摘要：Designing of sustainable water systems should be aimed at reducing the consumption of tap water and the use of alternative water sources, such as rainwater and graywater. Therefore, the aim of the researches conducted was to determine the cost-effectiveness of the economic exploitation of rainwater utilization system in single-family house. As a tool for the analysis, the methodology Life Cycle Cost was used. It provides a comparison of different investment options and the opportunity to choose the one that is characterized by the lowest costs over the entire period of exploitation of the object. The research was conducted for four installation variants: the traditional solution and a solution in which rainwater was used for flushing toilets, washing and watering the garden. Variable parameters for calculations applied in the model were, among other things, different number of occupants and different length of exploitation of the installations. Additionally, the study included co-financing for the initial investment, which could be an incentive for residents to undertake this type of installation. The analysis conducted has shown that the systems with the use of rainwater enable significant reductions in the consumption of drinking water, while the variant with the traditional system was a most cost-effective solution only in few cases.
