Low voltage (LV) distribution networks mainly feed single-phase customers. Even if the end-users of a given LV network may have similar electrical behaviors, unbalances among the three-phase loading are extremely common. This issue is exacerbated by the appearance of new single-phase intensive and often coincident loads, such as the electric vehicles' residential charging stations. In this work, a methodology is proposed to evaluate the effects of residential charging on the quality of supply voltage of LV grids. Then, a decentralised approach is proposed, based on the multi-agent system technology, which allows the different flexibility resources available on the grid to act together to achieve a global goal. In the scenario analysed, the agents cooperate to regulate the network nodal voltage, taking into account the characteristics of the resources they are controlling and the needs of distributed energy resources' owners. A case study derived from a real portion of the Italian distribution system demonstrates the validity of the approach in solving the network operation criticalities (i. e., voltage regulation issues, line congestions, voltage unbalances, etc.).