Rainwater harvesting system in a multi-family building located in Poland

Rainwater harvesting, storage, and utilization systems are widely used in many countries in order to reduce tap water usage. In Poland rainwater is utilized in very limited manner despite the fact that potable water resources per capita are one of the lowest in Europe. There are many different ways of using rainwater within a household, public or any other building. It might be used for watering gardens, flushing toilets and due to its softness for cars and windows washing, and in washing machines. In this paper authors described rainwater utilization system for flushing toilets in a multi-family building located in Poland. In this type of building rainwater commonly does not fully cover the demand and during dryer periods needs to be supported by tap water, nevertheless, it generates noticeable savings on potable water. This paper presents economic and environmental aspects of using rainwater harvesting system in a multi-family building under conditions of Polish climate. Calculations of cost, types of systems and designing methods, including tank sizing are presented and discussed