Arsenic is widely distributed in nature. Various surveys have been conducted which have served to quantify levels of arsenic in different environments and have provided an understanding of the natural and the anthropogenic sources of arsenic concentration in drinking water. The main sources are mine pollution and by natural deposits like arsenopyrites. Obuasi, considering its geography has arsenopyrites occurring there naturally. Therefore, it is unknown as to how much arsenic occurs in their groundwater naturally and it is however not clear whether a groundwater source has been polluted from mining activities or by natural deposits. This can be solved by estimating a background concentration of the Arsenic in groundwater at Obuasi. Background concentration is the amount of naturally occurring chemical substances derived from natural processes in the environment as close as possible to natural conditions, exclusive of specific anthropogenic activities or sources.Therefore, background analyses are essential for distinguishing between groundwater that has been impacted by natural processes and groundwater that has been impacted by anthropogenic activities.