The Moroccan coastline has been subjected exceptionally to the growth of urban agglomerations as well as to the negative effect of various industrial activities, together with the contributions of watersheds, wadis and streams that dump their sewage and the waste generated by cities and their periphery. Aim: First of all, we carry out an evaluation of the Physicochemical, bacteriological state of the bathing water sample of the beaches of Ain Sebaâ-Zenata through the search of the bacteriological and chemical contaminants in three sites by reinforcing them to the national norms and standards which govern the quality of the bathing water, on the other hand, we compare these results with those found before the inauguration of the anti-pollution station East of Greater Casablanca. Study Design: Study of the seawater quality of three swimming beaches. Place and Duration of Study: Seawater was collected on 15/04/2017 from 3 sites in the Ain Sebaa- Zenata (Douar Abdellah Belhaj Beach, El Nahla Beach, Zenata Beach) region of the city of Casablanca after the installation of the anti-pollution station. Methodology: Our job articulates on two axes: On the one hand, the study and the analysis of the physicochemical, bacteriological quality of the seawater after the installation of EST Casablanca anti-pollution station at the level of three sites (Douar Abdellah Belhaj Beach, El Nahla Beach, Zenata Beach). On the other hand, the comparison of these results with others already carried out before the development of this station via the same characteristics: Physico-chemical, bacteriological. Results: In the light of the acquired results, a correlation was pointed out between the Physicochemical and bacteriological examination in comparison with the standards in the three studied sites, which were previously recognized as heavily contaminated bathing areas before the installation of the station. It supports the conclusion that this anti-pollution system has a beneficial and advantageous effect and confirms its cleansing role. Conclusion: The current physico-chemical and bacteriological results of seawater in the Ain Sebaaa - Zenata region after the installation of the anti-pollution station show a significant improvement in the quality of this bathing area as well as the beneficial effect of this plant, which performs a very considerable purification function.