Water quality

Water quality

SA Health statement

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 2020-21, SA Water collected 46,401 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 per cent of metropolitan Adelaide samples, 99.96 per cent of country samples and 100 per cent of remote Aboriginal community samples. Overall compliance with the ADWG for health-related parameters was 100 per cent for metropolitan systems, 99.94 per cent for country areas and 99.83 per cent for remote Aboriginal community supplies.

The total number of incidents notified by SA Water during 2020-21 was similar to 2019-20. There was an increase in the number of incidents arising from unauthorised activities at drinking water reservoir reserves, access to which was expanded and they were visited by a growing number of people. These activities did not have a measurable impact on drinking water quality. An extensive proactive flushing program initiated to improve aesthetic aspects of drinking water and remove corrosion products from ageing sections of distribution networks resulted in a greater number of reported chemical exceedances. However, these exceedances were temporary and resolved as part of the program. An audit of properties supplied by the Virginia Pipeline Scheme led to detection of a number of cross connections between drinking water and recycled water pipework. These cross-connections were detected within property boundaries.

There was no evidence that recycled water had entered the public drinking water supply. Protection of the drinking water network has been increased.

Incidents associated with contamination of drinking water storage tanks also increased.

There was a reduction in numbers of incidents reported due to detection of cyanobacteria and enteric protozoa in source water. Cooler summer temperatures and lower winter rainfall may have contributed to the reduction. Incidents associated with water filtration and disinfection were reduced in 2020-21 compared to 2019-20. The number of incidents arising from customer complaints about dirty water was also lower.

Water quality incidents were notified by SA Water in a timely manner. Appropriate remedial actions were implemented and ensured the protection of public health was maintained at all times. No incidents required public notification during the reporting period.

Safe drinking water legislation

The Safe Drinking Water Act 2011 provides the regulatory framework for drinking water providers in South Australia and is administered primarily by SA Health with assistance from local government. Provisions in the Act are underpinned by the ADWG and prescribe requirements for drinking water providers, including:

  • registration of drinking water providers with SA Health
  • development and implementation of risk management plans (RMPs)
  • 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 accredited laboratories for sample testing
  • reporting of water quality test results to SA Health and providing   consumers with drinking water quality information.

SA Water is registered as a drinking water provider and has established RMPs including approved monitoring programs and an incident notification protocol.

SA Water provided water quality testing reports for metropolitan, country and remote community water supplies on a monthly basis with results showing a very high level of compliance. Under the Act, SA Water is required to undergo an annual independent audit. In 2020-21, the seventh audit of SA Water was undertaken since the Act took effect.

A number of representative SA Water drinking water supplies were included in the audit. The audit concluded that SA Water had a very strong culture of prioritising drinking water safety and was operating in compliance with the requirements and intent of the Act. The level of compliance was improved in comparison to the six previous audits and no significant non-compliances were detected. Some opportunities for improvement were identified.

Further information on the Safe Drinking Water Act 2011 can be found at sahealth.sa.gov.au/safedrinkingwateract.

SA Water also provides additional information regarding water quality which can be found at sawater.com.au.

Catchment to tap

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.

Water quality monitoring and testing

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.

The following table summarises routine monitoring and testing activities in our SA Health-registered drinking water supply systems in 2020-21.

Number of sample locations and test analytes – statewide, metropolitan, country and remote Aboriginal communities water supply systems, 2019-20

Drinking water systems

Statewide

Metropolitan

Country

Remote Aboriginal communities

Supply systems

85

8

59

18

Customer tap sample locations

511

177

314

20

Catchment to tap sample locations*

1,478

365

982

131

Catchment to tap routine test analytes

357,957

83,126

264,376

10,455

* Includes customer tap sample locations

Drinking water quality and performance

In 2020-21, we demonstrated robust management of water quality by consistently

providing safe, clean drinking water to our customers.

The following table summarises our performance for health-related parameters of routine samples at customer tap sample locations.

Statewide, metropolitan, country and remote Aboriginal communities drinking water supply systems health-related performance, 2020-21

Health-related parameters

Statewide systems (number of test analytes)

Metropolitan systems 

(number of test analytes)

Country systems

(number of test analytes)

Remote Aboriginal communities

(number of test analytes)

Samples free from E. coli*

99.97% (10,064)

100% (3,228)

99.96 (6,732)

100% (104)

Samples compliant with ADWG health parameters*

99.96% (46,401)

100% (13,309)

99.94% (32,496)

99.83% (596)

Target: 99.90%

Target: 100%

Target: 99.80%

Target: 99.80%

* 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 46,401 routine test analytes from our drinking water supplies (customer tap sample locations) throughout South Australia to determine health-related compliance.

  • We achieved 99.97 per cent E. coli compliance across customer tap sample locations with exceptions in three country systems.
  • Compliance with ADWG health- related parameters across customer tap sample locations was above target at 99.93 per cent.

Although we aim for 100 per cent compliance all the time, the ADWG recognises that occasional exceedances may occur with most guidelines for chemicals based on a lifetime of exposure. In accordance with the guidelines and the interagency Water/Wastewater Incident Notification and

A number of our surface water sources contain high amounts of natural organic matter. As a result, we continue to work towards reducing disinfection by-products that occur due to the interaction between this organic matter and chlorine used as a disinfectant. In 2020-21 we made significant improvements nearly halving the number of disinfection by-product exceedances when compared to the previous financial year. For example, the construction of a granular activated carbon plant within the Wirrina Cove system significantly reduced disinfection by-products from the water.

With a goal to further reduce disinfection by-products, as well as improve the taste and smell of the water, we are progressing with changing the treatment chemicals used to disinfect the water within the Myponga system from chlorine to chloramine. After receiving positive feedback from the Myponga township residents following this change, we completed the second stage of this project in March 2021, which has expanded the chloraminated area to include the townships of Yankalilla, Normanville and Carrickalinga.

In 2020-21 we also undertook planning, design and construction works which will see the remainder of the Myponga system receive chloraminated water in 2021-22, including the major townships of Sellicks Beach, Encounter Bay, Goolwa, Port Elliot, Victor Harbor and Hindmarsh Island.

Year in review_E.coli compliance_2019-20-01

Incident management

We apply the ADWG Framework for Management of Drinking Water Quality which includes two 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 Safe Drinking Water Act 2011 and Safe Drinking Water Regulations 2012.

SA Health defines three 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 notifications

An incident that, without appropriate response or intervention, represents a low risk to human health.

Following is a comparative summary of the Priority Type 1, Type 1 and Type 2 incident notifications reported against the interagency Water/Wastewater Incident Notification and Communication Protocol.

Statewide drinking water supplies number of incidents (metropolitan, country and remote Aboriginal communities)

Reporting period

Priority Type 1

Type 1

Type 2

2020-21

1

45

57

2019-20

1

36

63

2018-19

1

24

54

2017-18*

2

42

90

2016-17#

2

48

159

Note: these notifications do not include wastewater, recycled water and non-drinking supplies.

* Remote Aboriginal communities incidents included in annual reporting from 2017-18.

# Impacted by River Murray blackwater event.

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.

The Priority Type 1 incident was due to high levels of the blue green algae Dolichospermum circinale at Wirrina Cove Water Treatment Plant inlet. The plant was taken offline while it was treated with algicide. During the incident, drinking water was transported from the nearby areas of Normanville, Yankalilla and Myponga to supplement the storage tank at Wirrina Cove.

In 2020-21, the number of Type 1 notifications increased and Type 2 notifications decreased compared with 2019-20. The increase in Type 1 notifications was largely attributed to an increase in recreational access-related incidents, with visitations more than doubling in 2020-21 as reservoir reserves were progressively opened for public access and activities were expanded. When taking into account the increased visitations, the incident rate per 1,000 visitors declined when compared to 2019-20,

showing the overwhelming majority of visitors are doing the right thing when enjoying these spaces. These activities did not have a measurable impact on drinking water quality as considered by SA Health.

There was an increase in cross-connections between drinking water and recycled water reported due to an audit of properties supplied by the Virginia Pipeline Scheme. These occurred within property boundaries with no evidence that recycled water had entered the drinking water network. As part of the audit, these cross connections have been removed and we will continue work with SA Health and the Office of the Technical Regulator to further safeguard these systems. There was also a decrease

in cyanobacteria incidents in our source waters. The reduction in Type 2 notifications is due to a significant decrease in clusters of customer complaints and enteric protozoa incidents.

In 2020-21, we continued our focus on early detection and reporting to external agencies, briefing the Minister for Environment and Water, ensuring prompt corrective action and addressing the causes of preventable Type 1 notifications, such as disinfection failures and filtered water turbidity exceedances. Strategies used to achieve this include refresher training for incident managers and operators, 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 2020-21. 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 2020-21 strategic target for the IRI was 85 per cent compliance.

Criteria used in the Incident Response Index (based on total reportable SA Health Priority Type 1 and Type 1 incident notifications)

Incident reported to relevant agencies by phone immediately

(less than one hour)

Overall strategic 2020-21

target: 85%

Incident entered into the incident management system

in less than two hours

Initial effective response taken within three hours

Written report to Minister for Environment and Water

by 3pm next business day

Root cause analysis completed within 10 working days

Preventive actions implemented within agreed timeframes

  

The continual review and improvement of our incident management processes has positively impacted our overall water quality incident response and performance, maintaining an overall score well above our target.

The Incident Response Index achieved in metropolitan, country and remote Aboriginal communities and overall for 2020-21, compared to 2019-20

System

IRI 2019-20

IRI 2020-21

Statewide (weighted combined metropolitan, country and remote

Aboriginal communities)

98%

93%

Metropolitan

98%

99%

Country

98%

90%

Remote Aboriginal communities

100%

100%

Safe Drinking Water Act audit

In February 2021, we were audited under the Safe Drinking Water Act 2011 (the Act), and successfully met all our legislative requirements. The successful outcome of the audit found:

  • We, and our partner organisations, have a very strong culture of prioritising drinking water safety. This is embedded deeply within the organisation.
  • The drinking water quality management plan is mature and well implemented. As such there are no major gaps or systemic issues identified within the audit.
  • We are acting in compliance with the requirements of the Act, and that the drinking water in the schemes audited is managed in accordance with the intent of the Australian Drinking Water Guidelines.

Overall the auditor concluded there was a very high level of compliance and the identified improvement actions and non-conformances have not impacted the provision of safe drinking water supply.