Section 166(3) in West Bengal Municipal (Building) Rules, 2007
(3)(a)Septic tank soak pits shall be so located so as to be easily accessible from the means of access to the plot;(b)soak pits may be constructed on the side of buildings at right angles to the slope of the land and from the building foundations. There shall be a minimum clearance of 2.1 metres between the foundation and the soak pit to minimize the chances of dampness and slope failures due to seepage from the soak pit.
