Greywater

Greywater is the water produced from activities at home - showers, baths, spas, laundry tubs and washing machines.

Waste water from your toilet is called 'black water' and is not permitted for re-use. Water from your kitchen sink and dishwasher is also not recommended because it often includes grease and food particles and may have high pH levels.

Washing machines produce up to 25% of a household's waste water. In one week alone, you could pour up to 1,000 litres of water down the drain.

Benefits of Greywater

• Reduces the demands on our potable water supply
• Helps reduce annual water bills
• Provides an alternative water source for watering gardens in times of drought

Disadvantages of Greywater

• If not re-used correctly, greywater may have undesirable health and environmental effects
• Installing a greywater system by a licensed plumber does incur a cost
• On-going maintenance

There are three ways of re-using greywater:

• Manual bucketing - you can collect small quantities of water in buckets for re-use on your garden or lawn. For example - take a bucket into the shower with you. No Council approval required.
• Diversion - greywater diversion devices re-direct greywater for use outside the home on gardens and lawn using sub-surface irrigation. No Council approval is required but there are conditions (*) that must be met. The system must also be installed by a licensed plumber.
• Treatment - greywater treatment systems can be installed for water re-use inside the home (ie: toilet flushing, washing machines) as well as for outside watering. Council approval is required and a licensed plumber must install the system.

* Domestic greywater diversion may be carried out without the prior approval of Council if:

• it is carried out in accordance with the Plumbing and Drainage Code of Practice and,
• a sewage management facility is not installed on the premises concerned, and
• the following performance standards are achieved:
• the prevention of the spread of disease by micro-organisms
• the prevention of the spread of foul odours
• the prevention of contamination of water
• the prevention of degradation of soil and vegetation
• the discouragement of vermin and insects
• ensuring that persons do not come into contact with intreated sewage or effluent (whether treated or not) in their ordinary activities on the premises concerned
• the minimisation of any adverse impacts on the amenity of the premises concerned and surrounding lands

For more information go to: Approval Required for Greywater Use

NSW Guidelines for Greywater Reuse in Sewered, Single Household Residential Premises (PDF)

 

Greywater Diversion - DO and DON'T

This information can be downloaded as a Fact Sheet from the NSW Department of Energy, Utilities and Sustainability website.

The website contains comprehensive information about using greywater.

Go to: NSW Department of Energy, Utilities and Sustainability

Do:

• install a greywater diversion device that has a WaterMark licence (previously a Plumbing Safety licence) and is listed by NSW Health.
• reuse diverted untreated greywater only for sub-surface irrigation (at least 10 cm below the surface of soil or mulch).
• install a greywater diversion device that incorporates some form of non-storage surge reduction (i.e. a tank to even out the sudden flow of greywater from a washing machine or shower to the garden irrigation).
• ensure the greywater diversion device is switched to divert greywater to the sewer after irrigation periods.
• undertake a water balance to estimate the amount of water that can be reused by the household.
• select garden-friendly detergents that are biodegradable and low in phosphorus, sodium, boron and chloride.
• select washing detergents that are low in salt - consider using a powder concentrate, or a liquid washing detergent.
• consider enriching the soil (e.g. adding compost) if irrigating with greywater, especially if located on dune sand or shallow rocky soils.
• monitor plant and soil response to greywater sub-surface irrigation.
• occasionally irrigate with drinking water to disperse salts from the soil (only appropriate during extended periods of zero rainfall).
• consider applying a soil rewetting agent every six months
• ensure that regular maintenance is undertaken, including cleaning out the greywater diversion device filter weekly
• and maintaining the sub-surface irrigation system.
• use irrigation drippers with large openings and use a filter to screen solids when using a diversion device.
• ensure that all pipes are marked or labelled to indicate greywater use.

Don't:

• leave a diversion device on all the time. Treat it like a garden tap and only reuse greywater when the garden needs watering. Greywater is for reuse not disposal.
• reuse toilet or kitchen wastewater.
• reuse greywater during rain.
• reuse greywater from the washing of nappies or soiled clothing.
• reuse greywater when a resident is sick, e.g. has diarrhoea.
• reuse greywater generated by cleaning in the laundry or bathroom, or when using hair dye or other chemicals.
• reuse greywater generated by washing rags used for painting or for maintaining machinery and vehicles.
• reuse greywater to top up rainwater tanks or swimming pools.
• store untreated greywater.
• over-water.
• irrigate with greywater if the household is located on an aquifer that is used for drinking water.
• reuse greywater on fruit, vegetables and plants that will be eaten raw or where fruit has fallen to the ground and could be eaten.
• use greywater to wash paths, driveways or cars.
• allow direct contact with or ingestion of the greywater.
• reuse greywater so that it flows into the streets or down stormwater drains.
• install drippers of a sub-irrigation system within one metre of boundary lines, buildings, inground pools and inground potable water tanks.
• let greywater go beyond the property boundary and cause a nuisance to neighbours.

Useful Links:

www.savewater.com.au/how-to-save-water/in-the-home/grey-water