Section 83(3)(i) in Assam Notified Urban Areas (Other than Guwahati) Building Rules, 2014
(i)each building shall have a separate downward pipeline to collect waste water from bath and wash basins and the collected waste water shall be treated adequately by organic or mechanical recycling and taken to a Settling tank for onward pumping to the exclusive overhead tank or to a separate collection unit of over head tank for exclusive use of toilet flushing through cisterns. The excess waste water not reused for toilet flushing shall be suitably connected to the rain water recharge structures for ground water recharge.