Water quality

SA Health and SA Water work cooperatively to ensure the continued protection of public health in relation to the supply of drinking water across the state. SA Water complied with all requirements under the Safe Drinking Water Act 2011 including the notification of incidents under the interagency Water/ Wastewater Incident Notification and Communication Protocol.

During 2021-22, SA Water collected 46,101 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 99.97 per cent of metropolitan Adelaide samples, 99.93 per cent of country samples and 100 per cent of remote Aboriginal community samples. Overall compliance with the ADWG for health related parameters was 99.99 per cent for metropolitan systems, 99.93 per cent for country areas and 99.56 per cent for remote Aboriginal community supplies.

The total number of incidents notified by SA Water during 2021-22 (136) was higher than in 2020-21 (103) but most of this was due to an increase in Type 2 incidents. There were no Priority Type 1 incidents during 2021-22.

A treatment plant failure at Gerard required substantial refurbishment and upgrading of operational monitoring. While this is being undertaken the community is being supplied with carted drinking water through the existing distribution system.

High rainfall events led to an increase in the detections of enteric protozoa Cryptosporidium and Giardia) in drinking water catchments and source waters. There were five Type1 incidents involving detection of enteric protozoa at the inlets to drinking water treatment plants (two samples) or in treated product water (three samples). However, the protozoa detected in the treated water samples were not human infectious.

Protozoa were not detected in follow up samples. No faults were detected from the continuous monitoring of treatment plant performance during the periods when the protozoa were detected.

There was an increase in the detections of elevated cyanobacteria concentrations in drinking water reservoirs but these were managed appropriately to prevent risks to drinking water quality.

One third of Type 1 incidents were due to unauthorised recreational activities at drinking water reservoirs. The number of recreational use incidents was slightly lower than in 2020-21. The incidents did not have a measurable impact on drinking water quality.

There was a small increase in the number of detections of E. coli in drinking water samples in 2021-22.

These were isolated low-level detections, with follow up samples clear of E. coli. Overall compliance of E. coli monitoring remained very high.

All water quality incidents were notified by SA Water 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. Other than Gerard no incidents required public notification during the reporting period.

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.

The 85 drinking water supplies we operate serve customers across metropolitan, country and remote Aboriginal communities within South Australia.

To maintain quality, we have SA Health-approved drinking water quality monitoring programs with samples collected and analysed throughout all aspects of the water supply system, including catchment and source water, treatment processes and the distribution network 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. Laboratory analyses are carried out by our Australian Water Quality Centre in accordance with ISO 9001 Quality Systems and the requirements of the National Association of Testing Authorities.

* Includes customer tap sample locations

We apply the ADWG Framework for Management of Drinking Water Quality which includes two components for the management of incidents:

• communication
• 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 three 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.

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 2021-22, there were no Priority Type 1 incidents reported. The number of Type 1 incidents increased and is largely attributed to an increase in chemical detections, disinfection failures and increased rainfall leading to enteric protozoa challenges.

There was an increase in Type 2 incidents due to poor source water quality in the River Murray leading to an increase in bacteriological detections, cyanobacteria and disinfection by-products. There was also an increase in disinfection failures, tank contaminations identified through preventative maintenance, and increased rainfall leading to enteric protozoa detections in source water.

In 2021-22, we continued to address the causes of preventable Type 1 notifications. Strategies used to achieve this include refresher training, optimisation of our drinking water quality monitoring program, ongoing operational and capital improvements, and continuous improvement of our Drinking Water Quality Management System.

The proactive water quality management of targeted water supply systems and detection and management of risks continued during 2021-22. 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.

Incident Response Index

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, including reporting, initial response and longer-term preventive measures. The overall 2021-22 strategic target for the IRI is 85 per cent compliance.