History and Objectives: Use of non-sanitary water may lead to various health problems. Stagnant water is a source of drinking water that is more susceptible to contamination. In the city of Kashan, in addition to the water piping system, there are many water reservoirs are filled with water brought from surrounding villages by tanks and studies on the microbial flora of water from these villages have shown various levels of contamination. Therefore, the present study was conducted in 1995 to determine the microbiological characteristics of coli-forms in these reservoirs.

Materials and Methods: In this descriptive study, 3 separate samples were obtained from each active reservoir in Kashan using a standardized method. Each sample was tested in 2 separate steps at the Environmental Health Laboratory of Kashan University of Medical Sciences by a health faculty member. In the first step, samples were studied to identify coli-forms using the three-tube method and the MPN was calculated. In step 2, fecal coli-form positive samples were determined, based on the World Health Organizations standard chart.

Results: Of the 35 active water reservoirs in Kashan, 8 reservoirs (22%) had standard drinking water and 8 (22.8%) were recognized to be completely unsafe. The remaining reservoirs (54.4%) had various levels of contamination.

Conclusion: Based on the findings of this research, we suggest further analytical studies be performed to identify the causative factors leading to the contamination of these reservoirs. In addition, we recommend that the 8 unsafe reservoirs be temporary shut down.