The study aimed at investigating water awareness level of Post Basic Education's Students in the Sultanate of Oman. To achieve the purpose of the study, the researcher developed water awareness measurement consisted of three components: knowledge test including 40 multiple questions distributed into five domains; attitudes scale including 15items distributed into three domains and behavior scale including 10 water consumption behaviors. The validity of the measurement was examined by a panel of judges (11) and the reliability was examined by applying it to (39) students and it was found reliable (0.72%) for knowledge test; (0.86) for attitudes scale and (0.74%) for behavior scale. The study sample consisted of 716 students from Muscat and Dakiliah provinces. The study results showed the following: - Post Basic Education's students achieved average level of water awareness with percentage mean (57%) for three components. They obtained 47% in knowledge component, 78.83% in attitudes component and 51.32% in behavior component. There were significant differences at level of ( 2,.5) in students' water awareness due to their province in favor to Dakiliah. - There were significant differences at level of ( 29.5) in students' water awareness due to their gender in favor to female in water level of awareness general mean and in knowledge component but no differences were found in the other two components. The study highly recommended finding out reasons behind such average level of water awareness of post education students because they represent the outcome of the recent developed education systems in Oman. It also recommended reviewing water information which is included in social studies textbooks in general and in geography textbooks in particular due to the water situation in Oman and the important of individual role in facing water crises.