pest complaints. While some spiders accidentally wander in, others have adapted to live their entire lives indoors. Understanding why spiders end up in your house is the key to keeping them out.

Why Are There Spiders in Your House?

Following Prey

The most important factor driving spiders indoors is the presence of prey insects. If your home has flies, moths, gnats, mosquitoes, or other small insects, spiders will follow the food supply. Address the insect problem, and the spider problem often resolves itself.

Seeking Shelter

Spiders are drawn to sheltered, undisturbed spaces — which describes many areas of a typical home. Basements, garages, closets, attics, and crawl spaces provide ideal conditions for web building and hunting.

Weather

Extreme weather pushes spiders indoors. Rain floods ground-level hiding spots, and cold winter temperatures drive spiders to seek warmth. Fall is the peak season for indoor spider sightings because male spiders wander in search of mates and cooling temperatures push both spiders and their prey indoors.

They Were Already There

Some spiders you find indoors never actually "entered" — they hatched from egg sacs inside your home. House spiders in particular may spend their entire lives indoors, reproducing through multiple generations.

Common Spiders Found Indoors

• House spiders: Tangled cobwebs in corners. Harmless.
• Cellar spiders: Long-legged, found in damp areas. Harmless.
• Wolf spiders: Large, fast-running, ground-level. Harmless but intimidating.
• Jumping spiders: Small, active on walls and windows. Harmless.
• Brown recluses: In south-central US only, found in undisturbed areas. Medically significant.
• Black widows: In dark, sheltered areas at ground level. Medically significant.

Room-by-Room Guide

Basements

Basements are prime spider habitat due to darkness, humidity, and low foot traffic. Dehumidify, reduce clutter, and seal foundation cracks.

Garages

Garages offer abundant hiding spots among stored items. Store belongings in sealed plastic bins and maintain clean floors.

Bathrooms

Bathrooms attract spiders with moisture. Fix leaks, improve ventilation, and seal plumbing penetrations.

Bedrooms

Spiders near beds are especially unwelcome. Keep beds away from walls, bedding off the floor, and the room clean and clutter-free.

How to Keep Spiders Out

Follow these spider prevention tips:

1. Reduce prey insects: Fix screens, seal food, clean regularly.
2. Seal entry points: Caulk cracks around windows, doors, foundations, and utility penetrations.
3. Reduce clutter: Eliminate hiding spots, especially in storage areas.
4. Manage lighting: Use yellow or sodium vapor exterior bulbs.
5. Remove webs: Regular web removal discourages rebuilding.
6. Use deterrents: Natural repellents like peppermint oil around entry points.
7. Monitor: Place sticky traps to track spider activity.

How Many Spiders Are Normal?

Research suggests the average home contains 20 to 60 spiders at any given time, mostly hidden from view. Most of these are harmless species going about their business in wall voids, behind furniture, and in other out-of-sight locations. If you are seeing spiders occasionally, that is normal. If you are seeing them daily in multiple rooms, or finding egg sacs and fresh webs throughout the home, you may have an infestation worth addressing.

The Catch-and-Release Approach

For individual spiders in living spaces, capture and release is often the best approach:

1. Place a clear glass or cup over the spider.
2. Slide a stiff piece of paper under the cup.
3. Carry the spider outside and release it several feet from the home.
4. Release it near vegetation or ground cover where it can find shelter.

This method is humane, effective for occasional sightings, and avoids the mess of crushing or spraying.

Indoor Spiders That Cannot Survive Outdoors

It is worth noting that some house spiders have adapted so thoroughly to indoor life that releasing them outdoors is effectively a death sentence. These species have lived indoors for generations and lack the ability to survive in outdoor conditions. If this concerns you, simply relocate them to a basement or garage where they can live without bothering you.

For serious spider problems or venomous species, consider professional spider control. For complete information, see our complete guide to spiders.

Expert Insights

In 15 years of IPM practice, I have inspected thousands of homes for spiders. The most important thing I have learned is that some spiders in a house are completely normal and even beneficial. I always tell clients that a spider-free home is neither realistic nor desirable. The goal should be managing populations of unwanted species while tolerating the harmless ones that provide natural pest control. When I correct a misidentification — like the client who was convinced she had brown recluses in Connecticut, well outside their range — the relief is palpable. — Sarah Mitchell, BCE

Sources and References

• National Pest Management Association (NPMA)
• Ohio State University Extension
• University of California Riverside Spider Research
• Burke Museum of Natural History and Culture

Main Causes

Indoor spiders activity reflects two drivers — a hospitable indoor environment and a sufficient supply of insect prey. Spiders enter through gaps under doors, around windows, utility penetrations, and any opening leading to attics, basements, garages, or crawl spaces. Once inside they settle wherever undisturbed corners, low light, and easy prey access converge. Cooler weather pushes outdoor species inside in late summer and fall as they seek mating sites or shelter. The most important upstream driver is the indoor insect population — homes with active fly, gnat, moth, or other pest activity sustain larger spider populations than homes without prey. Cluttered storage areas, accumulated webbing, and outdoor lighting that draws nocturnal insects all amplify the indoor pressure.

How to Identify

Identification matters because risk and control differ significantly by species. Most household spiders — cellar spiders, common house spiders, jumping spiders, wolf spiders — are harmless and beneficial. Two species in North America warrant caution: the black widow with its shiny black abdomen and red hourglass marking, and the brown recluse with its violin-shaped marking and uniform tan-brown coloring without leg banding. Check webs for shape and structure: tangled cobwebs in corners indicate cellar or common house spiders; funnel-shaped webs near ground level indicate funnel-web species; sheet webs across grass are usually grass spiders. Single sightings without webs are usually transient outdoor species and do not indicate an infestation.

Risk and Severity

Most spiders found in and around North American homes pose no medical risk to humans and provide net benefit by reducing other pest populations. Two species warrant medical caution: the black widow, whose venom can produce systemic symptoms including muscle cramping, abdominal pain, and elevated blood pressure; and the brown recluse, whose bite can produce a slowly developing necrotic lesion in a minority of cases. Bites from either species generally respond well to medical care, and fatalities are extremely rare. The far more common spider-related problem is aesthetic — webs, egg sacs, and visible spiders cause distress without medical significance. Risk concentrates in undisturbed storage areas, garages, basements, and outbuildings.

Solutions and Actions

For most spider species the goal is removing webs and reducing prey rather than chemical treatment. Vacuum or sweep down all visible webs weekly, including egg sacs, in garages, basements, attics, eaves, and exterior corners. Reduce indoor insect populations by maintaining screens, sealing entry points, and addressing any active pest issue — fewer insects means fewer spiders. Apply a residual insecticide barrier to the foundation perimeter, around windows and doors, and in eaves to deter newly arriving spiders. For confirmed black widow or brown recluse populations in storage areas, use professional pest control, wear long sleeves and gloves when handling stored items, and shake out shoes and clothing left in garages or basements. Single sightings indoors without webs are usually transient and need no chemical response.

Prevention

Prevention works by reducing indoor prey and limiting entry. Vacuum corners, ceiling angles, undisturbed storage, and basement and garage areas weekly to remove webs, egg sacs, and the dust that supports prey populations. Seal gaps around doors, windows, utility penetrations, and foundation cracks. Address active insect pests promptly because indoor spider populations track prey availability. Switch exterior lights to yellow or warm LED bulbs that attract fewer flying insects, and position outdoor lighting away from doors and windows. Inspect and shake out shoes, gloves, and clothing left in garages, basements, sheds, and storage areas. Trim shrubs and ground cover away from the foundation, and keep firewood and debris stacks at least twenty feet from the structure.

Frequently Asked Questions

Is it normal to have spiders in your house?

Yes. Having some spiders in your home is completely normal and is not a sign of poor housekeeping or structural problems. Most homes contain a few resident spiders, typically harmless species like house spiders and cellar spiders. They provide natural pest control by catching flies, mosquitoes, and other insects.

How many spiders are too many in a house?

There is no magic number, but if you are regularly seeing multiple spiders per day in living spaces, finding webs reappearing quickly after removal, or discovering egg sacs indoors, you may have a population that warrants management. Focus on exclusion and habitat modification rather than trying to eliminate every last spider.

What kind of spiders live in houses?

The most common indoor spiders include house spiders, cellar spiders, cobweb spiders, and sac spiders. In certain regions, brown recluses and black widows may also inhabit homes, particularly in undisturbed areas like basements, attics, and closets. Identifying the species present is the first step in deciding whether action is needed.

Will keeping my house clean prevent spiders?

Regular cleaning helps reduce spiders by removing webs, egg sacs, and prey insects. However, even immaculately clean homes can have spiders because they enter from outside seeking shelter. Cleaning is most effective when combined with exclusion (sealing entry points) and reducing outdoor conditions that attract spiders near the house.