Hoppers are used to bring together a collection of flows into one downpipe. Usually this would be different rainwater pipes from various sections of a roof coming together, such as pipes from a high level roof and a lower roof.This hopper is essentially an open box into which the upper pipes discharge. The lower section of the hopper connects to a 110mm roun downpipe.On occasion if there is a combined system of drainage on much older properties, hoppers are used to feed waste pipes from a bathroom into a rainwater downpipe. As combined drainage systems are no longer in use for new properties this is a much less common use for a hopper.