35 vertical electrical soundings were conducted to outline and define parameters of the freshwater basin situated 20 km west of Warooka on southern Yorke Peninsula. The basin is thought to extend beyond the surveyed area in the south but most of the useful aquifer (the portion containing the best quality water and highest storage coefficient) has probably been delineated. Geophysical evidence suggests that the basin is a limestone deposited in an old valley; the valley is evident now only in the south. The present valley in the northeast is a more recent feature formed after limestone deposition.