Found these strange dirt-like veins running up my basement wall. They crumble when touched but seem hollow inside. Do I have a leak or something else?

That Mimic Mud Tubes
While mud tubes are a primary concern, moisture issues can mimic their appearance. Leaks can cause efflorescence, mold growth, or water streaks that may be mistaken for termite activity.
If the substance is powdery and does not crumble into chunks, or if you notice water stains or dampness, a hidden leak may be the cause. Use a moisture continue reading …