Results of field research on hydraulic conductivity coefficient of aquitards are presented in the article. The field research has been carried out in specially made piezometers, situated at the Dębina water intake in Poznań. The piezometers were filtered in Quaternary tills and Tertiary clays. The determination of hydraulic conductivity coefficient was carried out using the PARAMEX method. The air in a sealed piezometer was compressed which caused water injection from the piezometer into the examined aquitards. Then the pressure in the piezometer was reduced by means of seal removal and the pace of water infow into the piezometer, ie the water leveI rise, was observed. Theoretical consideration enabIing hydraulic conductivity coefficient determination on the basis of water injection from the piezometer into the examined aquitards has been carried out. The hydraulic conductivity coefficient was determined on the basis of both water injection and free water leveI rise. Laboratory research on hydraulic conductivity coefficient for till and clay sampIes taken during boring holes for piezometers, using the flow-pump method, was carried out simultaneously. The results obtained during field research have been compared to those of laboratory research. The values ot hydraulic conductivity coefficient obtained on the basis of laboratory research were lower by one order of magnitude than the results of on-site research. It has been found that sample consolidation, essential for conducting the laboratory research, leads to sealing the microcrack system occurring in natural conditions. Field and laboratory research carried out using the proposed methodology permit determining the variability range of the examined aquitards' hydraulic conductivity coefficient. The upper limit of that range is equal to the transmissivity of the crack system; the transmissivity of the consolidated bodies constitutes the lower limit. In this sense laboratory and field research can complement each other, which can lead to experimental determination of the variability range of the examined aquitards' hydraulic conductivity coefficient.