Systematic studies on carbon-14 dating of tufa profiles in southern Poland have resulted in developing a simple phenomenological model which enables us to estimate the reservoir correction factor of carbon-14 dates of individual carbonate samples. Further studies to test model assumptions and to verify relationships between the value of reservoir correction factor T_R and ¹³C content of tufa carbonate were made. Rudawa and Szklarka, southern Poland, chosen as two new study sites, are close to previously studied sites. Some four tufa samples with associated organic fraction from ca. 2,000 m above sea level in the Peruvian Andes, South America were measured to test the possible application of the model to tufas in different geochemical and climatic environments. Finally, a series of calcareous tufa samples from the Villers-devant-Orval profile, Belgium, were dated, although no direct comparison with organic matter dates is available for this profile.