Yarmouk basin is considered one of the important basin in Syria due to its economical contribution in the total national production of the country. Also water plays a vital role in this effective activity of the economical development, the purpose of this research is to study the pollution in the southwest area inYarmouk basin on three levels: chemical, chemi-toxical and the Bacteriological. The study was done on three different sites which are: the outlet of Almzereeb lake, Zeizoun spring, Daael Al-kadeem well. The results were as follows: The rates of the concentration of both the ammonium and BOD in Zeizoun spring and Al-mzereeb lake high, where they exceeded the allowed limits in the drinking water of Zeizoun spring. But they remained within the allowed rates in the irrigation stander of Al-mzereeb lake, while there wasn’t any remarkable rising for such ions in the well of Daael Al-kadeem.