The relationship between turbidity, residual chlorine concentration and microbial quality of drinking water in rural areas of Kashan during 2008-9

Common belief is that water quality evaluation must be based on its appearance, not only the apparent characteristics but also the microbial and chemical characteristics should be considered. This study was conducted to examine the relationship between turbidity, residual chlorine concentration and microbial quality of water used for drinking in rural areas of Kashan. This cross-sectional descriptive study was carried out on drinking water samples taken from 57 villages of Kashan during 2008-9. Among the total samples taken during three stages, only one sample was selected and analyzed for water quality parameters of turbidity, residual chlorine concentration and heterotrophic plate count (HPC). HPC, residual chlorine concentration and turbidity of water samples desirable in three stages and undesirable in another three stages were 86%, 22.8% and 75.4%; 12.3%, 29.8% and 0%, respectively. Furthermore, HPC in 95% of samples under the supervision of rural water and wastewater company (RWWC) and in 64.7% of samples that were not under the supervision of RWWC, were in the range of standard drinking water. The results of the study show that correlation between residual chlorine concentration and HPC level of drinking water in Kashan rural areas was significant, while there is no significant correlation between residual chlorine concentration and turbidity; HPC and turbidity. Hence, RWWC supervision has a prominent role in supplying safe drinking water for such areas.