The purpose of the building’s rainwater drainage system is to divert rainwater from the roof, so that it does not collect in puddles in the courtyard and endanger the foundation and basement. Rainwater is channelled through gutters and downpipes to rainwater collectors at ground level, from where it is channelled to stormwater pipes. The rainwater pipes used are smooth on the inside, waffled on the outside and not perforated.
The stormwater drainage system is kept separate from the building drainage system, as the drains, filled with floodwater, would push the water towards the foundation walls of the building and the piping would work in the opposite direction to what is needed.
Rainwater is discharged to a
downstream outlet (e.g. a ditch) or to a main well away from the house.