Present Qanats are considered as enovmous investments in Iran, which have old history and great energy and much costs have been covered for them, Attention and protection for Qanats is necessary. In this study, we investigated Ahrestan Qanats water to analyze its quality condition (physical-chemical and microbial) and compare it with standards.For this purpose, sampling was done from 5 station along this Qanat in 4 stages, every month. Different tests were performed on these samples and the results were set in some tables. Results in station one showed that, turbidity, TDS, TSS, electrical conductivity, total hardness, chloride, sulfate, alkalinity in Ahrestan Qanat water were 1FTU, 7.25mg/L, 2368.8mg/L, 2378.8ms/cm, 563: 7mg/LCaCO3, 391.08mg/LCL-, 61.25mg/LSO4 , 268 mg/LCaCO3 respectively.Results in the last station showed that these parameters were 4FTU, 3.75mg/L, 654.3mg/L, 1278ms/cm, 379.35mg/LCaCO3, 189.44mg/LCL-, 35.5mg/LSO4, 167mg/LCaCO3 respectively. According to the results and by comparing them with related standards we can use this water for other consumptions, for example, for fish breeding consumption by animals, drinking (after filtration and chlorination), watermills, for tourism industry as well as in agriculture.