Thematic maps are important for understanding water and its dynamics: they provide an overview of the state of water and water infrastructure, and they also have an important warning role. In the process of water management, many maps are needed. In order to provide sufficient quality, consistency, timeliness and coverage of the areas, maps have to be managed in an integrated way. Therefore, we propose the introduction of a system of thematic maps for water management in the form of a web portal, which takes into account the requirements of both managers and the legislation on water and spatial information. The concept of the system provides content composition, principles that the system must meet, proposes the use of modern forms of maps and an economical establishment of the system by using a joint editorial design, printon-demand function and open source solutions. An extensive list of thematic maps was created after examining the assessment area and the requirements of the current legislation. The system of thematic maps for water management is an attempt to establish order when displaying spatial data related to water, and to encourage experts' participation in water management and to include the public in the process of acquiring and controlling spatial data.