Water storage and retention is one of the most important ecological and agricultural properties of soil, since soil is the main water source for most plants. The present chapter discusses different ways of defining, measuring and modelling soil water retention capability, which varies according to the physical features of the soil. A detailed case study is presented, demonstrating how territorial patterns of soil water retention can be mapped and analysed. Given the time- and labour-consuming nature of such methods, we also show how readily available soil data can be used to estimate the water retention characteristics of large areas such as catchments. Finally, we review the main types of water loss and factors affecting water retention, with consideration of evapotranspiration, runoff and various soil properties.