A rain gutter (also known as eaves trough, guttering or simply as a gutter) is a narrow channel, or trough, forming the component of a roof system which collects an diverts rainwater shed by the roof. In many buildings, the purpose of this diversion is to prevent water from falling off the roof edges. This uncontrolled water can cause structural damage to the outside walls and/or the foundation of a building over time. Another purpose of rain gutter is to harvest rainwater for household or garden use.