Drainages are built to expel the waste water from the kitchen or bathroom. It is necessary to build drainage by following vastu shastra rules. The drainages should always be built slanting because if it is not done so it may result in blockage of waste water resulting in foul smell.
Waste water should not be drained off in the south or south west direction. According to vastu shastra, the drainage water should be drained off in the north or east part of the north eastern corner. Always ensure that the waste water is not clogged.