The diploma thesis deals with the problems of sanitation installation in a multifunctional building in Kunstat. The theoretical part focuses on the analysis of the topic, with emphasis on the water demand. The experimental part focuses on drinking water consumption in real objects. The thesis also focuses on possible solutions given specialization. The project solves the sanitation installation of the multifunctional building in the selected variant. It is a multi-storey building where are a guesthouse for short-term accommodation, café, public toilets, commercial space and a fitness center.