Rainwater tanks collect rainwater from your roof to be used in your garden or your home.

They help to reduce the amount of stormwater that flows from properties, which can improve water quality in local creeks and improve habitat for local animals and plants. They can also reduce the need for us to replace or install new water supply and stormwater infrastructure.

Maintenance

If you have a rainwater tank, you need to regularly maintain it to:

• make sure the water is clean
• protect the health of your family, the local community and the environment.

We recommend the following maintenance for a newly installed rainwater tank:

After every three months:

• check and clean the first flush device
• drain all roof water charged lines.

After every six months:

• inspect your gutters and roof for leaves and other debris
• clean tank inlets, insect-proof screens and leaf filters
• check inside the tank for mosquito larvae or signs of animals and birds getting in
• check the pipework and make sure all connections are secure.

 After every two to three years:

• check inside the tank for sediment. If sludge covers the bottom of the tank, we suggest you have it cleaned. You can clean it yourself or use a commercial tank cleaner. A commercial tank cleaner will vacuum the tank with minimal water wastage.

Simple ways to keep contaminants out of your rainwater tank include:

• keep your roof clear of large tree branches
• keep gutters and downpipes clear of leaves and debris
• make sure inlet and overflow screens are in place, in good condition and cleaned regularly
• check the tank and fittings regularly for leaks
• replace cartridges in water filters and replace chemicals or components in water treatment units strictly according to the manufacturer’s instructions
• avoid harsh cleaning products that may contaminate your rainwater
• if you need to clean your roof, disconnect the pipes that feed into the water tank first. Then clean your roof with a chlorine solution (half teaspoon of household bleach with 10 litres of water) to scrub away any debris. Please follow the safety instructions for any chemicals used. Be mindful that cleaning the roof with a bleach solution can make the roof slippery.

For more information, please see Tips for maintaining your rainwater tanks (PDF 208 KB).

Tank desludging

You should check your rainwater tank every two to three years for build up of sediment and sludge.

The best time to clean your tank is when the water level is very low. You can clean it yourself or use a commercial tank cleaner.

If you add town water to a dirty tank, it can cause odour, unpleasant taste and floating debris in the water. This happens because the sludge in the bottom of the tank is disturbed when the tank is refilled. It then mixes with the chlorine in the town water and causes unpleasant changes to your drinking water.

If you decide to refill the tank without cleaning it, any debris will settle down over time and the chlorine will evaporate in a few days. In the meantime, you can boil the water to improve the taste and to make it safe to drink.

Water filters

The water we supply in Logan meets the Australian Drinking Water guidelines. Once the water enters your rainwater tank, it becomes your responsibility to make sure your tank is clean.

If needed, you should boil or filter your drinking water. We recommend you filter or boil your water if it mixes with rainwater coming from the roof as bird droppings or other contaminants may be present.

Water filters and other treatment devices help to prevent contamination of your household water.

Filters can remove bad tastes and odours, eliminate harmful germs and remove some chemicals in the water.

Most filters will only do one or two of these jobs effectively.

There are many other types of treatment options besides filters, each with certain benefits. Ask about the different options before you purchase a treatment system.

Corrosion

Direct contact between different metals or run-off from one metal surface to another can cause corrosion or holes. Corrosion in rainwater tanks can be caused by:

• metal roofing
• roof accessories
• gutters
• screens
• piping
• steel rainwater tanks.

Mosquitoes

Mosquitoes breed if they get inside a tank (or any system where water does not drain from pipes, gutters and plumbing). Mosquitoes may carry diseases like Ross River fever and dengue fever.

These steps will help stop mosquitoes breeding in your rainwater tank:

• make sure there is no debris in the tank
• install guttering that stops water pooling
• make sure water does not pool on the lid of the tank
• cover all entry routes to the tank with mosquito-proof screens (such as inlet and overflow pipes).

Mosquito-proof screens should:

• have openings less than one square millimetre
• be made of stainless steel or aluminium
• be secure but removable for cleaning. In some systems, screens can be in a rainhead – in this case, first flush the device or underground filter pit.

If you find mosquito larvae inside the tank, add a small amount of liquid paraffin or edible kitchen oil to form a thin film on the surface of the water. This stops any hatched mosquitoes flying out. Then investigate how the mosquitoes got into the tank and seal off their entry.

Water carrier supply

If you have potable water delivered by a water carrier, the carrier is liable for the quality of the water.

Within the terms and conditions of our approval to potable water carriers, the water carrier is liable for any change in the water quality as a result of transport, storage, treatment or use of the potable water after they collect it from a delivery point.

If you are concerned about the quality of potable water delivered to you, please contact the water carrier who delivered your water.

More Information

For more information about rainwater tanks, please visit the QLD Health website.