The DRASTIC model has established itself as a fundamental approach for assessing groundwater vulnerability to contamination in various hydrogeological contexts worldwide. This model employs a fixed-weight and rating system for its parameters and sub-parameters, originally determined through the Delphi technique. Recognizing the limitations inherent in the static nature of the included weightages, it is necessary to enhance the precision and relevance of localized groundwater vulnerability scenarios through DRASTIC assessment. This chapter presents a comprehensive examination of the integration of Multi-Criteria Decision Analysis (MCDA) techniques in optimizing the DRASTIC model’s parameter weights and ratings. The analysis delves into the comparative efficacy of various MCDA approaches, scrutinizing their methodological frameworks, theoretical foundations, and practical applications within the context of groundwater vulnerability assessments. Particular attention is given to the inherent advantages and drawbacks of each technique, as well as the specific optimization challenges associated with aligning model outputs to the nuanced hydrological and geological characteristics of distinct study areas. Furthermore, the findings underscore the importance of selecting MCDA techniques that are congruent with the unique data availability, spatial scale, and accuracy requirements of the target assessment region. The study emphasizes that the indiscriminate application of complex optimization methodologies may impose excessive burdens in terms of computational effort, resource allocation, and implementation costs, without necessarily yielding proportional improvements in model performance. Thus, a strategic and context-sensitive approach to MCDA selection is advocated, ensuring that optimization efforts are both efficient and aligned with the overarching objectives of groundwater vulnerability assessment.