Section 51(2) in West Bengal Municipal (Building) Rules, 2007
(2)Sewer and its appurtenances, underground water reservoir, septic tank and ramp may be allowed to be constructed in the open spaces up to 60 cm above ground level provided that these do not obstruct vehicular movement.A canopy or canopies and/or a porch or porches each not exceeding 15 squares metres in area or one percent (1%) of the ground floor area whichever is higher, having a clear width of not less than 2.5 metres may be allowed at a minimum clear height of 2.5 metres from the ground level;Provided that requisite space for the movement of fire tender is left all round the building unobstructed by such canopies or porches.
