Eavestroughs & Downspouts The volume of rain an eavestrough can handle is altered when the eavestrough is clogged with obstructions such as leaves or surface particles from asphalt shingles. Dented or bent downspouts will also slow the flow of water. Remove debris from your eavestroughs each spring, so water can move efficiently from the roof and away from your home’s foundation. Why do my eavestroughs overflow during normal rain conditions? ROOFING 75