Geostatistical techniques are presented for estimating the areal distribution of specific conductance as an indicator of the degree and extent of ground-water pollution. Combinations of measurement types including surface geoelectrics and monitoring wells are evaluated in terms of the prediction error. A realistic example using several combinations of surface resistivity and borehole measurements of specific conductance is presented. Results of the example are analyzed and show the increase in prediction accuracy possible by combining the two measurement types.