Maintaining Your Rainwater Tank

© Think Water

Setup Considerations

If you have just purchased a rainwater tank, the tank and system may need to be washed or flushed before use. You can check this with the supplier or manufacturer of your new tank.

Once installed, all access points, excluding the inlet and overflow, should be sealed to prevent contamination. This will also help to block light from entering the tank to retard algae growth. A mesh cover and strainer should be installed over the inlet to prevent debris and insects, particularly mosquitoes, from entering the tank. Covering the overflow with an insect-proof screen is also important.

Installing a first flush device is a good way of further improving the quality of the water in your tank. First flush devices prevent the first runoff from entering the tank after an extended period without rain. This minimises contaminants such as dust, bird droppings and other debris that may find their way into the tank from the catchment area.

Maintenance

So you now have a rainwater tank installed, what next? Water tanks need regular, ongoing maintenance to ensure the tank and the water held in it are clean. To avoid a situation where the water in you tank is unsuitable for use, we recommend undertaking maintenance during seasons of low rainfall before periods of high rainfall are expected.

Maintenance of your rainwater tank should include the following:

• Ensure the roof catchment is kept clean and gutters are cleared regularly (at least 2-3 times per year);
• Use screens/guards on tank inlets and clear these regularly;
• Prevent ponding in gutters as this water may provide a breeding ground for mosquitoes, washing eggs into your tank;
• Clearing any sludge by siphoning/vacuum or emptying the tank every 2-3 years at a minimum.

While it is normal for some sludge to accumulate at the bottom of a tank, excessive build up likely indicates inadequate maintenance of the catchment area. Preventing excessive build up is particularly important as it can damage your pump if it is drawn into the system.

If the water from your tank is discoloured, smells foul (has a bad odour) or tastes funny, your tank needs cleaning or disinfecting. You can disinfect the water in your tank by chlorination with swimming pool chlorine or using a product such as Davey Acquasafe. Other methods such as UV water treatment are also gaining popularity.