How to Get Rid of Spiders in Your Basement for Good

To safely remove a spider infestation from your basement, clear existing webs, eliminate food sources (other insects), seal all entry points, and apply targeted repellents or pesticides. Consistent prevention—like reducing clutter and controlling moisture—is what stops spiders from returning.

Most basements are a spider’s dream: dark, damp, undisturbed, and full of insects to feed on. A few spiders here and there is normal. But when webs start appearing faster than you can clear them, or you spot egg sacs tucked into corners, you’re dealing with something closer to an infestation.

The good news? You don’t need to call an exterminator right away. Most basement spider infestations can be handled with a methodical approach—clearing, sealing, and preventing. This guide walks you through each step in plain terms, so you know exactly what to do and why it works.

Why Do Spiders Infest Basements?

Before diving into removal, it helps to understand what draws spiders in. Spiders don’t invade homes the way ants or cockroaches do—they’re not after your food. They follow their prey.

Basements attract insects because of moisture, warmth, and easy access through cracks and gaps. Spiders follow the insects. This is why tackling a spider infestation always involves two parallel goals: removing the spiders themselves and eliminating the conditions that brought them there.

Common spider species found in North American basements include:

If you spot a brown recluse or black widow, treat the situation with extra caution. Both species deliver medically significant bites, and a heavy presence of either warrants professional pest control.

Step 1: How to Clear Existing Spider Webs and Egg Sacs

Start with a thorough cleanout. This step removes active spiders, disrupts nesting, and gives you a clear baseline to work from.

What you’ll need:

• A vacuum with a hose attachment
• A broom or duster with an extendable handle
• Disposable gloves
• A sealed plastic bag for disposal

How to clear spiders from your basement:

1. Put on gloves before handling anything.
2. Use the vacuum hose to suck up webs, spiders, and egg sacs directly. A vacuum is more effective than a broom because it captures spiders and their eggs rather than scattering them.
3. Pay close attention to corners, ceiling joints, behind storage boxes, under stairs, and around pipes and ducts—these are high-traffic zones for basement spiders.
4. Immediately after vacuuming, seal the vacuum bag in a plastic bag and dispose of it outside.
5. Use the broom or extendable duster to reach any webs the vacuum missed.

Egg sacs are especially important to remove thoroughly. A single egg sac from a common house spider can contain up to 400 eggs. Leaving even one behind can undo the rest of your work within weeks.

Step 2: How to Eliminate the Spider’s Food Supply

Spiders stay where the food is. Cutting off that food supply—other insects—is one of the most effective long-term strategies for spider control.

Identify and address moisture problems first

Standing water, leaking pipes, and high humidity create the exact conditions that attract insects like fungus gnats, silverfish, and drain flies. Where those insects thrive, spiders follow.

• Use a dehumidifier to keep basement humidity below 50%.
• Fix any plumbing leaks promptly.
• Ensure proper ventilation, especially around windows and vents.

Reduce clutter that harbors insects

Cardboard boxes, old newspapers, and fabric piles are nesting grounds for insects. Replace cardboard storage with sealed plastic bins, and remove any items you no longer need.

Use sticky insect traps

Place sticky traps along the perimeter of your basement floor. These catch crawling insects—and spiders—without chemicals. Check and replace them every few weeks. A high insect count on your traps is a signal that a deeper pest issue needs attention.

Step 3: How to Seal Entry Points to Keep Spiders Out

Spiders enter basements through gaps that are often overlooked. A targeted sealing effort makes a significant difference.

Common entry points for basement spiders

Work your way around the entire perimeter of your basement systematically. Use a flashlight to spot gaps you might otherwise miss—even a crack the width of a credit card is wide enough for most spiders to squeeze through.

Step 4: Apply Targeted Repellents or Pesticides

Once the physical work is done, repellents and pesticides add another layer of protection. You have several options, ranging from natural to chemical.

Natural spider repellents

• Peppermint oil: Spiders are sensitive to strong essential oils. Mix 15–20 drops of peppermint essential oil with water in a spray bottle and apply it along baseboards, window sills, and corners. Reapply every one to two weeks, as the scent fades.
• White vinegar spray: A 50/50 mix of white vinegar and water applied directly to spiders kills them on contact.
• Diatomaceous earth (food grade): Sprinkle this powder along baseboards and in corners. It damages the exoskeleton of spiders and insects, causing dehydration. It’s non-toxic to humans and pets when used as directed.

Chemical pesticide options

For more severe infestations, a residual insecticide spray formulated for indoor spider control is more effective. Products containing bifenthrin or cypermethrin are commonly recommended by pest control professionals for basement use.

Apply along the perimeter, behind shelving, and around the base of walls. Always follow the manufacturer’s instructions, ensure adequate ventilation, and keep children and pets out of the treated area until it has dried completely.

Step 5: How to Prevent Spiders from Returning to Your Basement

Removal without prevention means the infestation will return. These ongoing habits are what make the difference between a one-time fix and a long-term solution.

• Keep the basement clean and decluttered. Regular vacuuming disrupts webs before they become established.
• Install yellow or sodium vapor bulbs near basement windows and exterior entry points. Standard white lights attract insects; yellow bulbs attract significantly fewer.
• Inspect and re-seal annually. Foundations shift, caulk deteriorates, and new gaps appear. A seasonal check—particularly before winter, when spiders seek warmth indoors—keeps your barriers effective.
• Reapply diatomaceous earth or peppermint spray every few weeks as part of your regular cleaning routine.
• Address any recurring moisture issues. Persistent humidity problems often point to drainage or structural issues that require a professional assessment.

When Should You Call a Professional Exterminator?

Most spider infestations respond well to the steps above. Call a licensed pest control professional if:

• You’ve identified brown recluse or black widow spiders in your basement.
• Webs and spiders return quickly despite consistent prevention efforts.
• You suspect the spider infestation is being driven by a larger underlying insect problem you can’t resolve on your own.
• You have mobility limitations or health conditions that make the physical work difficult.

Professional exterminators can apply commercial-grade treatments, conduct a thorough inspection, and identify contributing factors that aren’t always obvious to homeowners.

Take Back Your Basement

Getting rid of a spider infestation in your basement requires more than spraying and hoping for the best. The process works in layers: remove what’s there, cut off the food supply, seal the entry points, apply repellents, and maintain the conditions that make your basement inhospitable to spiders long-term.

Start with the vacuum and a thorough cleanout this weekend. Seal any gaps you find with appropriate materials. Add a dehumidifier if moisture is an issue. These foundational steps alone will make a visible difference within a few weeks—and the prevention habits will keep your basement spider-free for seasons to come.

Frequently Asked Questions

What is the fastest way to get rid of spiders in a basement?

The fastest approach is to vacuum up all visible spiders, webs, and egg sacs, then apply a residual insecticide spray along the basement perimeter. This provides immediate results. For lasting control, follow up by sealing entry points and reducing moisture, which eliminates the conditions that attract spiders.

Are basement spiders dangerous to humans?

Most basement spiders—including cellar spiders, common house spiders, and wolf spiders—are harmless to humans. The exceptions are the brown recluse and black widow, both of which deliver medically significant bites. If you identify either species in your basement, exercise caution and consider contacting a pest control professional.

How long does it take to get rid of a spider infestation?

With consistent effort, most basement spider infestations show significant improvement within two to four weeks. Full resolution depends on the severity of the infestation and how effectively entry points and moisture issues are addressed.

Can spiders come back after treatment?

Yes, spiders can return if the underlying conditions—moisture, insect prey, and accessible entry points—aren’t resolved. Long-term prevention involves regular cleaning, sealing gaps annually, and maintaining low humidity. Periodic reapplication of repellents like diatomaceous earth also helps.

How do I know if I have a spider infestation vs. just a few spiders?

Signs of a spider infestation include multiple webs appearing regularly in the same areas, visible egg sacs, frequent sightings of live spiders (especially different species), and a high count of insects on sticky traps. Seeing one or two spiders occasionally is normal; recurring, widespread activity suggests an infestation.