United Nations Sustainable Development Goal (SDG) ensures adequately accessible water and management for all. Due to the rapid increase in population and industries along the Ganga river, it is necessary to estimate the water budget for fulfilling the demand for water in the future. The M-K test conducted on the Noah-Land Surface Model data for 72 years results in maximum declining trend of water budget in the Yamuna Lower (Q=-3.82BCM/year), and minimum in the Damodar sub-basin (Q=-0.10BCM/year). All the sub-basins show increase in groundwater level (mbgl) except the Kali Sindh, which shows decreasing trend (Q=-0.07 m/year). The extreme severe groundwater drought were estimated using Standard Groundwater Level Index (SGWLI), of the values for the Ram Ganga Confluence (SGWLI=2.44;2005), Upper stream of Gomti (SGWLI=2.06;2014), Ghaghra (SGWLI=2.22;2005), Ram Ganga (SGWLI=2.28;2005), Yamuna Lower (SGWLI=2.13;2007), Kali Sindh (SGWLI=2.30,2.67;2002,2003), Chambal Upper (SGWLI=2.30,2.20;2001,2003), Son (SGWLI=2.02;2010), Gandak (SGWLI=2.37;2010),Kosi (SGWLI=2.08;2012), Damodar (SGWLI=2.72;2010), and Bhagirathi (SGWLI=2.06;2014) were obtained for a period of 1996 to 2016 using a total of 62,050 observed well data.The obtained in-situ point data are converted into the surface raster using geostatistical technique. Our results show declining trend in the water budget of all the 19 sub-basin of the Ganga basin, and also the groundwater drought in several parts. Policy makers will benefit from our findings as they can use them to further UN Sustainable Development Goals such as ending poverty (SDG-1), hunger eradication (SDG-2), clean water & sanitation (SDG-6), socioeconomic development (SDG-8) and climate action (SDG-13) all of which must be accomplished before 2030.