The insufficiency of water resources and the need for potable water constitute a major concern for many countries, especially Morocco, which has experienced a significant increase in water demand due to population growth, economic development, and climatic conditions. To address this issue, Morocco has initiated an ambitious program to establish seawater desalination plants using reverse osmosis technology in semi-arid areas.This study addresses the pressing concern of ensuring the reliability and quality of desalinated water in the Al Hoceima seawater desalination plant, a vital initiative by Morocco to combat water scarcity in semi-arid regions. Employing the Failure Modes, Effects, and Criticality Analysis (FMECA) method, a comprehensive analysis was conducted to identify potential malfunctions compromising water quality and process reliability. Failures were ranked in descending order of criticality, and cumulative criticality was calculated to prioritize improvement actions. The Pareto diagram generated from this analysis helped identify critical failures in the studied system that require prioritized improvement actions. Notably, it was observed that 80% of the criticality corresponded to half of the failures. Consequently, an improvement plan should be developed for 12 out of the 24 predetermined failure modes, focusing on those identified as most critical. Subsequently, an improvement plan was formulated, integrating short-term corrective actions such as optimizing cleaning protocols and medium to long-term preventive measures such as upgrading equipment and implementing redundancy systems. This study contributes novel insights into enhancing process reliability in seawater desalination plants, particularly in semi-arid regions like Morocco, by providing a systematic approach to identify and prioritize potential failures, ensuring the sustainable provision of potable water.