<p>A study of pH and alkalinity in thirty-nine groundwater locations in the semi-arid region of Central India was carried out with the objective of monitoring and controlling the groundwater pollution seasonally. The study area was Sidhi district bounded by Son river in North, Gopad river in the east, Banas river in the west and Kusmi forest in the south. Geologically, the entire Sidhi district is dissected into Vindhyan, Archean, Dharwar and Permian regions. The study revealed higher alkalinity in the area ranging beyond the standard permissible limit while pH of all locations was well within the permissible limits (8.5). Increased pH and alkalinity were reported in the monsoon. The prevailing hydrochemical processes are water-rock interaction, seepage, percolation and leaching in the Sidhi district.</p>