Summary of Australia's Water Reuse Guideline or Regulation for Centralized Non-potable Reuse
This page is part of the EPA’s REUSExplorer tool, which summarizes the different country level regulations or guidelines for water reuse for a variety of sources and end-uses.
The source water for this summary are Stormwater and Treated Municipal Wastewater.
- Technical basis
- Applications of centralized non-potable reuse approved for use in Australia
- Water reuse category/type
- Additional context and definitions
- Centralized non-potable reuse specifications (table)
- Upcoming regulations
- References
- Disclaimer
This page is a summary of the country’s water reuse law or policy and is provided for informational purposes only. Please always refer to the country for the most accurate and updated information.
In Australia, centralized non-potable reuse The use of recycled water for centralized non-potable reuse where the water does not derive from the same site where it is to be reused. Can include, but is not limited to, toilet flushing, dust control, soil compaction, fire protection, commercial laundries, vehicle washing, street cleaning, snowmaking, and other similar uses. Excludes on-site non-potable water reuse and the use of recycled water for agriculture or landscaping. applications include garden watering, car washing, golf course irrigation, among others. The sources of water stormwaterPrecipitation that is collected from land or impervious surfaces at a district or regional scale for the purpose of beneficial reuse. Rainwater collection at the building scale is classified separately under 'onsite collected waters.’ and treated municipal wastewater Treated wastewater effluent discharged from a centralized wastewater treatment plant of any size. Other terms referring to this source of water include domestic wastewater, treated wastewater effluent, reclaimed water, and treated sewage. are specified by Australia as stormwater and sewage (either combined or separate graywater and blackwater). For Australia, stormwater includes rain draining from roofs, roads, footpaths and other ground surfaces, into stormwater catchment systems. The write-up adapted Australia’s terms when discussing sources or uses of water to match the Regulations and End-Use Specifications Explorer's (REUSExplorer's) terms.
Check out how Australia uses stormwater for potable water reuse.
Australia uses stormwater for a variety of applications, including centralized non-potable reuse and potable water reuse. Browse the potable water reuse summary page.
Technical basis
Australia has developed guidelines to support the use of stormwater and treated graywater and blackwater for centralized non-potable reuse applications, including for garden watering, car washing, toilet flushing, clothes washing, agricultural and urban irrigation, fire protection and industrial uses such as cooling water (NWQMS, 2006; 2009). Similar to the World Health Organization (WHO) water reuse guidance, Australia uses health-based microbial log-reduction targets (LRT) and chemical concentration targets for water quality monitoring (NWQMS, 2006; NWQMS, 2022; WHO, 2017). These LRT and chemical concentration targets vary based on the source of water and its different end uses, allowing the risk assessment of microbial and chemical hazards that could be present in source waters to determine benchmark risks. Australian guidelines use disability adjusted life years (DALYs) for microbial hazards only, converting the estimated probabilities of infection or illness into burden of disease (NWQMS, 2006). DALYs are used to weigh health impacts in terms of severity and duration of disease and the number of people affected. One DALY is equivalent to the loss of one year of full health and it is the sum of years of life lost due to premature mortality (YLLs) and years lived with a disability (YLD) associated to a specific disease or health condition prevalence (WHO, 2023). In drinking water, DALYs are primarily used for microbial hazards, with 10-6 DALYs per person per year (pppy) being approximately equivalent to 1 case of diarrheal disease per 1,000 people per year. Australia set a benchmark risk threshold of 10-6 DALYs per person per year (pppy) for centralized non-potable water reuse. This risk threshold applies to microbial log-reduction targets (LRTs) only, and chemical concentration targets follow the Australian drinking water guidelines (ADWG, 2022).
Treatment guidelines are summarized in the table by source and end use. The technical basis for developing specifications and/or removal of debris, microbial contaminants, and other relevant indicators is specified within Australia’s guidance documents for water recycling (NWQMS, 2006; 2008; 2009). The guidelines are intended to be used as an authoritative reference for states and territories in Australia to provide the scientific basis for implementing regulations.
Centralized non-potable water reuse applications approved for use in Australia
The National Water Quality Management Strategy (NWQMS) (2006) defines the following specific centralized non-potable water reuse applications for treated graywater and blackwater:
- Residential garden watering
- Car washing
- Toilet flushing
- Clothes washing
- Agriculture and horticulture
- Golf course irrigation
- Irrigation for urban recreational and open space
- Fire protection
- Fire-fighting systems
- Industrial uses (including cooling water)
NWQMS (2009) defines the following specific centralized non-potable water reuse applications for captured stormwater:
- Irrigation of playing fields
- Irrigation of golf courses
- Irrigation of bowling greens
- Irrigation of parks and gardens
- Water features and ponds
- Food crop irrigation (homegrown and commercial)
- Toilet flushing
- Washing machine use
- Car washing
- Roadmaking or dust control
- Street cleaning
- Firefighting
Additional centralized non-potable reuse applications for stormwater, treated graywater, and blackwater are not specified.
Water reuse treatment category/type
Australia states that recycled water that meets the defined health-based microbial LRT and chemical concentration targets specified by the national, state, or territory authority is considered safe for the specified end use.
Treatment guidelines are provided for centralized non-potable water reuse in Australia. NWQMS (2006; 2008) outlines specific treatment processes that are known in water treatment engineering:
- Primary: The physical treatment process to remove suspended solids, organic nitrogen, phosphorus, heavy metals, some parasites and some particulate-associated microorganisms.
- Secondary: The removal of dissolved and suspended organic material through sedimentation, biological treatment and/or chemical treatment. This level of treatment reduces microbial pathogens, biodegradable organics, volatile organic compounds and nutrients.
- Tertiary: The removal of suspended solids, biological oxygen demand and pathogenic organisms. Different levels of tertiary treatment include dual-media filtration with coagulation, membrane filtration, reverse osmosis, chlorination, ozonation, activated carbon, advanced oxidation, disinfection and ultraviolet light. These reduce microbial pathogens and chemical hazards.
Additional context and definitions
NWQMS (2006) and NWQMS (2008; 2009) comprise the first and second phase of the Australian Guidelines for Water Recycling, respectively. The water quality targets, including chemical concentrations and microbial treatment performance (e.g., LRTs of pathogens in source waters), are the key health-based targets for centralized non-potable water reuse. The guidelines are intended to be used as an authoritative reference for states and territories in Australia to provide the scientific basis for implementing regulation.
NWQMS (2006; 2008; 2009) provides guidance on preventative measures for recycled water systems for centralized non-potable water reuse. Appropriate storage methods for stormwater or treated graywater and blackwater include lagoons, constructed or natural wetlands, subsurface wetlands, managed aquifer recharge and storage tanks. Australia encourages the collection and recycling of water for centralized non-potable reuse, but underscores to defer to state and territories for regulations which include:
- Contact of regulatory authority to determine specific requirements for recycled water harvesting schemes
- Adoption of recycled water plumbing codes (e.g., color coding)
- Buffer zones, tree and shrub screens, fencing
- Management controls
- Prohibition of recycled water use in specific areas
- Identification of appropriate treatment processes
- Identification of on-site controls (e.g., buffer zones, control of access, method, time, and rate of application)
Centralized non-potable water reuse specifications
The specifications presented in the table include some parameters to be monitored in non-potable recycled water in Australia. Microbial LRTs and chemical concentration targets are not specified for graywater, but a general method for determining microbial LRTs is provided (NWQMS, 2006). The microbial LRTs on the table were derived from first principles through Quantitative Microbial Risk Assessment (QMRA) techniques using concentrations from raw sewage observed in Australia (South Australia Health, personal communication, November 28, 2023; NWQMS, 2008). The LRTs calculation assume different levels of exposure depending on the application, and pathogen doses equivalent to 10-6 DALY, i.e., 1.6×10-2 Cryptosporidium, 2.5×10-3 rotavirus and 3.8×10-2 Campylobacter (NWQMS, 2006; 2008). The NWQMS federal guidelines provide detailed information about these parameters (NWQMS, 2006; 2008; 2009).
Summary of Australia's Centralized Non-potable Reuse Specifications
| Recycled Water Class/Category | Source Water Type | Water Quality Parameter | Specificationsa | Sampling/Monitoring Requirements (Frequency of monitoring; site/ location of sample; quantification methods)b |
|---|---|---|---|---|
|
Centralized non-potable water reuse |
Stormwater |
Disinfection of viruses and bacteria |
>1.5 log-reduction |
Not specified |
|
Disinfection of protozoan parasites |
>0.8 log-reduction |
|||
|
E. coli |
<10 CFU/100 mL (median concentration) |
|||
| Turbidity |
<25 NTU (median) 100 NTU (95th percentile) |
|||
| Ironc | <9.6 mg/L (median) | |||
| Treated graywater and blackwater | Enteric protozoa (e.g., Cryptosporidium) |
5.0 log-reduction (commercial food crops) 3.5 log-reduction (garden irrigation) |
||
| Enteric virus (e.g., rotavirus) | 6.0 log-reduction (commercial food crops, and garden irrigation) | |||
| Enteric bacteria (e.g., Campylobacter) |
5.0 log-reduction (commercial food crops) 4.0 log-reduction (garden irrigation) |
Source = NWQMS (2006; 2009)
a Australia uses guideline chemical concentrations published in the Australian drinking water guidelines (NWQMS, 2022).
b Information about sampling and monitoring requirements such as frequency, site and quantification methods not specifically listed in the table was not explicitly specified in the state-specific regulations.
c Monitored for its impact on soils, not for public health reasons (South Australia Health, personal communication, November 28, 2023)
Upcoming regulations
No upcoming reuse regulations related to centralized non-potable water reuse were found for Australia.
References:
Geneva: World Health Organization (WHO). 2017. Potable reuse: Guidance for Producing Safe Drinking-Water.
Geneva: WHO. 2023. Disability-adjusted life years (DALYs).
National Water Quality Management Strategy (NWQMS). 2022. Australian Drinking Water Guidelines (ADWG) 6 (version 3.8).
NWQMS. 2009. Australian Guidelines for Water Recycling: Managing Heath and Environmental Risks (Phase 2). Stormwater Harvesting and Reuse.
NWQMS. 2008. Australian Guidelines for Water Recycling: Managing Heath and Environmental Risks (Phase 2). Augmentation of Drinking Water Supplies.
NWQMS. 2006. Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1).
Please contact us at waterreuse@epa.gov if the information on this page needs updating or if this state is updating or planning to update its laws and policies and we have not included that information on the news page.