“…Studies show that systems of rainwater harvesting have been implemented in different regions such as Australia (Fewkes, 1999a;Marks et al, 2006), Brazil (Ghisi et al, 2009), China (Li & Gong, 2002;Yuan et al, 2003), Greece (Sazakli et al, 2007), India (Goel & Kumar, 2005;Pandey et al, 2006), Indonesia (Song et al, 2009), Iran (Fooladman & Sepaskhah, 2004), Ireland (Li et al, 2010), Jordan (Abdulla & Al-Shareef, 2009), Namibia (Sturm et al, 2009), Singapore (Appan, 1999), South Africa (Kahinda et al, 2007), Spain (Domènech & Saurí, 2011), Sweden (Villareal & Dixon, 2005), UK (Fewkes, 1999a), USA (Jones & Hunt, 2010), Taiwan (Chiu et al, 2009) and Zambia (Handia et al, 2003). One of the most important steps in planning a system for rainwater harvesting is a method for determining the optimal capacity of the rainwater tank.…”