Rainwater tanks

Installing a rainwater tank is a great way to collect water for use in and around your home. Rainwater tanks come in all shapes and sizes and can be fitted to homes, businesses, schools, community centres and a whole range of other buildings.

Rainwater tanks can either be fitted for outdoor or indoor use. Externally connected rainwater tanks can be used to water the garden, fill the pool or to wash the car and boat. Internally connected tanks can be used to fill your washing machine and flush toilets.

A rainwater tank will help you save money on your water bills and will save our precious water supply for drinking. Collecting rainwater also helps the environment by limiting the spread of pollutants carried in stormwater run off.

Save our drinking water and collect 18,000 buckets of water a year.

Water savings

For every millimetre of rain that falls, a square metre of your roof will collect one litre of water. This means an average sized, three bedroom, single storey home could collect up to 180,000 litres of rainwater every year. This is a massive 18,000 buckets of water a year!

Choosing a rainwater tank

The size of rainwater tank required for your home depends on a number of factors, including:

  • How big is your roof?
  • How much rainfall do you get in your area?
  • How much space do you have for a tank?
  • How much water will you need for your garden? What type and size is you garden?
  • How much water does your household use? How many people live with you and what are their water use habits?
  • If the tank is your only source of water, what size do you need to avoid your tank running dry?

Installing a rainwater tank - Council regulations

When installing a rainwater tank you must follow the requirements set out in:

  • the State Environmental Planning Policy (Exempt and Complying Development Codes) 2008 or State Environmental Planning Policy (SEPP) 4
  • the National Plumbing and Drainage Code of Practice (AS3500)
  • the NSW Code of Practice for Plumbing & Drainage
  • Councils guidelines for installing a rainwater tank.

Below is a quick summary of some of the main installation requirements.

Council development applications

Rainwater tanks with a capacity of more than 10,000 litres (or multiple tanks with a combined capacity of more than 10,000 litres) require you to lodge a development application with your local Council.


To avoid the need for a development application, rainwater tanks should:

  • have a maximum height of three metres
  • be placed behind the front building alignment (and side alignment for corner blocks)
  • not be placed in front of the property
  • be located at least 450 millimetres from any property boundary in urban areas.

Rainwater tank covers

All rainwater tanks should have a tight-fitting cover so animals cannot gain access, as well as keeping it safe for children. Covers also ensure that water is not lost through evaporation and light does not enter and contribute to algae growth.

Top-up or bypass

Top up or bypass connections are required for rainwater tanks that are connected internally and installed by a licensed plumber. These link to the drinking water supply system to ensure your washing machine and toilet maintain minimum water levels and operate properly during low rainfall.

Backflow prevention

New water meters featuring a backflow prevention device may need to be fitted to your property. This will help ensure that water from your rainwater tank does not flow back into the drinking water supply system. If required, these new meters will be installed by your local Council at no cost to you.

All underground rainwater tanks require additional backflow devices which must be approved by your Council’s plumbing inspector.


Signs should be placed on your rainwater tank to clearly state the water is ‘Not for Drinking’ (as recommended by NSW Health).

Signs should be placed at the front of your property clearly showing that you are using water from a rainwater tank. A sign will be provided when your rainwater tank is inspected by Council.

First flush devices

First flush devices are required to be installed. These devices help reduce the amount of debris collected from your roof that builds up in your rainwater tank and also reduce the amount of maintenance required to keep your rainwater tank clean.

Maintaining your rainwater tank

The key to maintaining good water quality in your rainwater tank is proper maintenance. It is important to clean and maintain your rainwater tank regularly, particularly before heavy rain is expected. You can find out your rainwater tank’s specific requirements from your supplier.

Most rainwater tanks require you to:

  • regularly clean your roof, gutters, first flush devices and insect screens to remove leaves, sticks and overhanging branches
  • regularly check for mosquitoes and if they are present find out how they entered the tank and block their access
  • check the bottom and sides of the tank for sludge every two years. If sludge is present, you will need to have your tank cleaned or emptied.

Sediment in the rainwater tank may block your irrigation system or discolour your toilet cistern and washing machine. Professional rainwater tank cleaners can be found in the Yellow Pages.

More information about maintaining your rainwater tank is available in the NSW Health Rainwater Tank Brochure. For a copy visit http://www.health.nsw.gov.au/environment/water/Pages/rainwater.aspx The local Public Health Unit can also provide information on water quality and health. Phone 4320 9730.

Rainwater tank testing

Generally, your rainwater tank water supply shouldn’t need to be tested if it is well managed and maintained. However, if you do need your water to be tested many analytical and pathology laboratories can provide this service.They can provide sampling containers, complete water quality tests and provide results and recommendations.