Radium isotopes can be analyzed by different analytical methods based on gamma spectrometric measurements or alpha spectrometry. An improved method was developed to determine radium isotopes from water using gamma spectrometry after radiochemical separation. The Radium was selectively extracted from acidified samples using co-precipitation procedure with iron hydroxide and followed by precipitation of radium as radium sulphate Ba(Ra)SO₄. The precipitate Ba(Ra)SO₄ was filtered through the Millipore filter paper, dried and weighed to calculate chemical yield. ²²⁶Ra and ²²⁸Ra activities were measured using low-background gamma spectrometry in water samples. Radium was pre-concentrated from environmental samples by co-precipitation with BaSO₄. The amounts of ²²⁶Ra and ²²⁸Ra on the sample were obtained by gamma-ray spectrometry for the 351 keVγ-ray from ²¹⁴Pb and for the 911 keV γ-ray from ²²⁸Ac, both in radioactive equilibrium with precursors, respectively. The accuracy, selectivity, traceability, applicability and Minimum Detectable Activity (MDA) of the technique were discussed. Also, the effect of physical and chemical characteristics of the water samples such as TDS, pH, soluble species, sulphate and bicarbonate that effect on the radium determination were taking into consideration. The method has been validated with a certified reference material supplied by the International Atomic Energy Agency and reliable results were obtained. The radiochemical yields for radium were 70% - 90% and recovery was 97% and 80% for ²²⁶Ra and ²²⁸Ra, respectively.