Rainheads are an essential design element for buildings where internal box or trough gutters are used. A rainhead or sump is a container located between the gutter and downpipe that aids the flow of water away from the roof. It acts as an external overflow point to minimise water surges into the storm water system and aid the flow of water down the downpipe. The outside positioning of rainheads means that they minimise the risk of water overflow inside a building. Furthermore, the addition of an overflow provision provides even greater protection against water overflow in extreme conditions.