Water quality
Water quality
SA Health and SA Water continue to work cooperatively to ensure the protection of public health in the supply of drinking water across South Australia. SA Water continues to comply with the requirements of the Safe Drinking Water Act 2011 including water quality monitoring, the notification of incidents, and successfully completed an independent audit against criteria in the Act during March and April 2024.
Monitoring of drinking water supplies was in accordance with SA Health approved monitoring programs. During 2023-24, SA Water collected 46,505 samples from drinking water supplies throughout the state. Samples were analysed for compliance with the Australian Drinking Water Guidelines (2011) (ADWG) and results reported to SA Health in line with agreed reporting protocols. Compliance with the ADWG for E. coli was achieved in 100.00 per cent of metropolitan Adelaide samples and 99.93 per cent of regional samples. Overall compliance with the ADWG for health related parameters was 99.99 per cent for metropolitan systems and 99.92 per cent for regional areas.
There was a decrease in the number of detections of E. coli in drinking water samples in 2023-24. Detections were low-level and in isolated samples, with followup samples clear of E. coli. Overall compliance of E. coli monitoring remained high. Incidents were notified and managed under the interagency Water/Wastewater Incident Notification and Communication Protocol and reported in a timely manner Appropriate remedial actions and responses were implemented following incidents to ensure the protection of public health was maintained at all times.
The total number of incidents notified by SA Water during 2023-24 (179) was the same as 2022-23. One Priority Type 1 incident raised during 2023-24 due to the detection of high concentrations (>100,000 cells/ml) of an atypical cyanobacterium Microcystis aeruginosa in the River Murray. The incident was later downgraded following confirmation that it was non-toxic. The algal bloom was closely monitored during its duration to ensure that the water treatment plants were operating effectively for the removal of cyanobacterial cells and taste and odour compounds. There was an increase in the detection of elevated cyanobacteria concentrations in drinking water reservoirs but these were managed appropriately to prevent risks to drinking water quality.
The detection of enteric protozoa (Cryptosporidium and Giardia) in drinking water catchments and source waters was reduced in 2023-24 possibly influenced by lower rainfall in the first 6 months of 2024. There were 3 Type 1 incidents involving detection of enteric protozoa including one in treated product water (Cryptosporidium) and 2 at the inlets to drinking water treatment plants.
The Cryptosporidium detected in the treated water sample was not human infectious. Protozoa were not detected in follow up samples. No faults were detected from the continuousmonitoring of treatment plant performance during the periods when the protozoa were detected. Installation of ceramic membranes for the treatment of wastewash water at the Anstey Hill Treatment Plant provided additional protection for drinking water quality.
The number of incidents (3) for drinking water reservoirs open to recreational activities has decreased since 2022-23 (9). These incidents were managed effectively and did not have a measurable impact on drinking water quality. The detection of high concentrations of toxic cyanobacterium Cylindrospermopsis raciborskii in Lake Alexandrina led to advice being issued to the public not to use Lake Alexandrina for body contact recreational activities. While Lake Alexandrina is not a drinking water source it is used for recreational purposes and continues to be closely monitored.
The Safe Drinking Water Act 2011 (the Act) and Safe Drinking Water Regulations 2012 provide the regulatory framework for drinking water providers in South Australia and are administered primarily by SA Health.
Provisions in the Act are underpinned by the Australian Drinking Water Guidelines (ADWG) and prescribe requirements for drinking water providers, including:
- registration of drinking water providers with SA Health
- development and implementation of risk management plans
- establishment of approved drinking water quality monitoring programs
- notification of incidents or non-compliance
- audits and inspections to determine compliance with the Act
- use of National Association of Testing Authorities (NATA) accredited laboratories
- for sample testing
- reporting of water quality test results to SA Health and providing consumers
- with drinking water quality information.
As a registered drinking water provider, we have established risk management plans, including approved monitoring programs and an incident notification protocol. We provide water quality testing reports for metropolitan and regional water supplies on a monthly basis.
An independent audit was undertaken in March and April of 2024, as required by the Act. The 9-day audit examined a selection of representative drinking water supplies. It encompassed both desktop assessments and on-site visits, which included travelling to South Australia’s largest water treatment plant at Happy Valley, ground water supplies in the South East and some of our Riverland water supplies.
The audit recognised that we comply with the requirements of the Act, and that the drinking water in the schemes audited is managed in accordance with the intent of the ADWG. Highlights identified by the auditor included:
- a drinking water management system that is comprehensive and implemented
- proactive management of drinking water quality that is a core aspect of how we
- operate this has been further enhanced in the past year by adoption of
- a specific drinking water quality policy that outlines how we achieve this aim
- close integration of our partner organisations (Production & Treatment Alliance,
Service Stream and TRILITY)
- a new tank inspection procedure and related training program that has been
- implemented to ensure that tanks are regularly inspected.
While the audit demonstrated a very high level of compliance, 3 non-conformances and a number of improvement actions were identified, as is expected with a detailed assessment. As in previous years, these items will be evaluated and corrective actions will be implemented.
We manage drinking water quality from catchment to tap in line with our Drinking Water Quality Management System to ensure a consistent and reliable supply of high quality, safe drinking water for our customers. This management system is based on the Framework for Management of Drinking Water Quality outlined in the ADWG and endorsed by the National Health and Medical Research Council. The framework outlines good drinking water supply management, based on the best available scientific evidence that will assure drinking water quality and safety at the tap.
We operate 87 drinking water supplies that serve customers across metropolitan and regional South Australia. This includes 2 new drinking water supplies commissioned this financial year at Oodnadatta and Marla. Both sites feature newly constructed desalination plants that use reverse osmosis technology to treat and remove salt and other impurities that are naturally present in the groundwater.
We implement SA Health-approved drinking water quality monitoring programs to ensure the quality of our supply. These programs involve collecting around 409,000 results from samples at various stages of the water supply system, including catchment areas, source water, treatment processes, and distribution networks up to the water meter on individual properties. We monitor for health and aesthetic compliance and to optimise water quality.
Samples are collected by trained field workers to make sure they are taken correctly and that field results have a high degree of integrity. Our Australian Water Quality Centre conducts laboratory analyses in compliance with ISO 9001 Quality Systems and NATA requirements. In 2023-24 we were proud to celebrate 50 years of continuous accreditation to the NATA 17025 Standard.
Number of sample locations and test analytes – statewide, metropolitan, regional supply systems, 2023-24
Drinking water systems | Statewide | Metropolitan | Regional |
Supply systems | 87 | 7 | 80 |
Customer tap sample locations | 514 | 174 | 340 |
Catchment to tap sample locations* | 1,512 | 350 | 1,162 |
Catchment to tap routine test analytes | ≈409,000 | ≈69,000 | ≈340,000 |
*Includes customer tap sample locations
In 2023-24, we demonstrated robust management of water quality by consistently
providing safe, clean drinking water to our customers.
Statewide, metropolitan and regional drinking water supply systems health-related performance, 2023-24
Health-related parameters
| Metropolitan systems (number of test analytes)
| Statewide systems (number of test analytes)
| Regional (number of test analytes)
|
Samples free from E. coli | 99.95% (10,231) | 100.00% (3,179) | 99.93% (7,052) |
Samples compliant with ADWG health parameters* | 99.94% (46,505) Target: 99.90% | 99.99% (12,629) Target: 99.90% | 99.92% (33,876) Target: 99.90% |
*Percentage of routine results at customer tap sample locations within drinking water systems which comply with the ADWG health limits
(including E. coli).
Direct exceedances of the ADWG were used rather than the 95th percentiles for compliance of individual chemical parameters.
Before calculating per cent compliance for health-related chemicals, individual results are rounded to the same number of significant figures as the guideline value in the ADWG (as prescribed in the ADWG and agreed with SA Health).
We analysed 46,505 test analytes from our drinking water supplies (customer tap sample locations) throughout South Australia to determine health-related compliance. We achieved 99.95 per cent E. coli compliance across customer tap sample locations with detections in 5 regional systems.
These E. coli detections all occurred in the presence of chlorine or chloramine residuals at levels sufficient to mitigate risk. Plant operation and residuals from various locations around the time of the detections were reviewed and all were within specifications. Follow-up samples showed consistent residuals, with no E. coli detected.
Compliance with ADWG health-related parameters across customer tap sample locations was above target at 99.94 per cent.
While we strive for 100 per cent compliance at all times, the ADWG acknowledges that occasional exceedances may occur and for most characteristics these occasional excursions beyond the guideline value are not necessarily an immediate threat to health. In accordance with the guidelines and the interagency Water/ Wastewater Incident Notification and Communication Protocol, all detections were immediately communicated to SA Health, investigated by us and corrective actions implemented as agreed with SA Health. SA Health confirmed that the drinking water we provide to customers is safe and that our responses effectively mitigated any risks to public health.
We apply the ADWG Framework for Management of Drinking Water Quality which includes 2 components for the management of incidents:
1. communication
2. incident and emergency response protocols.
Our Water Quality Incident and Emergency Management Protocol is in place and we have a web-based incident management system to record and generate notifications of water quality incidents. These are aligned to the interagency Water/Wastewater Incident Notification and Communication Protocol that is maintained by SA Health to adopt the principles of the ADWG and satisfy requirements of the Act and Safe Drinking Water Regulations 2012.
SA Health defines 3 types of health-related incident classifications based on a precautionary approach:
1. Priority Type 1 incident notification
An incident that, without immediate appropriate response or intervention, could cause serious risk to human health and is likely to require immediate interagency meetings to consider responses. Procedures for Type 1 incident notifications also apply.
2. Type 1 incident notification
An incident that, without appropriate response or intervention, could cause serious risk to human health.
3. Type 2 incident notifications
An incident that, without appropriate response or intervention, represents a low risk to human health.
Number of incidents in statewide drinking water supplies (metropolitan and regional)
Reporting period | Priority Type 1 | Type 1 | Type 2
|
2023-24 | 0 | 50 | 129 |
2022-23 | 2 | 48 | 129 |
2021-22 | 0 | 50 | 86 |
2020-21 | 1 | 45 | 57 |
2019-20 | 1 | 36 | 63 |
Note: these notifications do not include wastewater, recycled water and non-drinking supplies.
Priority Type 1 and Type 1 incidents are immediately reported to SA Health, while all Type 2 notifications are reportable within 24 hours, in line with the interagency Water/Wastewater Incident Notification and Communication Protocol.
In the 2023-24 period, no Priority Type 1 incidents were reported. But the total number of reportable incidents remained consistent with the previous financial year.
The introduction of chlorate Type 1 incident criteria in June 2023 and subsequent SA Health approved extra monitoring locations led to an increase in Type 1 disinfection by-product notifications. Whilst chlorate is not a health parameter currently in the ADWG, SA Health have indicated that it may be incorporated in future editions.
In 2023-24, we continued to address the causes of preventable Type 1 notifications. Strategies used to achieve this include ongoing operational and capital improvements, incident management training, optimisation of our drinking water quality monitoring program and continuous improvement of our Drinking Water Quality Management System.
The proactive water quality management of our water supply systems and the detection and management of risks continued during 2023-24. Changes in reporting criteria issued by SA Health in the interagency Water/Wastewater Incident Notification and Communication Protocol also occurred and contributed to a change in reporting requirements.
The Incident Response Index (IRI) drives and guides correct responses when a Priority Type 1 or Type 1 incident is detected. The IRI is assessed against a number of criteria, with each component in the IRI designed to help manage water quality incidents. Criteria used in the IRI based on total reportable SA Health Priority Type 1 and Type 1 incident notifications are:
* incident reported to relevant agencies by phone immediately (less than one hour)
* incident entered into the incident management system in less than 2 hours
* initial effective response taken within 3 hours
* written report to the Minister for Housing Infrastructure by 3pm the next business day
* root cause analysis completed within 10 working days
* preventive actions implemented within agreed timeframes. The overall 2023-24 strategic target for the IRI is 85 per cent compliance.
The Incident Response Index achieved for metropolitan and regional incidents in 2023-24
System | IRI |
Metropolitan | 100% |
Regional | 96% |
Target | 85% |
