A LCC Analysis of Rainwater Management Variants

The paper presents results of the Life Cycle Cost (LCC) analysis carried out for several variants of rainfall water management in a newly designed multi-family dwelling house. According to the LCC methodology, calculations were performed for the whole undertaking life cycle with both investment outlays and operation/maintenance costs taken into account. The LCC analysis was carried out, in particular, for a variant assuming that the rainwater collected from the roof will be entirely discharged to the sewage system. On the other hand, the second variant provided for replacement of traditional building roof with a green one. Facilities of that type, thanks to their retention properties, may delay runoff of rainwater and reduce the overall quantity of water discharged from roof surface and therefore can be classified as Sustainable Urban Drainage Systems. In the third case considered, rainwater is to be utilised in the building. It was assumed that precipitation water will be stored in a tank and used in the sanitary water supply system for flushing toilets, thus reducing the overall tap water purchase costs.