This research aimed at determining the knowledge level of agricultural local opinion leaders concerning the damages of irrigation by untreated drainage water, and the suggestions of agricultural extension workers for controlling these practices. Three villages were selected randomly in sedy sallem district. A sample of 206 opinions local leaders were determined by key informants. Frequencies, percentages, arithmetic mean, and standard deviation were used for presenting results. The most important results could be summarized as follows: 1- (73%) of respondents used agricultural drainage water in the irrigation process, (18%) of them used mixed water and about (9 %) of them irrigated with fresh water. 2- The knowledge level of (79%) of the total respondents with damages of irrigation with drainage water was high. 3- The most important suggestion for controlling the damages resulting from using drainage water were as follows : conducting training workshops regarding the disadvantages of using drainage water, providing farmers with recommendations for correct irrigation and activating the role of agricultural extension.