Abstract: This study reports on the impact of Al-Bireh wastewater treatment plant beside the sources and types of potential pollutants and presents water quality data for Wadi Al-Qilt drainage basin. Surface water samples were collected over a study period from November 2004, through May 2005 from 13 sampling stations along Wadi Al Qilt and analyzed for physicochemical and hydro biological parameters. According to standard methods for the examination of water and wastewater chemical parameters (Ca+2, Mg+2, Na+, K+, HCO3¯, SO4-2, Cl¯, NO3¯, BOD5, COD, DOC, trace elements such as Ag, Al, Ba, Cd, Co, Cr, Cu, Fe, Li, Hg, Mn, Ni, Pb, Sr, Zn, Be, Se and Mo), physical parameters (pH, turbidity, TDS, EC), microbiological parameter (fecal or total coliform) and hydrobiological parameter (chlorophyll a) were analyzed. The flow measurements were carried out using current meter method. Results revealed major trends for most of measured parameters with decreasing tendencies in pollutants concentration down stream. Dilution factor caused by springs outflows and the self-purification processes within the Wadis bed might be behind the decrease tendencies. Three Wadi samples were trace metals contaminated (aluminum, cadmium and lead), while all water samples revealed microbiological contamination signs. The results obtained for physical, chemical and biological parameters showed that the most polluted section through Wadi Al-Qilt is the part between AWWTP and Wadi Sweanit, indicating pollution of water discharging from springs downstream.