Corporation water in any city goes through some primary purification before being released to the local water pipeline. Not all corporations, however, follow an adequate purification process. Are you sure that the water treatment plant run by your city corporation follows all the recommended standards to make unpure water usable? Moreover,

About 60% of the Indian population still lives in village areas where the municipal water pipeline is not available. In urban Bharat, city corporations do not provide drinking water to all citizens of their serving area. Apparently, Borewell water is still the principal source of the drinking water in India,