The blockage restricts the diversion of roof runoff. This results in uncontrolled water dispersion adjacent to the building's perimeter, significantly increasing the risk of soil saturation, hydrostatic pressure buildup, and subsequent moisture intrusion into the sub-grade structure.

If the clog is near the entrance of the pipe, a powerful shop vac can often suck out the debris. Disconnect the downspout from the underground pipe. Remove any standing water from the pipe. Insert the vacuum hose and create a seal using a rag. Switch to "suction" mode to pull out leaves and silt. Method B: The High-Pressure Water Jet

Attempting to clear an underground clog with a garden hose often pushes the blockage deeper. Professional routing or high-pressure jetting is usually required to scour the pipe walls and restore proper flow. Addressing a clog early can save you thousands in foundation repairs.