Independent Residential Rainwater Harvesting Guide

Written by

September 24, 2017

Figure 1: Schematic of the rainwater treatment train

Independent rainwater guide for residential housing

This guideline is provided by  Urban Water Cycle Solutions (UWCS) and the Rainwater Harvesting Association of Australia (RHAA) for above ground rainwater harvesting systems connected to residential dwellings in urban areas. It applies to dual water supply, using rainwater from roof catchments and mains water supplies. Rainwater is used first, when stored rainwater is available, for a range of uses such as outdoor, toilet, laundry and hot water supply. When stored rainwater is not available, all household water demands are supplied with mains water. The household is also encouraged to choose the highest level of water efficiency.

Correctly installed rainwater harvesting systems develop a natural treatment train that addresses many of the potential contamination issues that may be associated with a roof catchment. This is an important reason why rainwater harvesting is so widely used in Australia and rainwater users remain healthy. Australian health data indicates drinking untreated rainwater provides health outcomes similar to mains water. One in four households use rainwater harvesting in Australia. The householder is responsible for the quality of all water sources (mains water and rainwater) in their house. Professor Peter Coombes and other independent scientists have extensively monitored residential rainwater harvesting systems. We used that data to inform this design specification. This evidence  is independent of the perspective of the traditional water industry and the centralized distribution paradigm.

This independent design specification is a living document that will be regularly updated in response to evidence, discussions and independent science. The user is encouraged to provide comments and feedback to this webpage for inclusion in the ongoing review process. We are in the process of publishing additional scientific publications that will provide a summary of the comprehensive review process that underpins this guideline.

The guideline can be downloaded here Rainwater Harvesting Guide. A high resolution version of the independent guideline is also available from Urban Water Cycle Solutions




Dr Peter Coombes

Dr Coombes has spent more than 30 years dedicated to the development of systems understanding of the urban, rural and natural water cycles with a view to finding optimum solutions for the sustainable use of ecosystem services, provision of infrastructure and urban planning.

Connect with Peter

Related Articles

Urban Flood Risks, Water Law and Insurance

Urban Flood Risks, Water Law and Insurance

Urban flood risks, water law and insurance: The intersection of emerging science, practice and authority  By Professor Peter J Coombes Published in Precedent issue 178 - September/October 2023, Journal of the Australian Lawyers Alliance This article discusses the...



Results from two decades of accumulated big data and systems analysis of Greater Melbourne and Sydney was investigated to develop insights into the resilience of each city. The key resilience parameters are distributed water sources and conservation in an urban water market, household welfare, government policy and regulation, pricing strategies, total dam storage and supply of desalinated water. These parameters have different levels of impact and significance across the two cities. Further studies are needed to better define the attributes and benefits of these parameters.