Using greywater

Using greywater from your bathroom or laundry on your garden, instead of potable water (drinking water from the mains water system), makes an important contribution towards conserving our precious water supplies.

The amount of greywater produced by your household depends on the water use habits of everyone in your household. For example, how long household members spend in the shower each day, whether you have a water-efficient showerhead or washing machine, how many loads of washing you do each week, etc. On average, a two to three person Canberra household can generate around 300 litres of greywater per day from the hand basin, shower, bath and laundry.

For more detailed information about using greywater simply and safely around the home, see the ACT Government's Greywater use: Guidelines for residential properties in Canberra External Link(PDF 1.3 kB) .

Here are some answers to frequently asked questions about using greywater.

What is greywater?

Greywater is the wastewater from the hand basin, shower, bath, spa bath, washing machine, laundry tub, kitchen sink and dishwasher. The following information does not address blackwater use. Blackwater is the wastewater from the toilet, urinal and bidet. 

Which sources of greywater are suitable for use in the garden?

Generally, washing machine rinse-cycle water and bathroom water are the most suitable sources of greywater for garden watering. If you use low-salt, phosphorus-free detergents you do not need to restrict the use of washing machine water to the rinse cycle, you can use all the laundry water. However, laundry water from soiled nappies or wash water from domestic animals should not be used.

How can I get greywater into the garden?

The simplest systems involve diverting greywater from the laundry and/or bathroom directly to the garden or lawn. This can be achieved by:

  • using a bucket or siphon to transfer water;
  • connecting the washing machine discharge hose to a diversion hose leading to the garden. Before doing this, you may wish to check with your washing machine manufacturer regarding the suitability of using a greywater diversion hose with your washing machine, as a washing machine pump is designed to operate under minimal resistance. To protect your pump from damage, use a large diameter hose and only divert to areas lower than the washing machine;
  • fitting the laundry tub waste pipe with an approved hand-operated diversion valve. You can then easily switch the plumbing diversion device to divert greywater, by gravity, from the laundry tub through a hose to the garden instead of the sewer. This valve must carry a 'Watermark' approval and can only be installed by a licensed plumber; and
  • diverting bathroom water by having a licensed plumber fit an approved diversion valve into the bathroom waste pipe, much like the laundry tub diversion system above. However, this is only an option for houses built on piers, as there is usually no access under houses built on a concrete slab.

Do not distribute greywater with a domestic garden hose that may be used for other purposes.

Can I store greywater to use later?

Untreated greywater must not be stored for more than 24 hours, as it may give rise to offensive odours due to the growth of micro-organisms.

What are the different types of greywater systems?

Generally, greywater systems fall into two types: diversion devices and treatment systems. Diversion devices direct greywater from the laundry or bathroom to the garden for immediate use without making changes to its quality. The greywater is not stored. Treatment systems improve the quality of the wastewater by filtering, disinfecting and treating it.

Can I install a greywater treatment system?

Greywater treatment systems remove the bacterial load and chemical pollutants from greywater so it can be stored for periods longer than 24 hours. Before installing a treatment system, you should consider the costs involved, as well as your responsibility to ensure the system is maintained so it does not create a public health or environmental risk. Greywater treatment systems will require regular maintenance, such as regular cleaning or replacing of filters and periodic de-sludging of the holding tanks. 

Do I need Government approval for a greywater treatment system?

The ACT Government does not have a formal approval process specifically for domestic greywater treatment systems and therefore there is no list of ACT Government approved greywater systems. However, the requirements of the ACT plumbing legislation, the Plumbing Code of Australia and Australian and New Zealand Standard 3500 must be met, and normal plumbing approvals, which can be obtained from the ACT Planning and Land Authority, are required.  

Do I need to use a licensed plumber?

If you intend to intercept greywater before it enters the sanitary plumbing and drainage system (i.e. before it enters the drain hole of a sink, basin, bath or shower) you can do this yourself. This may be a simple setup in which you bucket water from a sink or direct the water from your washing machine outlet (via a hose) to your garden.

However, any work on the sanitary plumbing or drainage system (i.e. to the pipes below your sink, basin, bath or shower) including the installation of diversion valves, must be performed by a licensed plumber or drainer, in accordance with ACT plumbing legislation. The installation of the plumbing work must comply with the Water and Sewerage Act 2000, the Water and Sewerage Regulation 2001 and the Plumbing Code of Australia (PCA). The relevant provision under the PCA which must be met is the Australian and New Zealand Standard 3500 (AS/NZS 3500). All plumbing products installed must comply with this Standard. Complying products must meet the Plumbing Code of Australia product certification authorisation and be marked with "W" for the WaterMark approval scheme. It is important that the plumber you choose is fully aware of these requirements.

What greywater systems are available in the market?

The following list contains links to information about greywater systems approved or accredited in other States or Territories. These links are provided solely for ease of reference to information about a range of greywater systems. They do not constitute an exhaustive list of available greywater systems and provision of this information does not constitute endorsement or approval of any specific product by the ACT Government.

Are there any rebates to help me install a greywater diverter or treatment system?

The ACT Government does not offer rebates for the installation of greywater diverters or treatment systems.

The Australian Government provides rebates for households to install rainwater tanks or greywater systems through its National Rainwater and Greywater Initiative External Link.