The distribution of groundwater is not uniform throughout the country. The spatio-temporal variations in rainfall and regional/local differences in geology and geomorphology have led to uneven distribution of groundwater in different regions across the country. Unplanned and haphazard development of groundwater in some areas has further compounded the problem and has led to a sharp decline in groundwater levels. As a result, a large number of shallow wells have gone dry, resulting in a huge loss and shortage of drinking water in 20 to 25% of the habitation in the country. Similarly, along the coastal zones also the delicate balance between sea water and the groundwater has been disturbed leading to sea water intrusion into the fresh water aquifers causing irreparable damage and environmental degradation. Systematic estimation and budgeting of groundwater resource based on its spatiotemporal distribution, its allocation for meeting the competing demands for irrigation, industrial and domestic usage, and conjunctive use of surface and a groundwater resource are, therefore, pre-requisite for optimal utilization of available groundwater on a sustained basis.