Water quality
SA Health and SA Water continue to work cooperatively to deliver safe, clean drinking water to communities throughout South Australia. SA Water continues to meet all requirements of the Safe Drinking Water Act 2011 including water quality monitoring, the notification and management of defined water quality incidents, and successfully completed an independent audit against the Act’s criteria during March.
Monitoring of drinking water supplies aligned with SA Health approved programs. During 2025-26, SA Water collected 49,666 samples from customer tap locations within drinking water supplies throughout the State. Samples were analysed for microbiological and health-related chemical parameters against the Australian Drinking Water Guidelines (2011) (ADWG) and results reported to SA Health in line with agreed reporting protocols. Compliance for E. coli was achieved in 99.93 per cent of samples at customer tap locations statewide. In addition, overall compliance with the ADWG for health-related parameters was 99.98 per cent for metropolitan systems and 99.97 per cent for regional areas.
In close consultation with SA Health, SA Water has actively expanded its investigative monitoring for per- and polyfluoroalkyl substances (PFAS) for drinking water sources across South Australia. By 30 June 2026, SA Water had tested drinking water supplies covering 98 per cent of their customers. Testing included resampling at major metropolitan reservoirs, such as Barossa, Happy Valley, Hope Valley, Little Para, Millbrook, and Myponga, and regional areas including targeted locations in the River Murray, Mount Gambier’s Blue Lake and surrounding groundwater supplies, Eyre Peninsula and APY Lands. All PFAS results were below detection limits, indicating compliance with the ADWG. This initiative is consistent with the national and local interest in emerging contaminants and provides valuable data to inform future monitoring.
All incidents were managed under the interagency Water/Wastewater Incident Notification and Communication Protocol (WWINC). Coordinated actions by SA Health and SA Water ensured timely communication and immediate remedial responses, fully maintaining public health safeguards.
The total number of reportable incidents notified by SA Water during 2025-26 (189) has increased since 2024-25 (138) including two Priority Type 1 incidents raised during this period. None required public notification. These Priority Type 1 incidents were reported due to the detection of non-infectious Cryptosporidium in drinking water produced at Anstey Hill Water Treatment Plant and Mount Gambier’s Blue Lake. In both cases, full investigations were conducted on the potential source of the Cryptosporidium and changes were made to the operation of the water treatment plants and management of the supplies. Follow up monitoring and ongoing review of water treatment performance and management of the supplies continued for a considerable duration after both incidents. Both events were considered not to represent a significant risk to public health.
The following comparative analysis reviews reportable incidents under the WWINC Protocol, evaluating performance and key trends between the 2024-25 and 2025-26 reporting periods.
- Health-related chemicals rose from 5 in 2024-25 to 26 in 2025-26. This increase was primarily driven by the implementation of stricter ADWG values for lead and manganese in June 2025 and targeted network flushing.
- Significantly wetter conditions for most of the State during 2025-26 contributed to an increase in reported detections of enteric protozoa (Cryptosporidium and Giardia) in drinking water catchments and source waters from 14 reported incidents in 2024-25 to 26 in 2025-26.
- Microbiological detections increased from 8 in 2024-25 to 16 in 2025-26. These detections occurred across metropolitan and regional tanks and distribution networks.
- The number of recorded clustered customer complaint incidents increased from 3 in 2024-25 to 12 in 2025-26. Most of these complaints were from dirty water in metropolitan Adelaide or taste and odours in drinking water because of cyanobacteria blooms in source waters. These complaints had aesthetic impacts only.
- A decrease in the reported incidents from potential contamination in surface water and/or distribution network mains and tanks from 45 in 2024-25 to 39 incidents in 2025-26. This includes a reduction from 7 (2024-25) to 4 (2025-26) incidents in drinking water reservoirs open to recreational activities with most involving non-compliant water access including swimming. These incidents did not have a measurable impact on drinking water quality.
- The number of reported incidents for elevated cyanobacteria concentrations in drinking water source waters including River Murray and reservoirs decreased to 15 in 2025-26 compared to 19 detections in 2024-25.
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 SA Health-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 2026, as required by the Act. Conducted over 8 days, the audit assessed a selection of representative drinking water supplies through a combination of on-site inspections and desktop reviews. Site visits included the Little Para Water Treatment Plant and its associated metropolitan network, along with regional sites of Berri, Wirrina Cove, Lucindale, Padthaway, and the Aboriginal community of Gerard. Desktop audits were also completed for remote Aboriginal communities of Mimili and Yunyarinyi.
The audit confirmed compliance with the requirements of the Act and recognised that we have implemented a comprehensive risk management plan and supporting framework that is demonstrably resulting in improvements to the safety and quality of water being provided to South Australians. Highlights identified by the auditor included:
- The breadth and frequency of water quality training programs.
- Delivery of both short- and long-term improvements, including filter repair works and broader system enhancement initiatives at Wirrina Cove.
- Research and development capability, including in-house scientific expertise that has led to beneficial outcomes for water quality management.
- The high standard of organisation at the Port Elliott stores.
- Reactive works – Service Stream allowing the audit of an emergency hydrant replacement in which there was significant time pressure to restore supply.
- Positive engagement from staff all through the audit, including from our partner/ contractor organisations.
- While the audit was positive overall, 3 non-conformances and a number of improvement actions were identified. Consistent with previous years, these matters will be addressed through established corrective action processes and achieved in a timely manner with regular reporting to SA Health.
Our Drinking Water Quality Management System adopts a proactive, whole-of-system approach to ensure the safety and reliability of drinking water at every stage, from catchment to customer tap. The system is aligned with the Framework for Management of Drinking Water Quality outlined in the ADWG and endorsed by the National Health and Medical Research Council. The framework is based on the best available scientific evidence and supports continuous improvements in water quality management.
We operate 91 drinking water supply systems serving customers across metropolitan, regional and remote South Australia. This included a new drinking water supply commissioned in August 2025 located at Marree. The site features a newly constructed desalination plant that uses reverse osmosis technology to treat and remove salt and other impurities that are naturally present in the ground water.
We implemented SA Health-approved drinking water quality monitoring programs, ensuring the quality of our supply. These programs involve collecting over 445,000 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 our trained field workers to make sure they are taken correctly and field results have a high degree of integrity. The AWQC, our laboratory services, conducts laboratory analyses in compliance with ISO 9001 Quality Systems and NATA requirements.
Number of sample locations and test analytes – statewide, metropolitan and regional water supply systems, 2025-26
Drinking water systems | Statewide | Metropolitan | Regional |
Supply systems | 91 | 7 | 84 |
Customer tap sample locations | 533 | 173 | 360 |
Catchment to tap sample locations* | 1,562 | 342 | 1,220 |
Catchment to tap routine test analytes | ≈445,000 | ≈65,000 | ≈380,000 |
*Includes customer tap sample locations
In 2025-26, 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, 2025-26
Health-related parameters | Statewide | Metropolitan | Regional |
Samples free from E. coli | 99.93% (10,457) | 99.94% (3,189) | 99.93% (7,268) |
Samples compliant with ADWG health parameters* | 99.97% (49,666) | 99.98% (12,860) | 99.97% (36,806) |
Target: 99.90% | Target: 99.90% | 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.
Prior to 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 49,666 samples from our drinking water supplies (customer tap sample locations) throughout South Australia to determine ADWG health-related compliance.
- Statewide E. coli compliance achieved 99.93 per cent, exceeding our performance target. Isolated non-compliance events were recorded in 2 metropolitan and 5 regional systems. Comprehensive investigations were undertaken for each event, including assessment of treatment performance, disinfectant residuals and monitoring results from surrounding locations. Follow-up sampling confirmed the absence of E. coli and the necessary corrective actions were promptly implemented to ensure the ongoing safety and reliability of drinking water supplies.
- Overall compliance with all ADWG health-related parameters achieved 99.97 per cent, also exceeding our targets and reinforcing the continued safety and reliability of our water supplies. The number of lead exceedances increased during the reporting period. This was partly attributable to the adoption of the lower ADWG lead guideline value, together with operational challenges associated with changing population dynamics and reduced water demand in some remote community water supplies. Targeted flushing programs have been implemented in affected systems to improve water turnover and maintain water quality.
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 were implemented as agreed. SA Health confirmed that the drinking water we provide to customers is safe, and 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:
- communication
- incident and emergency response protocols.
Our Water Quality and Environmental Incident Management Protocol ensures we are prepared to respond swiftly and effectively to any water quality issue. We use a web-based incident management system to record, track and generate notifications for all water quality incidents.
This is aligned with the interagency Water/ Wastewater Incident Notification and Communication Protocol that is maintained by SA Health. This protocol adopts the principles of the ADWG and meets the regulatory 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:
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.
Type 1 incident notification
An incident that, without appropriate response or intervention, could cause serious risk to human health.
Type 2 incident notification
An incident that, without appropriate response or intervention, represents a low risk to human health.
Statewide drinking water supplies number of incident notification (metropolitan and regional)
Reporting period | Priority Type 1 | Type 1 | Type 2 |
2025-26 | 2 | 53 | 134 |
2024-25 | 0 | 45 | 93 |
2023-24 | 0 | 50 | 129 |
2022-23 | 2 | 48 | 129 |
2021-22 | 0 | 50 | 86 |
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 2025-26, two Priority Type 1 incidents were reported following the detection of Cryptosporidium at Anstey Hill Water Treatment Plant and Mount Gambier‘s Blue Lake. Subsequent assessment confirmed the organisms were non-infectious and posed no significant risk to public health.
Overall, the number of reportable incidents increased compared with previous years. This increase was primarily driven by a combination of enhanced monitoring and detection capabilities, infrastructure-related issues, operational events, variable source water conditions, and improved reporting practices. Updates to the Australian Drinking Water Guidelines, and SA Health’s Water/Wastewater Incident Notification and Communication Protocol, also expanded notification and reporting requirements during the reporting period.
Despite the overall increase in notifications, reductions were achieved across several incident categories, reflecting the effectiveness of ongoing improvements in treatment processes, operational controls, asset management practices and preventative risk management measures. These outcomes demonstrate continued progress in strengthening drinking water quality management and reducing key risks across South Australia.
Throughout 2025-26, we remained focused on reducing preventable Type 1 notifications through targeted operational improvements, infrastructure investment, enhanced monitoring programs and continued strengthening of our Drinking Water Quality Management System. We maintained a proactive approach to managing drinking water quality risks across our supply systems, with an emphasis on early identification, assessment and mitigation of potential issues.
Updates to SA Health reporting requirements were incorporated into our systems, procedures and training programs to support ongoing compliance, timely communication and effective incident management. Together, these activities contributed to the resilience of our drinking water systems.
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 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 2025-26 strategic target for the IRI is 85 per cent compliance.
The Incident Response Index achieved for metropolitan and regional incidents in 2025-26
System | IRI |
Metropolitan | 100% |
Regional | 96% |
Target | 85% |