Guidance on use of rainwater tanks

3. Managing rainwater quality – an ounce of prevention

Page last updated: March 2011

Health and aesthetic hazards for rainwater collected in tanks can be minimised by sensible management procedures.

With the possible exceptions of urban traffic emissions in very highly populated centres, and industrial emissions, these hazards are amenable to individual action. Some preventive measures are associated with design and installation, while others are associated with ongoing maintenance. Well-designed systems are low maintenance.

In most cases roof catchments, guttering, piping and rainwater tanks are relatively simple systems. Implementation of a low-key management approach will generally prevent problems occurring, so corrective action to restore water quality will be needed infrequently, if at all. One complication can be the installation of buried or below ground pipework which will require additional attention.

As discussed in the ADWG, a preventive risk management approach is the most effective way of ensuring safe, high quality drinking water. This applies to all types of water supply, including rainwater collected in domestic tanks. The ADWG include the Framework for Management of Drinking Water Quality. The Framework addresses four general areas, and while each is important for community-based supplies, the area of system analysis and management is of prime importance for owners of domestic rainwater tanks.

‘System analysis’ involves identifying and assessing the hazards that can compromise rainwater quality while ‘system management’ deals with applying preventive measures to minimise risks to health, supported by monitoring and, where necessary, corrective action. For domestic rainwater tanks, monitoring mainly takes the form of visual inspection. These issues will be discussed in the following sections.