Water is an essential source to life and is important to understand that urban water management and its conservation play a critical role in enabling a sustainable urban environment. Having a secure supply of clean water to a town is of fundamental importance as it is known to all, the multi-interest utilization of water resources everywhere.

Thermal treatment is the main force for crystallization and phase transformation, the behavior of precursors on heating revels a lot of information about the possible phenomena of involving stability, sensitivity and some predictive ability of zeolites. Thermo-gravimetric (T.G.) in combination with differential thermal analysis (D.T.A.) changes in precursor samples including the structure collapse and phase transformation at high temperatures were checked by recording T.G./DTA plots of Highi silica H-US Y zeolites using SETERAM T.G.DTA-92 instrument in air atmosphere 0 30ml//min. at a heating rate of 5 c //min. the range of temperature studied 0 using this instrument is from room temperature (RT) to 1000 c . The selective samples are post Synthesized and are obtained from low silica Na-Y zeolite converted in to high silica USY zeolites, are studied in the present paper. The post synthetic modification of the original samples affects the pore dimension, crystalinity, void volume, frame work structure, catalytic activity, selectivity, stability etc of the original sample.