Recent incidences of high arsenic exposure from drinking water and human suffering in SE Asia notably in Bengal Delta Plain (BDP, Bangladesh and adjoining parts of Eastern India) appear to be quite different from that of the global scenario. The study deals with groundwater quality and hydrogeochemistry in arsenic affected areas of BDP and demonstrates that there is a clear difference in deep and shallow groundwater quality as well as hydrochemistry particularly in terms of arsenic concentrations. The extent of arsenic contamination is not well defined, however, is believed to cover large parts of the BDP and is now spreading to the adjacent virgin deltaic plains. The spatial variability is considerable over both the vertical and horizontal profiles. The investigation suggests that geochemistry of the arsenic affected shallow aquifers are nearly alike and scale is largely depends on the local redox signatures. The groundwaters hydrochemistry show that the dissolved arsenic spans over four order of magnitude (< 3- 1059 mg/l) with varying concentrations of As (III)/(V) and the concentration of associate redox elements (Fe and Mn ) are also relatively high. Alkaline earth elements (Ca2+/Mg2+/Sr2+/ Ba2+) are also present. The relatively high presence of alkali metals also reflects relic seawater influences. Chemical characteristics of shallow and deep aquifers differ and the causes of this difference will be discussed. Mitigation options for water supplies are being considered as are sustainable solutions for water resource management.