The aim of this study was the monitoring of estrogens along the Baliqlychay River as a drinking water source of Ardabil City in Iran, annually. Eight sites were selected and the effect of Nir City crude sewage and wastewater of two fish farms on the amount of hormones in Baliqlychay River and drinking water distribution network of Ardabil City were studied. Samples were tested for Estrone and 17β- estradiol using HPLC. It was found that there was no Estrone in the studied stations but all of them were polluted by 17β- estradiol. During the grazing season and entrance of contaminated crude sewage of Nir City, animal feces are the main source of 17β- estradiol pollution. The efficiency of the Ardabil wastewater treatment plant depends on the water consumption rate. In normal conditions, the wastewater treatment plant showed an acceptable performance and removed 58.82- 63.25% of E2. But, at high consumption seasons, hormone removal is negligible.