Frequently Asked Questions

Rainwater Tanks FAQs by Tank Star

Rainwater tanks store rainwater run-off from catchment areas like your roof. In most cases, the water from your roof is funelled along your gutters and into downpipes connected to your tank. If you are going to install a rainwater tank, you may need to alter your guttering. To get the best out of your rainwater tank, it's important to install appropriate screens to stop debris and insects entering the tank.

What can I use my rainwater tanks for

Tank Star - Rainwater Storage Solution In urban areas, NSW Health supports the use of rainwater tanks for non-drinking uses, including:
  • Toilet Flushing
  • Washing Clothes
  • Water Heating Systems
  • Garden Watering
  • Car Washing
  • Filling Swimming Pools
  • Spas and Ornamental Ponds
  • Fire Fighting

NSW Health recommends that people use the public water supply for drinking and cooking because it is filtered, disinfected and generally fluoridated.

Irrigation Systems

Rainwater from your tank is suitable for use with garden irrigation systems. However, if you plan to connect your rainwater tank to an irrigation system, you should ensure that you have a filter on your tank. Algae or debris can sometimes be present in rainwater tanks, and a filter will stop blockages occurring in your irrigation sprays.

Toilets and Washing Machines

Connecting your tank to your toilet cistern or your washing machine is a good way to maximise the use of rainwater because you will use tank water even when it is raining. To supply your toilet and washing machine with rainwater you will need to maintain a minimum operating water level in the tank when there is insufficient rainfall. A licensed plumber should install a top-up system from the drinking water supply or a 'rainwater tank control valve' that automatically switches to mains water when the tank is empty. You will need to consult a licensed plumber about this.

Hot Water

Where rainwater is used in hot water systems it is particularly important that you are aware of the advice from NSW Health and the manufacturers of items forming part of or connected to the heated water system. Water quality can have a significant effect on the performance and life of water heaters and other items connected to the heated water system.

Hot water storage tanks have a device called a sacrificial anode which protects the hot water tank from corrosion. Although it is not common, it is possible that the mixture of rainwater and mains water will cause the sacrificial anode to wear out faster than normal. It is advisable to have the sacrificial anode in your hot water system checked or replaced every four to five years.

Planning for a Tank

Planning for a tank Before you buy a rainwater tank, it's important to plan ahead so you end up with a tank that best suits your needs.

Things to consider:

Use the checklist below to guide you when you talk to your tank supplier or plumber.
  • Size and type of tank to suit your needs.
  • Available area to locate the tank.
  • Size of the roof catchment area connected to the rainwater tank.
  • Extras like a pressure pump, ability to top up with drinking water, a backflow prevention device and a first flush device.
  • The suitability of your roofing materials.
  • Your budget.
  • What's involved in installation?
  • What kind of maintenance is necessary?
  • Council requirements.
  • Sydney Water regulations.
  • Check if you qualify for the Rainwater Tank Rebate Program.

If you have a garden and also need advice about rainwater tanks, why not register for Love Your Garden. This service provides expert advice on your garden's exact watering needs, and can give you information about rainwater tanks.


Apart from purchasing a tank, there are a number of other possible expenses you need to be aware of including:
  • Delivery
  • installation
  • Gutter, Roof and Downpipe alterations
  • A foundation or tank stand for above ground tanks
  • Excavation work for below ground tanks
  • Backflow prevention devices
  • A flow regulator
  • First Flush Device, Screens and Gutter Guards
  • Extra Plumbing
  • Maintenance
  • A Pump
  • A Pipe to Top up

Value for money and the environment

After weighing up the cost of a rainwater tank and its associated expenses, you should also consider the long term benefits of purchasing a rainwater tank. This includes the savings in your water use charges. Just as importantly, you should also consider that by saving water, you are also helping secure our water supply.

Maintaining a Water Tank

Maintaining a Water Tank It's important to maintain your rainwater tank and components so they work effectively and reduce the risk of contamination. Preventing problems before they arise will save you time, money and water.

Roofs and gutters

Gutters and roof catchment areas should be regularly inspected and kept clean and clear of leaves and debris. Any overhanging branches should be removed. It's a good idea to use screens or guards, which should be regularly cleaned. Keeping your rainwater screened and flowing cleanly and quickly from your catchment area into your tank reduces the build up of sludge as well as the risk of mosquitoes breeding in your tank.


Check your tank for sludge at least every two to three years. If sludge is covering the bottom of your tank, you'll need to remove it by siphoning it out or completely emptying your tank (contact a professional tank cleaner if you're unsure). Excessive sludge build up is a sign of inadequate roof and gutter maintenance.

First Flush Device, Screens and Gutter Guards

It's a good idea to install appropriate screens and guards to stop debris and insects entering the tank. Installing a first flush device is essential to reduce the amount of sediment and other materials entering the tank and polluting the water. Screens and gutter guards offer further protection by stopping insects and debris entering and breeding in the tank.

When do I need council approval to install a tank?

When installing a rainwater tank you should refer to the following State Environmental Planning Policy and also contact your local council to find out whether you will need council approval before installing a rainwater tank or tanks on your property.


Rainwater Tank Checklist

Rainwater Tank Checklist If you are considering purchasing a rainwater tank, we recommend installing a complete system to improve water quality and reduce tank maintenance. With a little planning, you can design and install a system that will not only give you good quality water, but will reduce your reliance on mains water. Rainwater that is captured and stored correctly is a safe, economical and sustainable source of quality water that can supply your complete requirements.

  • Check ROOF SURFACE is suitable for collecting quality rainwater.
  • Install GUTTER MESH to prevent leaves and debris from blocking gutters.
  • Fit GUTTER OUTLETS from the underside of the gutter to prevent obstruction of water flow.
  • Fit Leaf Eater or Leaf Beater RAIN HEADS to downpipes to stop gutters blocking. Rain heads deflect leaves and debris & keep mosquitoes out of pipes that hold water (for 'wet' systems).
  • Install WATER DIVERTER'S to prevent the first flush of most contaminated rainwater from entering the tank.
  • Ensure the TANK SCREEN is installed at tank entry point to filter water and keep mosquitoes and pests out.
  • Choose a WATER TANK. Consider annual rainfall, roof catchment area and water usage when determining its size.
  • Attach INSECT PROOF SCREENS or FLAP VALVES to the end of all pipes to the tank screen (for wet systems) and to TANK OVERFLOW OUTLETS to keep mosquitoes and pests out and ensure tank is vented properly.
  • Utilize a TANK TOP UP system (if required) to automatically top-up the tank with mains water when water levels fall to a designated minimum level.
  • Select a PUMP SYSTEM (if required) to distribute water for use inside or outside the home.
  • RAINWATER FILTER. Fit a purpose designed rainwater filter after the pump to help reduce residual sediment, colour and odour.
  • WATER LEVEL MONITOR. Install a level indicator to help monitor your water usage. Wireless systems are most convenient and display a reading inside the home.

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