Gross a and gross beta activities of 30 different water samples collected from sea, lake, river and tap waters in Adana were determined. The instrumentation used to count the gross a and gross beta activities was an alpha/beta counter of the low background multiple detector type with 10 sample detectors (Berthold LB770). The average measurements were 0.0096 Bq/l, 0.086 Bq/l for gross alpha and gross beta, respectively in drinking water. The obtained results showed that, in general, natural activity concentrations of alpha and beta emitting radionuclides in drinking water samples did not exceed WHO and ITS recommendations. To evaluate the annual effective dose equivalent of ingestion of these waters, a conservative dosimetric calculation was carried out using dose conversion factor suggested by the USA-EPA. Average annual dose of equivalent was calculated 0.005 mSv year(-1). (C) 2010 Elsevier B.V. All rights reserved.