  The aim of this study is to investigate the presence of potential aquifer
layers that would be used as a source of clean water for residents in Cilongok
sub-district. We conducted a ground water potential survey at two locations in
the sub-district, i.e. Cikidang and Kalisari villages. At each location,
geoelectric measurements were taken with the Wenner configuration and the
horizontal distance of 900 meters, so that we can get the estimation of
lithology layers that potentially store groundwater up to the depth of $\pm
100$ meters. Then the measurement result was processed by using Res2DInv
software to get the 2D resistivity images of rock layers. Based on the
resistivity estimation and observation of regional geological conditions in
that area, then we conducted 2D interpretation about potential lithology layers
that economically potential for water well drilling and to be utilized as a
source of clean water for the residents. Based on the interpretation of
lithology, it was known that the aquifer layer that has the potential as a
source of clean water is a layer that consists of coarse and porous tuffs from
volcanic eruption products that can easily drain groundwater on the average
about 28 to 45 meters depth in Cikidang village and about 45 to 60 meters depth
in Kalisari village.
