Plumbing Africa November 2017 | Page 37

HEALTH AND SANITATION 35 contractors, developers, regulators, as well as members from municipal, provincial, and national levels of government. Ongoing review The South African rainwater harvesting guidelines will be periodically reviewed. The purpose of the reviews is to incorporate into the guidelines all relevant new information from international and local sources as they become available. To be continued in future editions of Plumbing Africa. Rainwater harvesting’s nationwide adoption and implementation have been at a much slower pace. www.plumbingafrica.co.za Figure 1: Number of households using rainwater harvesting tanks as main water source in each of the nine provinces of South Africa (DWS, 2014). Figure 2: Typical water use in South African homes (DWAF, 2003). Overview The South African rainwater harvesting guidelines will be divided into the following information sets: • An overall introduction and discussion on domestic rainwater harvesting within the South African context. • The current existing enabling environment: legal framework and institutional arrangements, or their lack thereof. • The factors that can affect rainwater quality and suggestions on how these risk factors can be mitigated through appropriate design, installation of rainwater harvesting systems, and use of appropriate household water treatment. • The first point of contact for rainfall, the catchment area, and conveyance systems required to transfer the rainwater collected on the rooftops to the storage tanks. • The issues that must be considered when selecting, sizing, and installing a storage tank. It therefore provides guidance on how to optimise the tank size and maximise system collection efficiency. • A synopsis of the various components that comprise a dual system; guidance on how to assess and then mitigate the risks associated with cross-connection and backflow. • Guidance on the selection, installation, and management of the appropriate type of overflow-handling system. • Financial assessment. PA Water collection in rainwater harvesting tanks at a low-cost housing project in Kleinmond, Western Cape. November 2017 Volume 23 I Number 9