Water is a major source of economic development, social security and poverty reduction. The value of this resource on the one hand and its limitation on the other hand has led to increased management measures to maintain the quantity and quality of water by different communities. In this research, the water quality index (WQI) for the Dehroud and Tang Eram regions of Dashtestan in 2007 has been investigated. The average WQI in 2007 is 66,798. WQI was better off in the Northeast in 2007 than in the Southeast. The maximum values of PH, TDS and EC in 2007 are 7.9, 5000 and 7500, respectively.