Cost analysis of a rainwater harvesting system in Poland

Abstract

Rainwater harvesting is an alternative water supply method that has become popular in recent years around the world. This is mainly due to financial reasons (reducing the cost of potable water and fees for rainwater discharge to the sewerage), but also because of environmental awareness. In Poland, rainwater harvesting systems are not often used because of their low financial viability determined by high system construction costs and the low prices of potable water. Earlier analysis conducted by the author showed that the payback period of investment outlays was from a dozen or so years for large buildings, to a few dozen for single-family houses. This situation may change after the introduction of common fees for discharging rainwater from impervious areas into sewerage, and fees for the reduction of natural retention on newly built-up areas, in accordance with new water regulations. This paper presents a cost analysis of rainwater harvesting systems for ten cities in Poland, with varying annual rainfall depth and various pricing for potable water. Analyses were carried out for a single-family house located in an area equipped with a municipal sewer system, and for a large building, located in an area equipped and not equipped with a municipal sewer system.