Identify
What are termite mud tubes?
Termite mud tubes are pencil-width lines of soil on concrete, brick, or wood. Subterranean termites build them so workers can walk from moist ground to the house without drying out.
Break one inch, photograph first, and wait a few days. A patch or live cream-colored workers means the route is still in use.
Key takeaways
- About the width of a pencil, soil and saliva, from the ground up to wood.
- Break one inch. Live workers or a repair in the next days means active.
- An empty, dry tube does not mean the colony left. They abandon sections while they feed elsewhere.
- Scraping the tube off does not kill the colony. Most of it stays in the soil.
- Photograph before you scrape. Inspectors read the path.
No other common house pest builds this. If the line is soil, about a pencil thick, and it climbs from grade toward wood, you are looking at a shelter tube.
Break one inch. Wait.
Mississippi State: break about an inch, watch for workers, then come back. A repair in the next few days means the colony is still using that path. Destroying the whole tube does not control the termites. They are in the ground. They will find another way in.
Kentucky: creamy-white workers inside a fresh break are the active tell. A vacant tube does not prove the job is over. Foragers leave a section while they feed somewhere else in the building.
Fresh tubes look darker and hold together. Old ones go tan and crumble. Color alone is a weak test. The repair is the test.
Leave the map on the wall
Photograph with a coin or a ruler. Note the side of the house. Then scrape a small window if you need to see inside. Do not paint over the run if a sale or a warranty clock is running.
Look on the exterior foundation, crawl piers, basement where concrete meets the sill, garage expansion joints, and around plumbing that comes through a slab. Tubes higher on a wall or through foam insulation are a reason to ask about Formosan pressure in Gulf and southern states. MSU flags those as a professional inspection, not a weekend spray.
Mud-dauber nests are organ-pipe clusters under an eave, not a line from soil to sill. Rain splash is a blotch, not a continuous climb.
Drywood termites skip tubes. They live in the wood and kick out pellets.
Log the photo in the sighting log. Read termite treatment cost after a licensed look. Contact for a referral path. Typical US ranges, not a bid. Shelf sprays do not replace a soil treatment or a bait system.