Over the course of service, reinforced concrete (RC) elements are subjected to both mechanical as well as environmental loadings. While the guidelinesto facilitate efficient design of RC elements to withstand mechanical loading are well developed, the provisions to ensure durable performance under the given exposure conditions are rather inadequate and are mostly prescriptive across various standards. This frequently causes RC components to prematurely lose their durability, especially for the unconventional instances of material, structural design, and service conditions. Therefore, it becomes essential to develop reliable design guidelines, accounting for all the pertinent influences, to ensure a robust performance of RC elements over the desired period of service. Though there are many agents and phenomena that retrench the service life of RC elements, the presence of moisture has been long identified as a prerequisite for most of the degradation processes to initiate. This paper presents a critical discussion on the various moisture transport mechanisms in concrete as well as the modelling approaches commonly implemented for their description under isothermal and non-isothermal conditions. The study also emphasizes the necessity of considering realistic exposure conditions for the simulation of moisture distribution in structural concrete to facilitate a reliable estimation of service life.