Management of Drinking Water in Australia
Safe drinking water is essential to sustain life. Therefore, every effort needs to be taken to ensure that drinking water suppliers provide consumers with water that is safe to use. The Australian Drinking Water Guidelines (the ADWG) are intended to provide a framework for good management of drinking water supplies that, if implemented, will assure safety at point of use. The ADWG have been developed after consideration of the best available scientific evidence. They are designed to provide an authoritative reference on what defines safe, good quality water, how it can be achieved and how it can be assured. They are concerned both with safety from a health point of view and with aesthetic quality.
The ADWG are not mandatory standards, however, they provide a basis for determining the quality of water to be supplied to consumers in all parts of Australia. These determinations need to consider the diverse array of regional or local factors, and take into account economic, political and cultural issues, including customer expectations and willingness and ability to pay. The ADWG are intended for use by the Australian community and all agencies with responsibilities associated with the supply of drinking water, including catchment and water resource managers, drinking water suppliers, water regulators and health authorities.
1.1 Guiding principles
The ADWG contain a great deal of information about management of drinking water systems, monitoring and the vast array of contaminants that may be present in drinking water. An ever-increasing knowledge base means that the document has continued to grow both in detail and complexity. Although the increased information needs to be included, a danger is that the fundamental principles vital to ensuring safe drinking water quality become obscured in the detail. These fundamental principles, described below, should always be remembered.
The greatest risks to consumers of drinking water are pathogenic microorganisms.Protection of water sources and treatment are of paramount importance and must never be compromised. Waterborne pathogens can cause outbreaks of illness affecting a high proportion of the community and in extreme cases causing death. How much treatment is needed will depend on the level of protection of water supplies. Completely protected groundwater may not require treatment, but all other supplies will require continuous disinfection. If water supplies are not completely protected from human and livestock waste, filtration is likely to be required.
Disinfection is the single process that has had the greatest impact on drinking water safety. There is clear evidence that the common adoption of chlorination of drinking water supplies in the 20th century was responsible for a substantial decrease in infectious diseases. Disinfection will kill all bacterial pathogens and greatly reduce numbers of viral and most protozoan pathogens. Combined with protection of water sources from human and livestock waste, disinfection can ensure safe drinking water. In the absence of complete protection of source water, filtration is likely to be required to improve the removal of viruses and protozoa.
All waterborne disease outbreaks are avoidable. Pathogens can only cause disease and death in humans if water source protection, pathogen removal by disinfection or filtration, or integrity of distribution systems fail.
1–2 Australian Drinking Water Guidelines
Chemical byproducts of disinfection have been suggested as potential health risks. However, the possibility of such health risks remains highly uncertain in comparison to the well-established risks from inadequate disinfection and contamination of water supplies with pathogens. Therefore, although
concentrations of byproducts should be kept as low as possible, efforts to achieve this should never jeopardise effective disinfection. The drinking water system must have, and continuously maintain, robust multiple barriers appropriate to the level of potential contamination facing the raw water supply. The multiple barrier approach is universally recognised as the foundation for ensuring safe drinking water. No single barrier is effective against all conceivable sources of contamination, is effective 100 per cent of the time or constantly functions at maximum efficiency. Robust barriers are those that can handle a relatively wide range of challenges with close to maximum performance and without suffering major failure. Although it is important to maintain effective operation of all barriers, the advantage of multiple barriers is that short-term reductions in performance of one barrier may be compensated for by performance of other barriers. Prevention of contamination provides greater surety than removal of contaminants by treatment, so the most effective barrier is protection of source waters to the maximum degree practical. Knowing how many barriers are required to address the level of potential contamination in individual systems is important. This requires a thorough understanding of the nature of the challenges and the vulnerabilities of the barriers in place. In terms of reliability, there is no substitute for understanding a water supply system from catchment to consumer, how it works and its vulnerabilities to failure. Finally, a robust system must include mechanisms or failsafes to accommodate inevitable human errors without allowing major failures to occur. Any sudden or extreme change in water quality, flow or environmental conditions (e.g. extreme rainfall or flooding) should arouse suspicion that drinking water might become contaminated. Disease outbreaks from drinking water are almost invariably linked to changes in measurable water quality parameters or to the failure of treatment processes to cope with extreme weather events such as high rainfall and flooding. Water treatment processes generally function best under steady state conditions, and performance can seriously deteriorate when there are major fluctuations in quality or flow. It is vitally important that water quality after treatment should remain as constant as possible, no matter how much the quality of the source water varies. Operators and managers need to be aware of normal operating requirements, the measurement criteria that define normal operation and the enormous risks that can be associated with operating outside normal limits. System operators must be able to respond quickly and effectively to adverse monitoring signals.
Sudden changes in water quality or flow are likely to be a sign of imminent problems; such variations should always trigger appropriate responses. Wherever possible, key processes should be monitored continuously. Operators and managers must have the knowledge and appropriate responsibility to implement the necessary responses, which could range from modifying treatment processes to, in extreme cases, advising health regulators to consider issuing public advice such as ‘boil water’ notices or shutting down water supplies. Previous water quality failures or ‘close calls’ should be studied so that operators are aware of the relationship between operational indicators and subsequent water quality failures. Even seemingly small faults should be addressed because these can accumulate and lead to a serious incident. Many waterborne disease outbreaks are caused by a combination of faults.
Australian Drinking Water Guidelines 1–3
System operators must maintain a personal sense of responsibility and dedication to providing consumers with safe water, and should never ignore a consumer complaint about water quality. Consumers are the ultimate assessors of water quality. Consumers may not be able to detect trace concentrations of individual contaminants, but their ability to recognise change should not be discounted. In some cases, consumer complaints may provide valuable information on potential problems not detected by testing water quality or monitoring treatment processes. Water quality testing has limitations and there are many possibilities for contamination of water in reticulation systems after treatment.
All consumer complaints should be investigated to ensure that otherwise undetected problems that might compromise drinking water safety have not occurred. Meeting reasonable consumer expectations and maintaining confidence in the water supply is vitally important. Ensuring drinking water safety and quality requires the application of a considered risk management approach. The process of keeping drinking water safe is one of risk management. This requires steering a sensible course between the extremes of failing to act when action is required and taking action when none is necessary. Lack of action can seriously compromise public health, whereas excessive caution can have significant social and economic consequences. Corrective action or system upgrades should be undertaken in a considered, measured and consultative manner. Failure to act when required (e.g. failing to shut down a system when disinfection is not working effectively) may lead to an outbreak of waterborne disease. Acting when not required (e.g. issuing a ‘boil water’ notice when that is not necessary) is usually less severe in the short term, but repeated occurrences waste resources and are likely to cause complacency in the long term, leading to failure to respond when it is truly necessary. Similarly, failing to install a treatment process when required could lead to waterborne disease; however, installing treatment processes that are not required could have a high financial cost and divert funds needed elsewhere. Risk management is about taking a carefully considered course of action. As the obligation is to ensure safe water and protect public health, the balancing process must be tipped in favour of taking a precautionary approach.
Drinking water is defined as water intended primarily for human consumption, either directly, as supplied from the tap, or indirectly, in beverages, ice or foods prepared with water. Drinking water is also used for other domestic purposes such as bathing and showering. With the exception of bottled or packaged water, the ADWG apply to any water intended for drinking irrespective of the source (municipal supplies, rainwater tanks, bores etc) or where it is consumed (the home, restaurants, camping areas, shops etc). Bottled water and packaged water are subject to the Food Standards Code (ANZFA 2001). The ADWG do not address water used for specialised purposes such asrenal dialysis and some industrial purposes where water of a higher quality than that specified in the Guidelines may be required.
A wide range of measurable characteristics, compounds or constituents can be found in water and may affect its quality. They fall into several categories:
• physical
• microbial
• chemical, including
– inorganic chemicals
– organic compounds
– pesticides
• radiological.
Appearance, taste and odour are useful indicators of quality because they are generally the characteristics by which the public judges water quality. However, water that is turbid or coloured, or has an objectionable taste or odour, may not be unsafe to drink. Conversely, the absence of any unpleasant qualities does not guarantee that water is safe.The safety of water in public health terms is determined by its microbial, physical, chemical and radiological quality; of these, microbial quality is usually the most important.
GUIDELINE VALUES
The ADWG include two different types of guideline value:
• A health-related guideline value, which is the concentration or measure of a water quality characteristic that, based on present knowledge, does not result in any significant risk to the health of the consumer over a lifetime of consumption.
• An aesthetic guideline value, which is the concentration or measure of a water quality characteristic that is associated with acceptability of water to the consumer, e.g. appearance, taste and odour.
The guideline values should be used in two separate but complementary ways: as action levels for the short-term verification of drinking water quality and as a means to assess performance over the longer term (e.g. over a 12-month period). Using a guideline value for short-term verification entails assessing whether individual results conform to the requirements of good quality water. If a value is exceeded, some form of immediate corrective action will generally be initiated. For example, if a guideline value for a health-related characteristic is exceeded, the response should be to take immediate action to reduce the risk to consumers, and, if necessary, to advise the health authority and consumers of the problem and the action taken. If the characteristic affects only aesthetic quality, the action may be to advise the community of deterioration in water quality.
When guideline values are used in assessing overall performance (e.g. as presented in an annual report) the aim is to assess whether management strategies are effective. The assessment is used to identify emerging problems and to determine priorities for improvement. Resulting actions will generally be applied in the longer term.
The guideline values relate to the quality of water at the point of use (e.g. kitchen or bathroom tap). They apply to reticulated water at the consumer’s tap, rainwater for drinking, and source water if it is to be used without prior treatment. This does not, however, imply that the drinking water supplier is responsible for water quality problems caused by plumbing or other factors within a consumer’s property. However, although it is not possible to control consumers’ actions, suppliers should consider how drinking water quality may be affected in private plumbing systems and provide appropriate
information to consumers.
The drinking water supplier should ensure that the quality of water in the reticulation mains meets the guideline values or agreed levels of service. The drinking water supplier would normally monitor quality in a service pipeline directly off a water main selected to represent the quality of water in the system. This is not usually within a private consumer’s property. However, it may sometimes be necessary to check at the consumer’s tap, either to confirm that chosen distribution sampling points are representative for microbial monitoring, to investigate specific problems such as leaching of metals into water, or as a consumer service.
The guideline values define water that, based on current knowledge, is safe to drink over a lifetime; that is, it constitutes no significant risk to health. For most of the water quality characteristics discussed, there is a grey area between what is clearly safe and what is clearly unsafe. Often the latter has not been reliably demonstrated and the guideline values always err on the side of safety. Therefore, for most characteristics, occasional excursions beyond the guideline value are not necessarily an immediate threat to health. The amount by which and the duration for which any health-related guideline value can be exceeded without raising concerns for public health depends on the particular circumstances. Exceeding a guideline value should be a signal to investigate the cause and, if appropriate, to take remedial action. If the characteristic is health related, the relevant health authority should be consulted.
Nevertheless, the ADWG provide the minimum requirements for drinking water of good quality, both aesthetically and from a public health viewpoint. Water suppliers should adopt a preventive risk management approach, as stipulated in the ADWG, to maintain the supply of water at the highest
practicable quality. The guideline values should never be seen as a licence to degrade the quality of a drinking water supply to that level.
1.4 Community consultation
The ADWG are intended to provide consumers with safe and aesthetically pleasing water and ultimately it is consumers who will be the final judges of water quality. It is vitally important that consumers are viewed as active partners in making decisions about drinking water quality and the levels of service to be adopted. Community expectations and willingness to pay must be considered. It is the responsibility of drinking water suppliers to keep the community fully informed about water quality, existing problems and needs for improvement. Consumers also need to be informed about their responsibilities in relation to domestic plumbing and of any possible issues associated with the interaction of mains water with this plumbing.
1.5 Development of the Guidelines
National guidance for drinking water were first published by the National Health and Medical Research Council (NHMRC) in 1972 as Desirable Standards for Public Water Supplies in Australian Capital Cities adopting the Biennial Conference of Engineers Criteria and Objectives for Water Quality for Capital Cities (1969). The NHMRC standards were updated in 1975 as Recommended Quality Criteria for Drinking Water and in 1977 as Desirable Quality for Drinking Water. In 1980, Desirable Quality for Drinking Water was revised and jointly published with the Australian Water Resources Council (AWRC). This was considered a signifi cant advance in water quality management because, for the fi rst time, water supply and health authorities in Australia combined to produce a single guideline document. The 1980 guidelines were based on published criteria and standards recommended by overseas and international agencies, in particular the 1971 International Standards for Drinking Water of the World Health Organization (WHO). Following a review of the 1980 Guidelines, and taking into consideration the 1984 WHO Guidelines for Drinking-Water Quality, the NHMRC and the AWRC published the Guidelines for Drinking Water Quality in Australia in 1987. In 1996, the NHMRC and the Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ, formerly AWRC) published the ADWG. The Guidelines were based on working
papers and assessments prepared by the WHO expert panels, and refl ected recent improvements in understanding problems of water quality. Referenced material included scientifi c papers, Guidelines published by overseas agencies, issues papers prepared by Australian water authorities and assessments made by the NHMRC. Only key references were cited, particularly those that were used as a basis for determining guideline values. The guideline values in the 1996 ADWG were based primarily on the latest WHO recommendations, and any departures from these were detailed in the text. It should be noted, however, that the WHO Guidelines for Drinking Water Quality seek to defi ne drinking water which, as well as being safe, is aesthetically acceptable, whereas the emphasis in the Australian Guidelines is on producing drinking water that is safe and of good aesthetic quality.
During the development of the ADWG, it became evident that undertaking a major review of the ADWG in the future would be time consuming and resource intensive. To improve development and ensure that the Guidelines continued to represent the latest scientific evidence, the NHMRC and ARMCANZ agreed to initiate a ‘rolling revision’ process for the ADWG. Through this process, the Guidelines would remain under constant revision, with specific issues identified for review as required. In 1998, NHMRC and ARMCANZ established a joint committee, the Drinking Water Review Coordinating Group, to oversee and manage the review process. In 2001–2002, ARMCANZ and the Australia and New Zealand Environment Conservation Council were replaced with the Natural Resource Management Ministerial Council (NRMMC) and the Environment Protection and Heritage Council.
The ADWG are part of the National Water Quality Management Strategy. The strategy aims to ‘achieve
sustainable use of the nation’s water resources by protecting and enhancing their quality while
maintaining economic and social development’. It provides information and tools to help communities
manage their water resources to meet current and future needs.
A regulatory impact statement (RIS) including a cost-benefi t evaluation of regulatory alternatives, was
not undertaken as part of this review. The Productivity Commission’s Offi ce of Regulation Review has
previously determined that the NHMRC is not required to undertake an RIS as the Guidelines do not have
a regulatory status. Implementation of the Guidelines by the States and Territories is at the discretion
of the State and Territory Health Department, usually in consultation with water suppliers and should
include an appropriate economic analysis prior to implementation.
1.5.1 ACKNOWLEDGMENTS
The NHMRC and NRMMC expresses gratitude to the Cooperative Research Centre for Water Quality and
Treatment for its continued support in the development of the ADWG, and in particular the Framework
for Management of Drinking Water Quality. NHMRC and NRMMC are grateful to the following people
for the excellent work they do on its behalf. The work is usually performed on an honorary basis and
in addition to their usual work commitments, and has been crucial in the continued development of the
ADWG:
NHMRC Drinking Water Review Coordinating Group
Prof Don Bursill (Chair) Cooperative Research Centre for Water Quality and Treatment
Dr David Cunliffe Department of Human Services, South Australia
Peter Scott Melbourne Water
Dr Anne Neller University of the Sunshine Coast
Alec Percival Consumers’ Health Forum
Dr John Langford Water Services Association of Australia
Brian McRae Australian Water Association
Phil Callan (Technical Secretary) National Health and Medical Research Council
Drinking Water Quality Management Working Party
Dr David Cunliffe (Chair) Department of Human Services, South Australia
Dr Martha Sinclair Monash University
Samantha Rizak Monash University
Roslyn Vulcano Department of Infrastructure, Planning and Environment, NT
Dr John Howard South Australian Water Corporation
Prof Steve Hrudey University of Alberta, Canada
Drinking Water Treatment Chemicals Working Party
Prof Michael Moore (Chair) National Research Centre for Environmental Toxicology
Dr Peter Di Marco Health Department of Western Australia
Mary Drikas South Australian Water Corporation
Dr Jim Fitzgerald Department of Human Services, South Australia
Dr Peter Mosse Gippsland Water
Colin Nicholson Sydney Water Corporation
Chapter 1 Introduction
Australian Drinking Water Guidelines 1–9
Microbial Working Party
Mike Burch (Chair) South Australian Water Corporation
Dr David Cunliffe Department of Human Services, South Australia
Glen Shaw National Research Centre for Environmental Toxicology
Dr Brenton Nicholson South Australian Water Corporation
Dr Ian Falconer Australian National University
Pesticides Working Party
Dr Les Davies (Chair) Therapeutic Goods Administration
Dr Jim Fitzgerald Department of Human Services, South Australia
Dr Brenton Nicholson South Australian Water Corporation
Protozoa Working Party
Dr David Cunliffe (Chair) Department of Human Services, South Australia
Assoc Prof Christopher Fairley Monash University
Prof Nick Ashbolt University of New South Wales
Peter Scott Melbourne Water
Dr Dennis Steffensen South Australian Water Corporation
Radiological Working Party
Dr Malcolm Cooper (Chair) Australian Radiation Protection and Nuclear Safety Agency
Philip Crouch Department of Human Services, South Australia
Richard Walker Water Corporation Western Australia
Priority Setting Group (28 January 1998)
Dr Charles Guest National Centre for Epidemiology and Population Health
Barry Sanders Agriculture and Resource Management Council
of Australia and New Zealand
Prof Don Bursill Cooperative Research Centre for Water Quality and Treatment
Annette Coburn Australian Consumers Association
Christine Cowie New South Wales Health
David Lambert National Water Quality Management Strategy Secretariat
Dr John Langford Water Services Association of Australia
Dr Peter Liehne Commonwealth Department of Health and Family Services
Dr Udomsri Low National Health and Medical Research Council
Sharon Tuffi n National Health and Medical Research Council
Others involved in the development of the Australian Drinking Water Guidelines include:
Dr Jenny Stauber Commonwealth Scientifi c and Industrial
Research Organisation
Sam Mangas Department of Human Services, South Australia
Barry Sanders Water Corporation, Western Australia
Chris Davis Australian Water Association
Dr Melita Stevens Melbourne Water