Greywater is defined as the wastewater from the bath, shower, laundry and hand basins.
Blackwater is defined as the wastewater from the toilets, bidets, urinals, and kitchen sinks.
In most residential premises, the greywater and blackwater streams are combined and divert to the centralised sewerage system or an on-site system such as a septic tank.
Given the prolonged drought conditions experienced in the Bathurst region, many residents are looking for innovative ways to save water. Greywater reuse presents an opportunity to residents to reduce the consumption of the reticulated supply (or tank water), and provide an alternative water source for garden irrigation and some indoor uses such as toilet flushing. Grey water reuse is one of many ways in which a household or individual may reduce its ecological footprint and therefore impact on the local environment.
In line with the guidelines produced by the Department of Primary Industries (Office of Water), greywater reuse can be divided into three different categories:
- Manual bucketing
- Greywater diversion
- Greywater treatment
Council’s “Greywater Reuse (Residential Households)” policy outlines the permissible activities for each of the three different categories. Essentially, manual bucketing and greywater diversion are only allowable for garden irrigation. Greywater treatment systems allow for internal uses such as toilet flushing or clothes washing, as well as garden irrigation.
The Department of Primary Industries (Office of Water) has factsheets and other useful information on its website.
Council can only approve the installation of a Greywater Treatment System which has been approved by NSW Health. Click here to view the list of accredited systems.
A testable dual check valve must be installed with greywater diversion devices and greywater treatment systems (for properties connected to the reticulated drinking water supply). The dual check valve must be installed in accordance with AS/NZ 3500. This is essential for the protection of the reticulated supply.
It is essential to consider that the first step for any household should be to reduce total water usage, and reuse greywater second. Greywater reuse does not provide justification for excessive use of potable water (or rainwater for that matter).
Further it is important to note that most households will not be able to reuse all the greywater generated, regardless of the reuse option adopted. In periods of regular rainfall (especially in winter), there may be limited reuse of greywater for garden irrigation. Each household must undertake a “water balance” assessment to determine the average volume of greywater generated, and the average volume that may be reused.
If you require further information please contact Council’s Environmental, Planning & Building Services Department on (02) 6333 6111.