Section 4A(4) in The Special Rules for the Mulit-storeyed and Public Buildings, 1974
(4)In addition to the percolation pits of 30 centimetres diameter to be provided at 3 metre interval, 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 rainwater from terrace and side open spaces etc., flow over this sloped surfaces and spread into the filter bed all around. Masonery dwarf walls of 5 to 7.5 centimetres or of suitable height depending upon the site condition shall be constructed, if necessary, at the entrance and exit gales 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.
