This diploma thesis is focused on assessement of the minimum night flow in the water supply system. The first part of the work is focused on the research of foreign and Czech literature in the area of evaluation of water losses in water systems, evaluation and measurement of minimum night flow and comparison of values of individual indicators in the Czech Republic. In the practical part of the thesis, the minimum night flow is estimated and the water losses indicators are determined for selected DMA of Vsetin´s watter supply system, which is operated by VaK Vsetin, a.s.

This diploma thesis deals with the analysis of the time series of drains from the water reservoir and evaluation of the minimum night flow in the water supply network of the town of Valašské Meziříčí. In the theoretical part of this thesis were elaborated research of Czech and foreign literature focusing on drinking water consumption analysis, measurement and evaluation of minimum night flow and methods of determination of water losses in distribution systems. The practical part includes analysis of water outflows from reservoirs, evaluation of minimum night flow and determination of basic water loss indicators for selected district metered areas of the network. The above-mentioned water supply network is operated by the Vak Vsetín, a.s.