When you think about pest problems in your home, you probably picture ants in the kitchen, spiders in the corners, or mosquitoes in the backyard.

But some of the most serious pest issues don’t happen in the parts of your home you see every day. They happen beneath your property – in basements, crawlspaces, and the areas under your foundation where pests can hide, nest, and cause damage without you knowing about it.

These below-ground spaces create the perfect environment for certain pests. They’re dark, often damp, and usually undisturbed, which means pests can establish themselves long before you notice any signs of activity. By the time you discover the problem, the infestation may already be extensive.

ExtermPRO provides comprehensive pest control for basements, crawlspaces, and below-ground areas throughout Northern Virginia. We help homeowners identify, eliminate, and prevent the pests that thrive in these hidden spaces, protecting your home from damage and keeping your property safe.

If you’ve noticed signs of pest activity in your basement or crawlspace, or if you want to prevent problems before they start, contact ExtermPRO today at 571-620-1168 for a free inspection.

Why Pests Love Basements and Crawlspaces

Basements and crawlspaces are attractive to pests for several reasons. These include:

• Moisture and Humidity — Many pests are drawn to moisture, and basements and crawlspaces tend to be more humid than the rest of your home. Poor ventilation, water intrusion, leaking pipes, and condensation all create damp conditions that pests need to survive.
• Darkness — Most pests prefer to stay hidden and avoid light. Below-ground spaces are naturally dark, which makes them ideal hiding spots for pests that want to avoid detection.
• Limited Human Activity — You probably don’t spend much time in your crawlspace, and even basements are often used less frequently than other parts of the home. This lack of activity gives pests a safe, undisturbed environment where they can nest and reproduce.
• Access Points — Foundation cracks, gaps around pipes and utility lines, vents, and floor drains all create entry points for pests to get into your basement or crawlspace from the outside. Once they’re in, they have easy access to the rest of your home.
• Food and Shelter — Stored items in basements, insulation in crawlspaces, cardboard boxes, and organic debris all provide food or nesting materials for pests. Even the wooden structural elements of your home can be a food source for certain pests like termites.

It’s also not necessarily that pests are more drawn to these areas, they may simply have an easier time getting there. These access points tend to be a lower level – where more pests travel – allowing them to enter without any dangerous or difficult climbs that put them at risk of predators.

Common Pests Found in Basements and Crawlspaces

Different pests are drawn to below-ground spaces for different reasons. Here are the most common pests you’re likely to encounter in your basement or crawlspace, and why they’re there.

Rodents (Mice and Rats)

Rodents are one of the most common pests found in basements and crawlspaces. They’re looking for shelter, warmth, and food, and the dark, quiet spaces beneath your home provide all three.

Mice can squeeze through openings as small as 1/4 inch, which means even tiny gaps in your foundation or around utility lines are enough for them to get inside. Once they’re in, they nest in insulation, chew through wiring and pipes, contaminate stored items, and reproduce quickly. A small mouse problem can become a serious infestation in just a few weeks.

Rats are larger and more destructive, but they’re equally attracted to basements and crawlspaces. They can cause extensive structural damage, carry diseases, and create fire hazards by chewing through electrical wiring.

Signs of rodents in your basement or crawlspace:

• Droppings (small, dark pellets)
• Gnaw marks on wood, wires, or pipes
• Shredded insulation or nesting materials
• Greasy rub marks along walls
• Scratching or scurrying sounds

Termites

Termites are one of the most destructive pests that can infest your crawlspace. Subterranean termites live underground and build mud tubes up through your crawlspace to access the wooden structural elements of your home. Because crawlspaces are dark and often damp, they provide the perfect conditions for termites to thrive.

Termites feed on wood 24 hours a day, and they can cause significant structural damage before you even realize they’re there. By the time you see signs of termite activity inside your home, the infestation may have already been present for months or even years.

Signs of termites in your crawlspace:

• Mud tubes on foundation walls or floor joists
• Damaged or hollow-sounding wood
• Discarded wings near windows or doors
• Sagging floors or visible structural damage

Spiders

Many spider species prefer dark, undisturbed areas like basements and crawlspaces. While most spiders are harmless, some species – like black widows and brown recluses – can be dangerous, and even harmless spiders can create unsightly webs and become a nuisance.

Spiders are also an indicator of other pest problems. If you have a lot of spiders in your basement or crawlspace, it’s because they’re feeding on other insects. Eliminating the insects they prey on will help reduce the spider population.

Signs of spiders in your basement or crawlspace:

• Webs in corners, along walls, or in ceiling joists
• Egg sacs (small, silk-covered bundles)
• Shed spider skins
• Live or dead spiders

Crickets

Crickets are attracted to cool, damp environments, which makes basements ideal habitat. They’re not typically dangerous, but they can be a nuisance – especially when they’re chirping at night – and they can damage fabrics, paper, and other stored items.

Camel crickets (also called cave crickets or spider crickets) are especially common in basements and crawlspaces. They don’t chirp like other crickets, but they reproduce quickly and can become a significant nuisance.

Signs of crickets in your basement or crawlspace:

• Chirping sounds (for field crickets)
• Visible crickets, especially at night
• Damage to stored fabrics or paper products

Silverfish

Silverfish thrive in damp, dark environments with high humidity levels. Basements provide the perfect conditions for them to survive and reproduce. While silverfish don’t bite or spread disease, they damage paper products, books, photographs, wallpaper, and fabrics.

If you have stored items in your basement – especially cardboard boxes, old books, or clothing – silverfish can cause significant damage over time.

Signs of silverfish in your basement:

• Small, silver, fish-shaped insects
• Yellow stains or scales on surfaces
• Damage to paper, books, or fabrics
• Holes in wallpaper or cardboard

Centipedes and Millipedes

Centipedes and millipedes are attracted to moisture and often enter basements and crawlspaces through foundation cracks or floor drains. While they’re generally harmless, they can be alarming to encounter, and large populations indicate underlying moisture problems.

House centipedes are particularly common in basements. They feed on other insects, so if you have centipedes, it’s a sign that you may have other pest problems as well.

Signs of centipedes or millipedes:

• Live centipedes or millipedes, especially near drains or damp areas
• Dead centipedes or millipedes near walls or corners
• Frequent sightings, especially after rain

Cockroaches

Some cockroach species – particularly American cockroaches and Oriental cockroaches – prefer basements and crawlspaces. These areas provide the moisture, food, and shelter that cockroaches need to survive.

Cockroaches can spread bacteria, contaminate food, trigger allergies and asthma, and reproduce quickly. If you see one cockroach in your basement, there are likely many more hiding nearby.

Signs of cockroaches in your basement:

• Live or dead cockroaches
• Droppings (small, dark specks)
• Egg cases (small, brown capsules)
• Musty odor

Carpenter Ants

Carpenter ants don’t eat wood like termites do, but they excavate it to build their nests. They’re attracted to moist, damaged wood, which is often found in crawlspaces or basements with water damage or poor ventilation.

Carpenter ant infestations can cause structural damage over time, and they’re often difficult to eliminate without professional help because their nests are hidden inside walls or structural wood.

Signs of carpenter ants:

• Large black ants, especially near wood
• Piles of sawdust (frass) near baseboards or wooden beams
• Rustling sounds inside walls
• Damaged or hollow wood

When to Call a Professional

If you’ve noticed any signs of pest activity in your basement or crawlspace, or if you’ve tried DIY methods without success, it’s time to call a professional pest control company.

ExtermPRO specializes in treating below-ground pest problems. We conduct thorough inspections to identify the pests present, locate entry points and conducive conditions, and develop a customized treatment plan to eliminate the infestation and prevent it from returning.

Professional pest control is especially important for:

• Termite Infestations — These require specialized treatment and should never be handled as a DIY project.
• Rodent Problems — Rodents reproduce quickly and can be difficult to eliminate completely without professional help.
• Large or Recurring Infestations — If you’re seeing pests frequently, or if they keep coming back after treatment, professional intervention is necessary.
• Pests That Pose Health Or Safety Risks — Cockroaches, rodents, and some spiders can create health hazards that require professional treatment.

Your basement and crawlspace may be out of sight, but they shouldn’t be out of mind when it comes to pest control. These spaces are vulnerable to infestations that can cause structural damage, health risks, and serious frustration if left untreated.

By monitoring for signs of activity, maintaining your below-ground spaces, and working with a professional pest control company like ExtermPRO, you can protect your home from the pests that thrive in dark, damp, hidden areas.

If you’re dealing with pests in your basement or crawlspace, or if you want to schedule a preventive inspection, contact ExtermPRO today at 571-620-1168. We serve Gainesville, Bristow, Warrenton, Haymarket, Centreville, and surrounding Northern Virginia communities, and we’re here to help you keep your entire property pest-free – including the spaces you don’t see every day.