Recent investigations into the hydrogeology and water balance of the Padthaway irrigation basin have suggested that the current level of consumption of groundwater for irrigation purposes is very close to the safe yield and that any appreciable increase in groundwater consumption would lead to an increase in salinity throughout the basin. With the extension of the Underground Waters Preservation Act over the Southeast, including Padthaway, it has become necessary to critically examine applications for permits to drill additional bores. Because of this, it is desirable to have additional and more reliable data from which a more accurate and refined assessment of safe yield can be determined. It has been estimated by Harris (1971) that more than 80% of the recharge to the Padthaway basin occurs by the flow of groundwater from the Naracoorte Range into the irrigation area. It was therefore decided to carry out an aquifer test further back into the range than previous tests to gain a better idea of the hydrogeology of the range and to refine the recharge estimate. PAR 37, the bore at which the aquifer test was conducted, is one of a line of observation bores across the range, designed to examine the water table in cross section.