A sensitive and accurate method for determination of 210 Pb and 212 Pb in drinking water samples was developed. In the method Pb was pre-concentrated as hydroxides, separated from alkaline earth elements as PbS precipitate, purified by an anion exchange resin chromatography column, precipitated as PbSO 4 for source preparation and counted by a low background β-counter. The procedure was checked with a reference material supplied by the IAEA, and the obtained data were in good agreement with the recommended values, showing the recommended procedure can provide reliable results. The minimum detectable activity of the method was 0.039 mBq L −1 for 210 Pb and 0.033 mBq L −1 for 212 Pb if a 48 liter of water sample was analyzed. Seventeen drinking water samples were analyzed with a Pb recovery of 88.8 ± 5.5%, and the typical activity concentration was in the range of 0.191-15.1 mBq L −1 for 210 Pb and of 1.12-5.77 mBq L −1 for 212 Pb.