During rain, water spills over the sides of the gutters instead of flowing into the pipe.
When water cannot go down, it must go somewhere. The hydrostatic pressure builds until water overflows the back lip of the gutter.
A downpipe is a pipe that connects the gutter system of a building to the ground, allowing water to flow freely from the roof to the drainage system. Its primary function is to direct water away from the foundation of the building, preventing damage to the structure and surrounding landscape. Downpipes, also known as downspouts, are typically made of metal, vinyl, or plastic and come in various shapes and sizes.