Section 7A(4) in Multi-Storeyed and Public Buildings Rules, 1973
(4)In addition to the percolation pits of 30 centimetres diameter to be provided at 3 metre intervals, a pit of 1 to 1.5 metres width and appropriate depth, so as to recharge the ground, shall be provided all along the plinth boundary depending upon the soil classification below ground. This pit shall be filled with appropriate filter material namely, broken bricks, pebbles, broken stones, etc., at the bottom and the top 15 to 25 centimetres shall be filled with coarse sand. The ground or pavement surface around the building shall be sloped towards the percolation pit so that the surplus rain-water from terrace and sides, open spaces, etc., flow over this sloped surfaces and spread into the filter bed all around. Masonry dwarf walls 5 to 7.5 centimetres or of suitable height depending upon the site conditions shall be constructed, if necessary, at the entrance and exit gates to allow the surplus rain-water collected within the compound to recharge the ground within the premises itself, and from draining out to the road.
