Model of Accumulation of Rainwater from Surface Runoff in a Tank for Use in Building

There are various rainwater accumulation systems suitable for any building. Rainwater harvesting systems can be integrated into the building’s design, using rooftops and downspouts to collect rainwater. When applying the simplified method of design of the storage tank, only the required water intake for the selected storage period is considered. The average amount of precipitation that falls on the catchment area and is subsequently diverted and retained in the storage tank is not considered. The main goal of the article is to demonstrate the need for individual processing of rainwater balance using multi-year reductions of consumption in an apartment building and then to estimate the tank size. The use of a detailed method to design the volume of the storage tank reflects its model virtual filling and consumption of water. The results show that the simplified method is advantageous to use for smaller objects, where the captured rainwater can be used for several activities. For larger objects, it is more advantageous to use a detailed design method with its features.