Aims: Groundwater, especially in comparison with surface water, is one of the most critical sources of water supplies in different parts of the world. Due to the increasing demand in various parts of agriculture, household, industry, etc., and also decreasing groundwater level in recent years in Hamadan province, it is necessary to estimate the carrying capacity of groundwater resources. Materials & Methods: In this article, seven factors, having greater impacts on the carrying capacity of the region, were selected based on experts’ views during the 2001–2011 period. Furthermore, fuzzy comprehensive evaluation method using different membership functions (MF) was used to estimate the carrying capacity of groundwater resources. Findings: By considering different numbers of MF, the results of this study pointed out that groundwater carrying capacity decreased throughout the 2001–2011 period. Moreover, by functions in comparison with other methods, the reduction level of groundwater resources is better observed. Hence, the process of recognition of reduction groundwater resources carrying capacity in Hamadan Province can be immediately done. Conclusion: As a consequence, governments can make some proper and quick decisions and effective strategies to compensate the reduction and save implementation cost and time.
