The potential for sustainable rainwater management through domestic rainwater harvesting based on real rainfall

Rainwater harvesting systems (RWHs) are identified as an alternative technology that is important for sustainable stormwater management through reuse, conservation, and reduce runoff. In recent years there has been a growth of studies on the effectiveness of RWHs. However, analyses of the system performance based on the site specific conditions are still limited. The aim of the study was to assess of the potential for rainwater reuse (householder’s interest) and reduction of roof runoff by RWHs (an environment’s perspective) assumed in a single- family building. Two performance indicators have been calculated i.e. water saving potential (WSE) and overall efficiency (OE). Four realistic scenarios (S1–S4) and three main non-potable water requirements were defined. The results of the study showed that WSE and OE varied depending on the type and size of the tank, the economic purpose, and the amount and irregularity of precipitation. The potential for the use of water stored in above-ground tanks for plant watering ranged from 62 to 82%. Underground reservoirs, with a larger capacity, were able to cover water requirements for this purpose up to 100%. However, the OE of tanks receiving runoff from the entire roof area were at low levels. Values of OE ranged from 3.7 to 6.8%, from 5.5 to 9.2%, and from 42.9 to 71.0%, for above-ground (S1 and S2) and underground (S3) and (S4) tanks, respectively. The results of the study may be useful for planning domestic rainwater harvesting systems and for comparison with practices in other countries.