In this study, after the pulse shape calibration of a liquid scintillation counting (LSC) spectrometer (Quantulus 1220), the effi ciency was determined depending on sample quenching parameters. Then, gross alpha and beta activities in two spiked water samples obtained from International Atomic Energy Agency (IAEA) were used for the validation of the ASTM D7283-06 method, which is a standard test method for alpha and beta activity in water by LSC. Later, the drinking water samples (35 tap water and 9 bottled water) obtained from different districts of Ankara, Turkey, were measured. The maximum gross alpha activities are measured to be 0.08 Bq/L for tap waters and 0.13 Bq/L for bottled waters, whereas the maximum gross beta activities are found to be 0.18 Bq/L for tap waters and 0.16 Bq/L for bottled waters. These results indicate that these drinking water samples are below the required limits, which are 0.1 Bq/L for alpha emitting radionuclides and 1 Bq/L for beta emitting radionuclides. As a result, gross alpha and beta activities in drinking water of Ankara were determined accurately by this validated LSC method. It is also worth noting that LSC is a rapid and accurate method for the determination of gross alpha and beta activities without requiring a tedious sample preparation.