A method has been proposed for determining a unique storage coefficient value for confined and unconfined aquifers tapped by a large diameter well. The prerequisites for the application of this method are estimation of the transmissivity value and the field measurements of well radius, pumping discharge and time-drawdown measurements at large times, or preferably at the steady or quasi-steady state flow conditions. The application of the method does not require any complicated mathematical procedure of the classical type curve matching procedures. It is recommended especially as a supplementary method to the existing techniques in determining the storage coefficient.