Rain water harvesting (RWH) and Artificial recharge techniques are low cost solutions to water crisis. In cities, due to increasing urbanization, rain water can be harvested and recharged to the ground water artificially. This paper presents a study of effectiveness of RWH in terms of change of trends in aquifer behaviour. Chennai, formally Madras, City, capital of Tamil Nadu State is selected as the study area since major RWH structures has taken constructed during 2001-2003 because of

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... nt legislation. Preliminary analyses of rainfall and groundwater levels were carried with respect to space and time to understand the trends. Water table contours were drawn using the Arc GIS.9.2 software. "Groundwater Estimation Committee (GEC)" rules of Government of India were used for estimation the change in storage during pre and post RWH periods, which are found to be 1.76 Mm3 & 32.77 Mm3 respectively. It is concluded that the implementation of RWH has improved the groundwater storage though the rainfall in the study area is decreased and the extraction is increased due to raise in population.