Terms for RRain downpipe / downspout
Receiving water courses
Replenishing / system control
Roof runoff water
During rainwater containment (including retention) rainwater is retained in a temporary storage vessel and is restrictedly drained off from there into a public sewer or similar. In this way, peak loads in the sewer and thus local flooding are avoided. Rainwater retention can be achieved by retention cisterns or French drain systems. In heavy rain, the water level rises in the system and is routed into the sewer delayed via a throttle.