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?

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 meter to assess dampness levels in suspect areas, and inspect plumbing and drainage systems for potential leaks.

Upon spotting suspected mud tubes, take immediate action to prevent further damage. Limit disturbance to the tubes, as termites are sensitive to changes