What are the design basis for the distribution of the building including all the uotlets , lighting , water heater , airconditons etc. by square meter or square ft.

No of toilets is by number of people/user in the building, and that depends on the type of the building as well.
Lighting is by the quality and adequate level of visibility for different kinds of tasks.
Water heater is by number of people and Litre of water used per day
Air conditioning is by the amount of fresh air intake that's needed for a certain size of room with certain heat gain.
All of these have national and/or international standards. For example, in Australia, the first one is in the Building Code, while the second one is in the Australian Standards.