Check your rainwater tank to avoid issues in spring

With the season of spring not all that far away it may be time to have a look at your rainwater tank.

While the winter months bring cooler weather, lowering the likelihood of algae and bacteria to bloom, your tank and plumbing may be looking worse for wear.

Big or small, all gardeners are urged to maintain their rainwater tanks this spring to ensure all contaminants have been removed before use. Photo: Shutterstock.

Big or small, all gardeners are urged to maintain their rainwater tanks this spring to ensure all contaminants have been removed before use. Photo: Shutterstock.

Installing a water tank is not always a set-and-forget exercise with prudent tank management and continued maintenance ensuring you and anyone else who may come into contact with the water will remain happy and healthy.

Well-designed systems are low maintenance and in most cases roof catchments, guttering, piping and rainwater tanks are relatively simple systems and will need little attention.

All water storage needs to be protected from microbes and mosquito larvae.

Above-ground tanks can be likely sources of enteric pathogens including droppings deposited by birds, lizards, mice, rats, possums and other animals; or the presence of dead animals and insects, either in gutters or in the tank itself.

Reassuringly, except for people with severely compromised immune systems, these organisms do not pose a significant risk through normal drinking water, according to the World Health Organisation.

However, it is advised to install a first flush device and monitor it after rain. One complication can be the installation of buried or below surface pipework, which will require extra attention.

Buried pipework (so called 'wet systems') are used to maximise yields from multiple gutters and where rainwater is plumbed into homes.

However, buried pipes can be susceptible to cross-connection and external contamination as well as stagnation.

Spray drift from pesticides has long been thought to cause concern, however, in government surveys of rainwater quality in rural areas, most samples did not contain detectable concentrations of pesticides.

Other potential contaminants include Legionella, salmonella, bushfires, combustion heaters and potentially toxic roofing materials such as lead, asbestos, preservative-treated wood, cement-based or terracotta tiles.

Roofs used to collect rainwater for drinking should not include uncoated lead flashing.

Asbestos roofing material should be left undisturbed since fibres can be released into the air by actions such as cutting, grinding or drilling, and therefore cause harm.

Tank users are advised to prune overhead branches, cover inlets with mosquito-proof mesh, regularly clean gutters, disinfect tanks with chlorine if water is contaminated and the tank can't be emptied and cleaned, or simply boil water before use if needed.

  • Source: Federal government's Guidance on the use of Rainwater Tanks
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