Using rainwater

As Canberra grows bigger with new housing developments and roads, it is inevitable that the volume and frequency of stormwater runoff will increase, due to the introduction of more impervious surface areas (roofs and tarmac).

This is why rainwater tanks are so important. By collecting and redirecting rainwater from the roof to use in your home and garden, you can reduce demand on the ACT's drinking water supply. You can also reduce the amount of stormwater runoff that reaches our creeks and rivers, where it can cause downstream flooding and erosion.

For more information on the benefits of installing a rainwater tank, how to size a tank to suit your needs, how much rainwater different size tanks can harvest, installation and approval requirements and tank maintenance, see the ACT Government's Rainwater tank guidelines for residential properties in the ACT External Link (PDF 3.6 MB) .

Here are some frequently asked questions to help you when you are thinking about installing a rainwater tank.

How can I use rainwater?

The simplest arrangement for a rainwater tank is to connect it to your downpipes and use it for garden watering. However, the maximum benefit of rainwater tanks is generated when the tank water is used for internal purposes such as toilet flushing and clothes washing as well as for garden watering.  You can also use rainwater to wash your car; top up your swimming pool or fill an ornamental pond. 

How big a tank do I need?

Estimating the right size of a tank requires a combination of experience and calculation and is based on:

  • how much rain falls each year
  • the area of roof available to capture rain – the more surface area connected, the more water you can capture
  • how you plan to use the rainwater
  • the number of people living in your house
  • your water usage rate
  • available space to install a tank.
Appendix A of the ACT's Rainwater tank guidelines for residential properties in Canberra External Link(PDF 3.6MB) provides tables and charts to help you determine a rainwater tank size. The experience of a reputable tank supplier will also be invaluable.
How much will it cost?

Rainwater tank prices vary according to size, material, finish, strength and quality. It is worth comparing prices from several suppliers.

Other costs may include: delivery and installation, hire of a licensed plumber for household connection, plumbing pipes and fittings, guttering and downpipe alterations, stand foundation work, flow restrictor, first flush devices, water pump, associated electrical work and ongoing maintenance.

Will I need a pump?

If your tank is not elevated enough to allow gravity to provide the required water pressure, you will need to install a pump. A pump may be necessary to provide the pressure required for irrigation systems. A pump is usually necessary to boost pressure and flow when using tank water for toilets and washing machines.

Do I need a licence to take water from my rainwater tank?

No. Under the Water Resources Act 2007, there is no need for a licence to take and store rainwater.

Will I reduce my water bill?

You can expect to make some savings on your water bill if you use rainwater instead of mains water in your garden or inside your home. 

What work can I do without a plumbing or electricity licence?

Taking due care, a handy person can install:

  • tanks and stands
  • irrigation systems from a dedicated tank
  • a pressure boosting pump used solely for irrigation
  • rainwater guttering, downpipes and stormwater drains.
What work requires a licensed plumber or electrician?

A licensed plumber must be engaged to install:

  • rainwater plumbing pipes providing water to the house
  • pressure boosting pumps for household rainwater plumbing
  • automatic mains water diverter.

A licensed electrician must be engaged to modify or install:

  • power outlets
  • fixed wiring to pumps or electrical appliances.
For further information, contact the ACT Planning and Land Authority on 6207 6262.
Is a development application or building approval required to install a tank?

The ACT Planning and Land Authority requires the location, size and installation of rainwater tanks to be appropriate to the streetscape character and not to impact on the amenity of residents. A development application (and perhaps building approval) is not required if the tank:

  • is forward of the front building line and buried
  • is not more than 20,000 litres in size
  • does not affect a significant tree
  • is not located in a heritage listed area
  • is no more than 3 metres above natural ground level.

A development application (and perhaps building approval) is required if:

  • the tank is forward of the front building line and is not buried
  • installed within 1.5 metres of a side boundary or rear boundary of the block
  • there are other class 10 structures within 1.5 metres of the boundary (Class 10 structures include pools, garden sheds, gazebos, existing rainwater tanks).

For more information about development applications and building approvals for rainwater tanks contact the ACT Planning and Land Authority on 6207 1926.

Do I need plumbing approval?

The installation of a rainwater tank does not require plumbing approval if the tank is:

  • free standing
  • to be used only for garden or lawn irrigation
  • not delivering rainwater to taps, fixtures or appliances in the house.

All other installations require plumbing approval and compliance wit AS/NZS 3500, Part 1, Section 14 Installation of water supply systems from rainwater tanks.

What are first flush diverters?

First flush diverters and gutter guards are essential for reducing the amount of sediment and other contaminants, such as dirt, bird and animal droppings, entering the tank and polluting the water. When it rains, the first flush of roof water enters the diverter tube. As the water rises in the tube, a ball rises until it seals off the tube. Cleaner water is now diverted into the tank.