The present chapter will focus on the water use in agricultural activity, under Mediterranean edaphoclimatic conditions, with very particular characteristics, such as climatic irregularity, the absence of precipitation in the summer months, and, in many years, much rainfall in the winter months, that can require the installation of drainage systems. Despite these climatic adversities, these climatic conditions are very good, many times the best conditions, for some crops, like olives, tomatoes, grapes, dry fruits, some vegetables, and others less important (Neira et al, 2024). Considering the importance of water in these climatic conditions, this chapter will look at three realities in three different countries in the Mediterranean basin, Portugal, Spain, and Italy, which highlight the importance of using water to obtain qualified agricultural production and high yields for farmers (Zagaria et al, 2023). In addition, climate change is altering precipitation patterns, leading to longer and more frequent droughts, as well as flooding during short periods (CanatárioDuarte et al, 2022). Overexploitation of aquifers and contamination of water sources has led to a reduction in the availability of freshwater, raising serious concerns for agricultural production (Rojas-Downing et al, 2017). The Mediterranean region is known for its agricultural diversity, where the production of crops such as olives, grapes, citrus fruits, and vegetables is essential for the local economy and the culture of the countries that comprise it. However, this region also faces significant challenges related to climate change, which affect water availability and, consequently, agricultural production. Agriculture is a key component of food security, which refers to access to sufficient, safe, and nutritious food to meet the dietary needs of a population. As the global population and food demand continue to grow, more intensive agricultural production approaches are required, especially in the Mediterranean region, where agriculture is vital for local economies. In a context where the population continues to grow, efficient water management becomes crucial to ensure food security and the sustainability of agriculture in the Mediterranean basin (FAO, 2020). Water is a vital resource, not only for crop growth but also for the livelihood of rural communities that depend on agriculture as their main source of income. Also, water is fundamental for photosynthesis, nutrient transport, and temperature regulation in plants (World Bank, 2016).