An analysis of surface water presence of one hundred most important towns of the Czech Republic has been conducted with respect to their proportion to town area. The results of the analysis, which was performed on the basis of data from specialised water management database, were visualised in a poster clearly showing 'blue areas' in given towns. In relation to the visualisation purpose, which was the comparison of towns, the towns were presented so that their area was identical. The order of towns in the poster was established in accordance with the representation of blue areas. As supplementary information, the total area of blue areas per capita was displayed in visual form. The poster is accompanied by a map showing the location of the towns within the Czech