Caring for the Catchment : What you can do

Install a rainwater tank
Rainwater tanks have many advantages – no matter where you live. Even in urban areas where a mains water service is available, rainwater tanks can help conserve valuable drinking water and reduce runoff.

Rainwater tanks reduce the physical impact of stormwater on drainage infrastructure, roads, urban streams and beaches and mitigate flooding. They also contribute to reducing contaminants in our waterways. This can be achieved through detention, which holds stormwater temporarily in tanks, but allows it to slowly flow to the drainage system. Alternatively, it can involve retention, which holds rainwater for reuse on site.

Retention of rainwater allows for its reuse for outdoor use such as gardening and washing cars. When integrated with household plumbing and by using a pump, a rainwater tank can also supply water for other uses.

Reusing rainwater conserves drinking water thereby cutting costs for households, and commercial users, while reducing demand for potable water .

Many people who have rainwater tanks do not take full advantage of them, using them simply for drinking water.

If you are considering installing a rainwater tank investigate with your builder how it can be plumbed to enable the supply of water to such areas of your house as the bathroom and laundry. Consider also how it can be used to irrigate your garden. Naturally if you are looking at using your tank for a variety of purposes you will need to ensure that the tank you install will be large enough to capture and supply the quantity of water you need.

There are no restrictions on water supplied by a rainwater tank, but such a decision is undertaken at the risk and responsibility of the property owner. This is because, unlike mains water, the quality of rainwater cannot be guaranteed.

Here are a few tips on how you can minimise the risks from rainwater tank supplies.

• Install an effective strainer for keeping leaves, debris, animals and insects out of the tank intake and overflow – for example, a suitable wire mesh screen. A reputable tank manufacturer can advise on this. Some strainers are ‘self-cleaning’.
• Install a ‘first flush’ diversion device. These devices ensure that the first few litres of runoff, which is usually the poorest quality, bypasses your tank. A reputable tank manufacturer can also advise on this.
• Ensure the tank is light-proof (to prevent algae growth).
• For new homes, or after roof renovations, divert water away from the tank for the first few heavy storms.
• Check gutters, strainers and first flush devices at least every three months, or more if trees overhang. Keep them clean and free of leaves etc. Ensure the tank lid is tight.
• Check the tank every two years for sludge and clean the tank if there is a thick layer of sludge on the bottom of the tank. Contractors are available in some areas to desludge rainwater tanks. Note- with galvanised steel tanks, it is important when cleaning not to disturb the film that builds up on the inside walls of the tanks, as this protects the metal from corrosion. It is also important not to scour the protective internal polymer coating on tanks made with ‘aquaplate’.
• Boil water from the tank before drinking or cooking if the bacteriological quality of the water is in doubt.
• It is recommended that the infirm and immuno-compromised should not drink untreated rainwater
• Consider having your tank regularly cleaned by a reputable rainwater tank cleaner.

In periods of heavy rain, your rainwater tank may overflow. Take precautions to ensure that any overflow from your rainwater tank is dealt with in an appropriate manner.

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NOTE:
While every effort has been made by the Adelaide and Mt Lofty Ranges NRM Board to ensure the accuracy of the information provided in this guide, no guarantee is given, nor responsibility taken, by the Board for errors or omissions. The Board does not accept responsibility in respect of any information or advice given in relation to or as a consequence of anything contained here.