Deepak was a poor boy and his mother worked as a domestic servant in Raziya's house. Perhaps, he lives in a chawl, which is a 4 or 5 storey building with single-room flats. In such a place, there is a common tap for the whole society. Even through this tap, water flows only in the early mornings and in the evenings. Thus, people have to stand in a queue to collect water.
Raziya perhaps lives in a high-society building where water is available throughout the day because of some water conservation system. Such systems include water reservoirs, tanks etc. that supply water to the people of the society all day long.