This chapter analyses soil–water microscale interactions through an analysis, which can underly larger-scale issues such as drought, irrigation, infiltration, evaporation, or soil–plant relationships. The approach followed is somewhat focused on concepts of mass and energy transfer and fluid mechanics. The topics assessed in this analysis include soil water energy status evaluated by matric, pressure, and gravitational potentials concerning horizontal and vertical water flows in saturated and unsaturated soil control volumes. These fundamental concepts are first embedded in issues such as porosity, bulk density, volumetrics, and mass soil moisture. The incompressible fluid tubular flow and mass transfer principles, Darcy’s Law in saturated soil and the equilibrium between main pressure and gravitational potentials are critical for understanding the soil–water relationships at several scales. Secondary processes related  to water flow are hysteresis, capillarity, and water redistribution in the soil profile, which leads to field capacity and plant available water concept. In a nutshell, this chapter intends to deliver a set of empirical and technical concepts that can help readers delve into many soil-water topics.