The hydraulic conductivity (K-values) of the aquifer media in the saturated zone were obtained from the grain-size analysis of 294 soil samples from drilled borehole data in the GTK-Lähde database and from literature. Due to inadequate K-value data available for the whole of Finland, the median K-values of each soil type were then applied directly to the base sediment of the superficial deposit of Finland scales at 1:20 000 and in some areas at 1:200 000.