Introduction: Drinking water should be free of any chemical contaminants. One of the important aspects of drinking water pollution is presence of heavy metals that can be hazardous for consumer’s health. This study was carried out to determine the concentration of heavy metals in urban and rural drinking water networks of Hamadan province in 2016. Materials and Methods: This study was a descriptive cross-sectional study. In order to investigate the concentration of heavy metals in drinking water resources of the province, a total of 60 samples (38 rural and 22 urban samples) from water distribution networks was taken based on standard methods. After transferring the samples to the laboratory, the elements were measured by polarography and the results were analyzed using Excel software. Results: The heavy metals average concentration of Hg, As, Cr (total), Cu, Pb, Cd and Zn in all samples was 0.565, 6.733, 2.045, 11.637, 2.636, 0.031 and 282.596 µg.L-1 respectively. Only 1.67% of samples were contaminated with mercury, 3.33% were contaminated with lead and 8.33% samples were contaminated with arsenic. Conclusion: The results showed that the average concentration of heavy metals measured in all samples of Hamadan province was lower than the maximum allowed in the national and international standards. Apart from the worrying situation of arsenic amount in samples of a small number of villages, it can be concluded that the status of drinking water sources in terms of heavy metals contamination is favorable in Hamadan province, but annually control of arsenic is strongly recommended.