3. How much water does a family need per day? — The Norms

The National Building Code (NBC) as well as the Indian Standards (IS-1172)  state that a person  requires 135 liters of  water per  day ( about 9 buckets) for hygienic living. The NBC reckons a family to be made up of 5 members on an average. Of this total requirement of 135 ltrs.*, the quantum needed for cooking and drinking purposes is only about 10 -15 ltrs.; a substantial portion (about 40-45 ltrs) goes for flushing the water closets. The rest goes for bathing (30 ltrs), washing of clothes (15-20 ltrs) washing of vessels (10 - 15 ltrs) washing of floors ( 5 ltrs) etc. *This has been altered to 200 ltrs. for residential consumers in the latest revisions of both, whereas for all other consumers (Factories, Offices, Schools, Hostels, etc), the quantum has been retained at 135 ltrs. The selective upward revision for residential consumers alone from 135 ltrs. to 200 ltrs. without any explanation as well as the language used perhaps indicate that the revision is provisional. Our own extensive studies in a 24 apartment complex over 6 months have validated the adequacy of 135 ltrs. per head for essential needs. Our studies have also shown that 200 ltrs. per head takes care of all other needs as well, such as watering of plants, washing of vehicles and cleaning of driveways and staircases.