The most common sign of termites in Maryland is the presence of mud tubes along the home’s foundation, as advanced signs, such as hollow-sounding wood or visible damage, typically don’t appear until years after a colony has been established.
Termites cause more structural damage to U.S. homes each year than fires and floods combined, yet most homeowners don’t know they have them until the damage is already done.
The reason is simple: the eastern subterranean termite, Maryland’s most common species, lives underground and feeds inside your walls and floors without ever breaking the surface.
According to the USDA, the average infestation causes over $3,000 in structural damage before it’s discovered, and that number climbs fast when a colony goes undetected for three or more years. Knowing what to look for is the only way to catch them early.
The following signs of termite activity in Maryland are listed in the order you’re most likely to encounter them, from the earliest indicators to the damage signs that appear later. Finding even one of them is reason enough to call a professional the same day to curtail infestations and avoid expensive repairs.
Sign 1: Mud Tubes on Your Foundation Walls
Mud tubes are small, pencil-sized tunnels that termites build out of dirt and wood to connect colonies and protect themselves from predators.
Look for them on your foundation walls, crawlspace piers, the underside of floor joists, and along interior basement walls. They’re usually about the width of a pencil and follow a path upward from the soil.
If you break one open and find small, pale insects inside, that’s an active colony. An empty tube still needs to be professionally inspected, since colonies often abandon and rebuild nearby.
There is no harmless explanation for mud tubes on your home. If you find one, treat it as confirmation of an active problem and call immediately.
Sign 2: Termite Swarmers Inside Your Home
Termite swarmers are the winged reproductive members of a mature colony. When a colony gets large enough, it sends swarmers out to find new locations and start new colonies. In Maryland, swarms happen primarily between March and May, usually after a warm rain.
Seeing swarmers outside, near your yard or exterior walls, may indicate a colony is nearby. Seeing them inside, emerging from floors, walls, or window frames, means there’s already an active colony inside or directly under your home.
Swarmers are often mistaken for flying ants. Here’s how to tell them apart: termite swarmers have straight antennae, two pairs of equal-length wings that extend well past their body, and no obvious waist. Flying ants have bent antennae, wings of different lengths, and a clearly pinched waist.
Sign 3: Discarded Wings Near Windows and Door Frames
After termite swarmers find a mate, both shed their wings immediately. The wings pile up wherever the pairing happens. Finding a cluster of small, translucent wings along a windowsill or door frame inside your home is a sign that a swarm has already occurred, possibly without you noticing.
Termite wings are all roughly the same length and are veined and semi-transparent. Finding them means the colony responsible is mature, since colonies don’t produce swarmers until they’re at least two to five years old.
Sign 4: Hollow-Sounding Wood When You Knock on It
Termites eat wood from the inside out, leaving a paper-thin outer layer intact. A structural member that looks perfectly fine from the outside can be almost entirely hollowed out inside.
Tap on baseboards, door frames, window frames, and any exposed wood in your basement or crawlspace with your knuckle or a screwdriver handle.
Sound wood makes a dense, solid thud. Termite-damaged wood sounds hollow or papery. If it sounds hollow, press a screwdriver tip firmly into the surface.
Termite-damaged wood will let the screwdriver punch through with almost no resistance, revealing a network of tunnels running along the grain.
Sign 5: Paint That’s Bubbling or Looks Uneven
When termites feed inside a wall, they produce moisture as a byproduct of digesting wood. That moisture builds up inside the wall cavity and pushes outward, causing paint to bubble, blister, or look wavy. It can look like a water leak, but there’s no plumbing nearby.
The key difference between termite moisture and a plumbing leak: termite-related bubbling tends to appear in isolated patches on interior walls, often near the floor, and worsens in spring when termite activity peaks, rather than correlating with rainfall.
If you see bubbling paint alongside any other sign on this list, that combination is a strong indicator of an active infestation.
Sign 6: Doors and Windows That Suddenly Start Sticking
The same moisture that causes paint to bubble also causes wood frames to swell. When termites are feeding inside a door or window frame, the surrounding wood absorbs the moisture they produce and warps, making the door or window harder to open or close.
This is easy to dismiss as a humidity problem, especially in Maryland’s humid summers. But if a door that never stuck before starts sticking at a specific corner, or if sticking shows up alongside any other sign on this list, the frame should be inspected rather than planned or adjusted.
Sign 7: Small Piles of Frass Near Wood or Along Baseboards
Frass is the technical term for termite excrement. While it’s a clear sign of an infestation, the way it appears tells you exactly which type of termite has moved in.
- Drywood Termites: These termites are rare in Maryland but can hitch a ride into your home via infested furniture. They live inside the wood, they eat and “kick out” their waste through tiny holes to keep their galleries clean. This results in small, concentrated piles of six-sided pellets that look like mounds of coarse sawdust or coffee grounds.
- Subterranean Termites: This is the primary species in Maryland. Unlike their drywood cousins, they don’t leave piles of droppings. Instead, they mix their frass with soil and saliva to construct mud tubes, which they use as protected highways to travel between the ground and your home’s wood.
If you find piles of material that look like sawdust near baseboards or wooden structures, it is a significant red flag. Whether it is drywood termites, carpenter ants, or even wood-boring beetles, finding frass is a definitive reason to schedule a professional inspection to confirm the source before structural damage worsens.
Sign 8: Floors That Sag, Bounce, or Feel Soft Underfoot
A floor that sags in one area, bounces when you walk across it, or feels spongy underfoot has lost structural integrity underneath. At this point, the infestation has been going on long enough to significantly weaken floor joists or subfloor sheathing.
Floor joists that termites have hollowed out can no longer bear normal loads properly. The floor above begins to flex and eventually deflect visibly. If you’re seeing this, the infestation is not in its early stage. You need both a pest control professional and a structural contractor involved immediately to assess the damage.
Sign 9: Pinholes in Drywall or Tunnels Under Wallpaper
When termites feed inside a wall and push through to the drywall surface, they leave behind tiny holes roughly the size of a finishing nail, often surrounded by brown, muddy material. This is different from standard wall damage, which would be clean inside.
Wallpaper can show termite activity in different ways: long, thin ridges or raised tunnel shapes running across the surface indicate that termites have built galleries directly beneath the paper. This is one of the more subtle signs and is frequently dismissed as wallpaper adhesion failure until an inspection confirms what’s actually underneath.
Sign 10: Live Termites in Soil or Wood on Your Property
Actually seeing a termite is less common than seeing their damage, because workers avoid light and dry conditions. But if you disturb the soil near your foundation, move mulch or firewood against the house, or break apart rotting wood in your yard and find small, pale, soft-bodied insects moving through connected tunnels, those are most likely termite workers.
Workers are cream to pale yellow, about 1/8 to 3/8 of an inch long, and scatter when exposed to light. Finding them in soil adjacent to your foundation doesn’t necessarily mean they’re already inside, but it confirms an active colony nearby.
Any wood-to-soil contact along your foundation, any moisture at the foundation line, and any existing cracks in the foundation are all factors that determine how quickly they’ll get in if they haven’t already.
What to Do If You Spot Any of These Signs
Call a licensed pest control professional before touching anything. Don’t disturb mud tubes, break apart damaged wood, or spray over-the-counter products on visible termites. Disturbing the colony can cause it to scatter deeper into the structure, making it harder to locate and treat.
Consumer sprays applied to surface termites do nothing to address the underground colony and often make professional treatment more difficult.
The most effective treatment for eastern subterranean termites in Maryland is the Sentricon Always Active bait system. Stations are installed in the soil around your home’s perimeter.
Termite workers find the bait during normal foraging, carry the active ingredient back to the colony, and share it with other workers through normal feeding behavior. Over time, the compound collapses the colony from within. Sentricon is the only termite treatment ever awarded the U.S. EPA’s Presidential Green Chemistry Award.
The sooner you act, the less expensive the outcome. A colony caught in year one costs a fraction of what it costs to treat and repair a home where termites have been active for five years or more.
Frequently Asked Questions
How do I tell the difference between termites and carpenter ants?
Both damage wood, but they do it differently. Carpenter ants hollow out wood to build nests, but don’t eat it.
They leave behind coarse, gritty frass that often contains insect body parts, and their galleries are smooth and clean. Termites eat the wood itself along the grain, leaving galleries packed with mud and no clean surfaces. Mud tubes are the definitive tell: carpenter ants don’t build them. If you see mud tubes, you have termites.
How long does it take for termites to cause serious damage in Maryland?
Visible structural damage typically appears 3 to 5 years after a colony gets established. A large or fast-growing colony can accelerate that timeline.
The USDA estimates the average colony causes over $3,000 in damage before discovery. Costs rise steeply the longer the problem goes unaddressed, which is why annual inspections matter even when you see no signs.
Are termites active in Maryland during winter?
Eastern subterranean termites don’t hibernate. In colder months, the colony moves deeper underground where soil temperatures stay warmer.
But if termites are already feeding inside a heated structure, their activity doesn’t slow down at all. Annual inspections are appropriate year-round, not just in spring and summer.
Does homeowner’s insurance cover termite damage in Maryland?
Standard homeowner’s insurance policies specifically exclude termite damage, treating it as a preventable maintenance issue rather than a sudden loss. The full cost of treatment and any structural repairs falls on the homeowner.
That makes early detection and ongoing prevention the most financially protective approach available.
How often should I have my home inspected for termites?
Once a year is the standard recommendation for Maryland homeowners. Homes with a history of termite infestations, wood-to-soil contact at the foundation, known moisture issues, or those adjacent to wooded areas should consider more frequent monitoring.
An ongoing prevention plan with bait-station monitoring is the most reliable way to detect new activity before it becomes a structural problem.
Spotted Signs of Termites? Schedule An Inspection Today!