What is greywater?
Greywater is wastewater discharging from sanitary fixtures and appliances used for personal hygiene. This includes wastewater discharging from the bath, shower, wash handbasin, clothes washing machine and laundry tub.
Greywater does NOT include…….
wastewater from toilets, kitchen waste disposal units and commercial laundry wastes. This is called Black Water. Under the Local Government Act black water must be discharged to a reticulation system if it is available within 30 metres of the property boundary or within 60 metres of any dwelling. In the Tauranga City Council area this is the case for most properties.
What is greywater recycling?
A greywater recycling system collects greywater and uses it for watering the garden or flushing toilets.
Why recycle greywater?
Greywater recycling is mainly found in rural areas where no mains sewerage or water supply systems are available. However, there is growing interest in greywater recycling in urban areas as a water saving and sustainable water use option.
Studies have shown that during the summer around 22% of average household potable water (the drinking water supplied to your tap) is used for outdoor purposes i.e. irrigation. Greywater could be used as an alternative to this.
Also, around 20% of average household potable water is used for flushing the toilet. Again, Greywater could provide a sustainable alternative and save money on your water bill.
I’d like to recycle my domestic greywater – what do I need to know?
What you need to do depends on whether you’ll be using greywater for watering the garden and/or flushing the toilets.
Either way, there are a few rules, which make sure the public and the environment are protected. These are outlined below. In addition, it is recommended that you take some time to understand the different systems and products available and which one is right for your application.
Using recycled water for garden and lawn watering
This needs to be done in accordance with Bay of Plenty Regional Council Rules and should be discussed with them first.
Using recycled water for garden and lawn watering is permitted activity under The Onsite Effluent Treatment Regional Plan – Rule 16. Under this rule you may discharge up to 1cubic meter per day of greywater into land for garden and lawn watering purposes, subject to the following conditions:-
(a) The discharge of greywater into land does not subject the site to slippage,
subsidence, erosion or inundation;
(b) The greywater does not include any commercial laundry wastewater flows;
(c) The discharge is more than 20 metres from any surface water or water
(d) The discharge (recycle) storage capacity shall not exceed 12 hours flow and
any unused flow shall be discharged to the on-site effluent treatment system
on a daily basis;
(e) The discharge of greywater into land shall be at a rate that does not cause
ponding on, or runoff from the area being watered;
(f) The discharge (recycle) of greywater does not cause any emission of
offensive or objectionable odour beyond the boundary of the subject
(g) An outlet solids filter is fitted on the outlet of the greywater storage tank.
The irrigation line used for the dispersal of greywater shall be:
(i) Installed no less than 200 millimetres beneath the surface of the soil;
(ii) Have a minimum of 600 millimetres depth to the water table below the
Irrigation line emitters.
More information on domestic wastewater treatment
or contact the Bay of Plenty Regional Council.
Using recycled water for flushing toilets
If you intend to install a greywater recycling system you will require a Building Consent from Tauranga City Council. You’ll be required to comply with The NZ Building Code, which will include a separate reticulation system for greywater and the requirement for a backflow prevention device to prevent contamination to the potable water supply. Installation will need to be by a registered plumber.
For more information please contact Tauranga City Council on 07 577 7000
Last Reviewed: 23/01/2017