Finding dozens of many-legged creatures crawling across your basement floor is unsettling. If you’re asking why are there millipedes in my house, you’re not alone. These slow-moving arthropods are one of the most common “occasional invaders” I encounter in the DC metro area. With over 57 years in business and 1,000+ five-star reviews, I’ve helped countless homeowners understand and solve millipede problems.
The short answer? Millipedes enter homes because of moisture. They require damp environments to survive. When outdoor conditions become too wet, too dry, or too hot, they migrate toward your home seeking relief. The good news is that millipedes are harmless and typically die quickly indoors. Understanding what draws them in can help you prevent future invasions.
Why Millipedes Enter Your Home
Millipedes are moisture-dependent creatures that cannot survive in dry environments. According to NC State Extension, their movement is strongly driven by environmental conditions. When it’s very dry outside, they seek moist places. When it’s very wet, they move to drier spots.
Major nuisance problems usually occur when conditions become too hot and dry. Millipedes then move searching for moisture. Additionally, following heavy rains, thousands may emerge from their normal habitats to breathe. They seek drier places to survive. This is when heavy home invasions occur.
Reason 1: Excessive Moisture Around Your Foundation
The most common reason for millipedes in your house is too much moisture near your foundation. Thick mulch beds, ground cover plants, and leaf litter create perfect millipede habitats right against your home. These same conditions attract slugs, garden snails, and earwigs. When populations build up outside, some inevitably find their way inside.
Areas that trap moisture near your foundation include:
- Heavy mulch applied too close to walls
- Leaf litter accumulated against the house
- Poor drainage causing water to pool near the foundation
- Clogged gutters allowing water overflow
- Dense ground cover plants touching the foundation
Reason 2: Weather Changes and Seasonal Patterns
Why are there millipedes in my house suddenly? Weather shifts are usually the trigger. Millipedes become most active during moderate temperatures. They respond strongly to moisture changes. In my experience working across Northern Virginia and Maryland, I see the biggest spikes after extended rainy periods followed by sudden dry spells.
What triggers mass millipede migrations?
Research from Alabama Cooperative Extension shows that weather changes often trigger mass millipede migrations. Heavy rainfall followed by dry, hot weather creates perfect conditions for invasions. The millipedes emerge to breathe after flooding. Then they seek shelter as conditions dry out.
Reason 3: Entry Points They Exploit
Millipedes don’t need much space to get inside. Common entry points include:
- Door thresholds (especially sliding glass doors and garage doors)
- Foundation cracks and expansion joints
- Gaps around windows and basement windows
- Utility penetrations where pipes and wires enter
- Concrete block wall voids
- Weep holes in brick exteriors
Identifying Millipedes vs. Centipedes
Many homeowners confuse millipedes with centipedes, but they’re quite different creatures. Knowing which pest you have matters because their behaviors and treatment approaches differ.
Millipedes have:
- Two pairs of legs per body segment positioned directly under their body
- Rounded, worm-like body shape
- Slow, deliberate movement patterns
- Curl into a ball when threatened
Centipedes have:
- One pair of legs per segment positioned on the sides
- Flatter body profile
- Fast, darting movements
- Will bite if cornered (millipedes cannot)
According to the Carnegie Museum of Natural History, the leg placement is the easiest way to tell them apart. Millipede legs point down at the ground, while centipede legs extend outward from the body.
Are Millipedes Dangerous?
I often get asked if millipedes in the house pose any danger. The answer is no. Millipedes are completely harmless to humans and pets. According to Orkin, they don’t have venom glands and can’t bite or sting.
Defensive Secretions
Some millipede species release a defensive fluid when threatened. This fluid contains compounds that can cause mild skin irritation, temporary staining, and eye irritation if you handle them directly. While not dangerous, it’s best to avoid touching millipedes with bare hands.
What millipedes don’t do:
- Bite humans or pets
- Transmit diseases
- Damage wood or fabric
- Contaminate food
- Breed indoors
The only real concern with millipedes is the nuisance factor when they invade in large numbers. There’s also potential for staining if they’re crushed on light-colored surfaces.
In fact, most millipedes in my house situations I encounter relate back to moisture. Here’s a case study that illustrates this point:
My Experience: Solving a Basement Millipede Problem
One homeowner I spoke with had a persistent millipede problem in her basement. After an inspection, I discovered that high soil moisture around her home caused the issue.
The soil stayed constantly damp due to poor grading. Water flowed toward the foundation instead of away from it. Additionally, she had thick mulch piled directly against the basement walls. By addressing the drainage, pulling mulch back 12 inches, and sealing basement window gaps, I eliminated the recurring invasions within a few weeks.
Millipede Removal Solutions
Getting rid of millipedes in your house requires a two-pronged approach: removing the ones already inside and preventing new ones from entering.
Step 1: Remove Existing Millipedes
For immediate removal, the simplest approach is vacuuming or sweeping them up. Penn State Extension recommends using a wet/dry vacuum as the fastest and most appropriate control method. Place collected millipedes in a sealed plastic bag and dispose of them in an outdoor garbage container.
The good news? Millipedes generally won’t last long inside your home. According to NC State Extension, because of their moisture requirements, they typically die indoors within a few days unless there are very moist or damp conditions present.
Step 2: Seal Entry Points
Preventing millipedes in your house means blocking their access. Focus on:
- Foundation cracks - Fill with quality exterior caulk
- Door gaps - Install door sweeps and weatherstripping
- Window frames - Caulk around basement and ground-level windows
- Utility penetrations - Seal gaps around pipes and wires
- Expansion joints - Apply flexible sealant
Step 3: Reduce Moisture and Habitat
The most effective long-term solution addresses the moisture conditions that attract millipedes in the first place.
Around your foundation:
- Remove or reduce mulch depth within 6-12 inches of walls
- Clear leaf litter and grass clippings
- Improve drainage so water flows away from the house
- Keep gutters clean and direct downspouts away from the foundation
- Trim ground cover plants back from the foundation
Inside your home:
- Fix any leaking pipes or fixtures
- Use dehumidifiers in damp basements
- Ensure proper ventilation in crawl spaces
- Address any standing water issues
Why gravel barriers work
Research from NC State shows that millipedes rarely cross bare soil or loose materials. Creating an 18-24 inch plant-free barrier of coarse gravel around your foundation significantly reduces millipede migration toward your home. This barrier should be widest on south and west-facing sides where millipedes are most attracted to warm surfaces.
Professional Millipede Treatment Options
While DIY methods work for minor invasions, professional treatment may be necessary when millipedes in your house become overwhelming or keep returning. As a licensed technician at Better Termite & Pest Control, I use a comprehensive approach for stubborn infestations.
Perimeter Treatment
I apply EPA-approved products around the exterior foundation. This creates a barrier that millipedes must cross to enter your home. According to Alabama Cooperative Extension, treatments work best when applied to entry points. These include cracks, crevices, weep holes, utility penetrations, vents, doors, windows, and visible gaps.
Habitat Modification Guidance
Beyond chemical treatment, I help identify moisture issues and habitat conditions that attract millipedes. Sometimes the solution involves addressing drainage problems. Other times, I recommend landscape modifications or point out overlooked entry points.
When to Call a Professional
Consider professional millipede control when:
- Invasions are large (dozens of millipedes daily)
- Problems recur despite DIY efforts
- You can’t locate entry points
- Moisture issues are difficult to resolve
- You want fast, effective results
With 300+ years of combined team experience and membership in the National Pest Management Association, I’ve developed effective protocols for occasional invaders like millipedes.
Preventing Future Millipede Invasions
Once you’ve addressed an active infestation, prevention becomes the focus. Prevention is always easier than treatment. Here’s a seasonal approach to keeping millipedes out of your house:
Spring (March-May):
- Clear winter debris from foundation areas
- Check and repair door sweeps
- Apply fresh caulk to foundation cracks
- Reduce mulch depth near walls
Summer (June-August):
- Maintain dry conditions around foundation
- Keep gutters clear during storms
- Monitor basement humidity levels
- Trim vegetation away from house
Fall (September-November):
- Remove fallen leaves promptly
- Check weatherstripping before winter
- Seal any new cracks or gaps
- Consider preventive perimeter treatment
Get Help With Millipedes in Your Home
If you’re dealing with millipedes in your house and want expert help, I’m ready to assist. With 57 years serving the DC metro area, including Alexandria, Fairfax, Bethesda, and Burke, I’ve helped thousands of homeowners solve pest problems.
Call us at 703-683-2000 or email info@bettertermite.com for a free estimate. I’ll identify why millipedes are entering your home and develop a plan to keep them out for good.
Frequently Asked Questions
Why are there suddenly so many millipedes in my house?
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Sudden millipede invasions typically happen after heavy rainfall or during extreme weather changes. When conditions outside become too wet or too dry, millipedes migrate toward homes seeking more suitable environments. They're drawn to cool, moist areas and often enter through foundation cracks, door thresholds, and gaps around windows.
Are millipedes in my house a sign of moisture problems?
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Yes, millipedes require high humidity to survive. Finding them indoors often indicates excess moisture issues like leaky pipes, poor drainage, or high humidity in basements and crawl spaces. They typically die within a few days indoors unless there's an ongoing moisture problem sustaining them.
Do millipedes bite or harm humans?
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No, millipedes do not bite humans. They lack the mouthparts to do so and feed only on decaying plant matter. Some species release a defensive fluid when threatened that can cause mild skin irritation or staining. Unlike centipedes, millipedes are completely harmless to people and pets.
How can I tell the difference between millipedes and centipedes?
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Millipedes have two pairs of legs per body segment, a rounded body shape, and move slowly. Centipedes have one pair of legs per segment, a flatter body, and move quickly. Millipedes curl into a ball when threatened, while centipedes will run away or bite in defense.
What attracts millipedes to my house?
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Millipedes are attracted to moisture, decaying organic matter, and shelter. Heavy mulch against your foundation, leaf litter, thick ground cover, and damp conditions around your home create ideal habitats. They enter seeking moisture when outdoor conditions become too dry or too wet.
How do I get rid of millipedes in my house?
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For immediate removal, vacuum up millipedes or sweep them outside. Long-term control requires reducing moisture around your foundation, sealing entry points, and removing organic debris like mulch and leaves from near your home. Professional perimeter treatments can create effective barriers.
What time of year are millipedes most common in homes?
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In the DC metro area, millipede invasions peak in late spring after heavy rains and in fall when weather patterns shift. They become active when temperatures are moderate and moisture levels are high. Summer heat and winter cold typically reduce their activity.
Will millipedes damage my home or belongings?
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Millipedes do not damage homes, furniture, or belongings. They don't eat wood, fabric, or food. The only potential issue is the defensive fluid some species release, which can stain light-colored surfaces or fabrics. They're strictly nuisance pests.
How long will millipedes survive inside my house?
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Millipedes generally die within 2-3 days inside homes because indoor environments are too dry for them. They cannot survive without high moisture levels and will quickly desiccate. However, if your home has moisture problems, they may survive longer in damp areas like basements or bathrooms.
Should I call a professional for millipede problems?
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Professional treatment is recommended when millipede invasions are large, recurring, or when you can't identify entry points. Licensed technicians can apply perimeter treatments, identify moisture issues, and seal entry points that homeowners often miss. Most problems resolve with 1-2 targeted treatments.
With five years of hands-on experience in the pest control industry, George Schulz is a registered technician with the Virginia Pest Management Association and a proud third-generation professional in a family business that's been protecting homes for over 57 years. He manages and trains a team of service pros while also leading internal research efforts—recently spearheading a deep-dive review of thousands of documents on pest control materials to hand-pick the most kid and pet friendly, most effective solutions tailored specifically for homes in the DC metro area.