The floor level towards East, North & NorthEast being lower level is the best. As also drainage from this area only. If However the lower level of the flooring is not possible complete plinth may be uniform in level. In no case should South, West & SouthWest be at a lower level. SouthEast & NorthWest should be at the same level and slope shall always be SouthWest towards NorthEast only. Bia underground piping, drain water from NorthEast can be taken out towards any direction.