A spider infestation occurs when spiders establish a breeding population inside your home, moving beyond isolated sightings to consistent activity across multiple rooms or areas. Common signs of a spider infestation include increased web activity, egg sacs in sheltered spots, regular live sightings, and a rise in the insect activity spiders feed on.
Most spider infestations are driven by three conditions: available food (other insects), undisturbed harborage (clutter, cardboard, dark corners), and easy access from outside through gaps in the building. Addressing all three is the most reliable way to address a spider infestation and help prevent it from returning.
What is a spider infestation?
A spider infestation happens when spiders establish themselves inside your home in numbers large enough to reproduce and persist without intervention. Unlike a stray spider that wanders in through an open door, an infestation involves an active population feeding, nesting, and producing egg sacs in your walls, storage areas, or basement.
The threshold varies, but consistent sightings in multiple locations, egg sacs in sheltered spots, and evidence of regular feeding activity are all indicators that you're dealing with more than a one-off encounter.
10 signs of a spider infestation in your home
Since spiders are largely nocturnal and prefer undisturbed spaces, they can build up a significant presence before most homeowners notice. Here are the key signs of a spider infestation to look for.
1. More webs than usual
An increase in web activity — especially in corners, behind furniture, along ceiling lines, or in storage areas — is the most visible sign that spider numbers are growing. Different species build different web styles, from the classic orb web to flat sheet webs and irregular tangles close to the floor.
2. Egg sacs
These are small silk-wrapped balls, typically white or cream, and they can hold anywhere from a handful to several hundred eggs depending on the species. Finding egg sacs near baseboards, inside cardboard boxes, or beneath shelving means a population is actively reproducing in your home.
3. Frequent live sightings
Spotting spiders regularly, particularly during the day when most species prefer to stay hidden, suggests a larger population pushing individuals into less-preferred areas.
4. Dead spiders and shed skins
Spiders moult as they grow. Finding shed skins along with dead spiders in undisturbed spots indicates an established, cycling population rather than isolated individuals.
5. Spider droppings
These look like small dark specks and tend to accumulate directly below active hiding or feeding spots. Finding them consistently in the same areas points to regular spider activity overhead.
6. Dead insect accumulation
Dried, hollowed-out insects near baseboards or in storage areas are a sign of active spider feeding. If you're finding insect remains without obvious flies, moths, or other live insects nearby, a spider is likely the explanation.
7. Increased insect activity overall
Spiders follow their food source. A noticeable uptick in flies, gnats, moths, or other small insects inside your home creates the exact conditions that attract and sustain a spider infestation in your house.
8. Musty smell in closed-off spaces
Stale air combined with high moisture in attics, basements, or rarely-used storage rooms creates ideal spider habitat. A persistent musty odor in these spaces often correlates with elevated insect and spider activity.
9. Bite marks you can't explain
Most spider bites happen incidentally — reaching into a dark space or sleeping near a spider in a piece of furniture. Unexplained bite marks on the skin, particularly if they appear reddened or irritated, are worth investigating alongside a check of your home's common hiding spots.
10. Finding spiders in clothing or shoes
Finding spiders tucked inside your clothing or shoes is a primary indicator that a larger, hidden infestation is developing within your home's low-traffic areas. This behavior occurs because spiders actively seek out dark, enclosed, and undisturbed spaces that mimic the protective natural crevices they hunt in.
What causes a spider infestation?
Spiders don't move into a home randomly. Conditions that make survival easy is what attracts spiders to your house. Understanding those conditions is the most direct path to learning how to get rid of a spider infestation and keeping it from coming back.
- Insect activity is the primary driver: A home with significant fly, moth, gnat, or cricket activity signals to spiders that there's a reliable food supply available. Solving the insect problem often reduces the spider problem alongside it.
- Clutter creates harborage: Cardboard boxes, piles of clothing, stacked firewood stored indoors, and dense storage areas all provide the undisturbed, sheltered spaces spiders prefer for nesting and egg-laying. The more clutter, the more viable territory for a spider population to expand.
- Moisture and humidity: Damp environments — basements, crawl spaces, bathrooms with poor ventilation — replicate the cool, sheltered conditions spiders seek out. High humidity also supports the insect populations spiders feed on, compounding the issue.
- Unsealed gaps and entry points: Cracks in the foundation, gaps around window frames, spaces under doors, and openings around utility pipes all give spiders direct access from outside.
- Seasonal migration: Spider activity indoors typically peaks in late summer and fall as outdoor temperatures drop and spiders seek warmth. What starts as a few individuals moving inside can establish a larger population quickly if conditions inside are favorable.
Which spiders should you be most concerned about?
Most indoor spiders are harmless and primarily a nuisance. Common species like cellar spiders, house spiders, and jumping spiders are not medically significant and generally cause no harm beyond the webs they leave behind.
Two species warrant more serious attention:
- Brown recluse spiders: Found primarily in south-central states including Missouri, Kansas, Oklahoma, Arkansas, and Texas. They are small, tan to dark brown, and identifiable by the violin-shaped marking on their backs. Their venom can cause localized tissue damage in some cases. They prefer undisturbed storage areas, cardboard boxes, and rarely-used clothing. The most common signs of brown recluse infestation are irregular, low-to-ground webs in storage areas, frequent sightings at night, and finding the spiders in shoes, boxes, or folded clothing.
- Black widow spiders: Found across much of the United States and identifiable by the red hourglass marking on the underside of the female's abdomen. Their venom affects the nervous system and can cause significant symptoms in children, the elderly, or individuals with underlying health conditions. Signs of black widow infestation include discovering small, marble-sized silk egg sacs and irregular, tangled webs built near ground-level crevices, dark corners, or messy storage areas.
If you're seeing spiders that resemble either of these species, professional identification and treatment should be prioritized over DIY approaches.
* The content in this article is provided for informational purposes only and is not intended as medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider regarding any medical condition. Do not delay seeking emergency care for severe allergic reactions such as difficulty breathing or swelling of the face or throat. Individual reactions to wasp stings may vary, and no guarantees are made regarding the effectiveness of any treatment described. Home remedies mentioned are not medically verified and may cause adverse reactions.
Aptive Environmental LLC provides pest control services only and does not offer medical advice. The company is not liable for any damages or injuries resulting from the use of this information.
How to prevent a spider infestation
Preventing a spider infestation in your house comes down to removing the conditions that make your home attractive in the first place.
- Seal entry points: Apply caulk and expanding foam seal to the most common routes spiders use to get inside. Focus on foundation gaps, window frames, door sweeps, and anywhere utilities enter the building.
- Reduce and organize clutter: Replace cardboard boxes with sealed plastic bins in basements and storage areas. Keep floors clear in closets and garages. The less undisturbed harborage space available, the fewer places a spider population can establish.
- Maintain your exterior: Trim shrubs, vines, and ground cover away from the house. Relocate woodpiles at least 20 feet from the structure. Vegetation and wood stacked against the home creates a direct bridge for spiders moving indoors.
- Vacuum consistently: Regular vacuuming removes webs, egg sacs, and the insects that attract spiders. Pay attention to corners, behind furniture, under beds, and along baseboards. Empty the vacuum bag or canister outside immediately afterward.
- Use yellow exterior lighting: Standard white exterior lights attract insects at night. Switching to yellow sodium vapor bulbs significantly reduces insect congregation around entry points, removing a key food source that draws spiders close to your home. Understanding where and when spiders are most active can help you time prevention efforts through the year.
How to get rid of a spider infestation
The right approach depends on the scale of the problem and the species involved.
Homeowners may use DIY methods to help with early-stage or low-level activity Sticky traps placed along walls and in corners catch spiders moving at night and can give you a clearer picture of activity levels. Diatomaceous earth applied along baseboards and entry points dehydrates spiders on contact. Essential oils like peppermint or eucalyptus may discourage spiders in treated areas, though they won't eliminate an established population.
However, while these DIY methods may seem like easy steps to apply to a spider infestation, home remedies have limits. Essential oils may discourage spiders from treated surfaces but won't eliminate an established population or address the food source driving the spider infestation.
Professional spider control is the more reliable option once a population is established. Trained technicians identify harborage sites, assess the scale of the spider infestation, and apply targeted residual treatments to areas DIY products don't reach effectively. Aptive's spider pest control service includes inspecting your property for signs of a spider infestation, entry point identification, and interior and exterior treatment.
If prevention steps haven't been enough or you're already dealing with an active spider infestation, Aptive's trained service professionals can assess your home, identify problem areas, and deliver targeted treatment that addresses the population at its source. Get a quote from Aptive and take back your home today.
Spider infestation FAQs
Q: How do I know if I have a spider infestation?
A spider infestation includes consistent sightings in multiple rooms over several weeks, egg sacs tucked into sheltered spots like storage boxes or behind furniture, spider droppings accumulating in the same areas, and dead insects near baseboards from active feeding. If two or more of those are present together, you are likely dealing with an established population.
Q: What attracts spiders to my house?
The main draw is other insects. Spiders follow their food source, so a home with high fly, moth, or gnat activity is signaling to local spiders that there's a reliable supply available. Beyond food, spiders are attracted to undisturbed clutter that provides harborage, moisture in basements and crawl spaces, and any gaps or cracks that make entry easy. Remove those conditions and your home becomes a significantly less appealing place to settle.
Q: Can a spider infestation go away on its own?
It is unlikely that a spider infestation will go away without some form of intervention. Spiders can survive for months without food and reproduce steadily through the warmer months, with egg sacs holding dozens to hundreds of eggs depending on the species. Without addressing the food source, harborage, and entry points driving the infestation, the population has little reason to leave. In most cases, conditions either stay the same or gradually improve for the spiders, not the homeowner.
Q: Are house spiders dangerous?
The vast majority of common house spiders pose no medical risk. Species like cellar spiders, jumping spiders, and common house spiders are largely harmless and are more of a nuisance than a threat. The two species that require more serious attention in the US are the brown recluse – found primarily in south-central states, and the black widow – found more broadly across the country. Both are identifiable by distinct markings and warrant professional treatment if confirmed.
Q: When should I call a spider control professional?
If you've found egg sacs in more than one location, identified or suspect a black widow or brown recluse infestation, or tried DIY methods for several weeks without reducing sightings, professional treatment is the right move. A trained technician can locate harborage sites that aren't obvious, assess the full scale of the spider infestation, and apply residual treatments that reach areas standard consumer products typically don't. Early intervention makes the process faster and less disruptive.
