a consumer guide to accompany the australian drinking water guidelines

Natural Resource Management Ministerial Council Water Made Clear A consumer guide to accompany the Australian Drinking Water Guidelines 2004 INVESTING IN AUSTRALIA’S HEALTH Water made clear A consumer guide to accompany the Australian Drinking Water Guidelines 2004 Endorsed by NHMRC 10–11 April 2003 Natural Resource Management Ministerial Council © Australian Government 2004 Material included in this document may be freely reproduced provided that it is accompanied by an acknowledgment stating the full title of the document, the National Health and Medical Research Council and National Resource Management Ministerial Council and the date of release ISBN (print): 86496 177 ISBN (online): 86496 171 The strategic intent of the National Health and Medical Research Council (NHMRC) is to work with others for the health of all Australians, by promoting informed debate on ethics and policy, providing knowledgebased advice, fostering a high quality and internationally recognised research base, and applying research rigour to health issues NHMRC documents are prepared by panels of experts drawn from appropriate Australian academic, professional, community and government organisations NHMRC is grateful to these people for the excellent work they on its behalf The work is usually performed on an honorary basis and in addition to their usual work commitments This document is also available through the NHMRC homepage at www.nhmrc.gov.au Membership of the NHMRC Drinking Water Consumer Guide Working Group: Mr Alec Percival (Chair) Dr Anne Neller Mr Brian McRae Consumers’ Health Forum University of the Sunshine Coast Australian Water Association Secretariat Mr Phil Callan National Health and Medical Research Council Technical Writers Dr Hilary Cadman Ms Janelle Kennard Biotext Pty Ltd Biotext Pty Ltd Graphic Designer Mr Sam Highley Clarus Design Pty Limited All photos by Clarus Design unless acknowledged otherwise Contents Foreword Water made clear The essential drop Where does our drinking water come from? A limited supply of freshwater How we use our water? 7 What’s in the water? Disease and contaminants Disease-causing organisms Toxic substances Where contaminants come from? 10 11 11 11 13 The journey to the tap Keeping our water safe Protecting catchments Resting in reservoirs Treating the water Coagulation, flocculation and sedimentation Filtration Membrane filtration Disinfection 14 14 15 15 16 16 16 17 17 Checking that water is safe A proactive approach Do I need a water filter? Small water supplies Rainwater supplies Who is responsible for safe drinking water? Australian drinking water guidelines Keeping the guidelines up to date 19 20 20 21 21 22 22 23 What can I to help? Help to keep drinking water safe Treat catchments with respect Don’t tip it down the drain! Keep runoff and stormwater clean Keep your plumbing in good repair Watch out for backflow! Conserving water 24 24 24 24 24 25 25 26 Conclusion 27 Further information 28 Glossary 29 Foreword 10–11 April 2003 Australia is the driest inhabited continent, and our supply of water is not inexhaustible With Australia in the grip of the worst drought in a century, it is apparent that our freshwater supplies are indeed a precious resource To ensure that the health of all Australians is not threatened by poor quality drinking water, the National Health and Medical Research Council (NHMRC) has, for over 30 years, developed guidance on water quality for the Australian water industry The Australian Drinking Water Guidelines continue to provide vital information to all those agencies around Australia responsible for bringing you safe, good quality water It is now clear that the community also has an important role to play in the management of our water quality In developing this publication, the NHMRC seeks to make information more widely available and hopes to encourage people to gain a better understanding of those processes required for the provision of safe drinking water for the whole community This publication has been developed to highlight the many steps that water must go through before it is delivered safely to your tap, and the things that we can all to ensure that we continue to receive the highest quality drinking water Safe water is essential to sustain life — we all have a responsibility to make every effort to ensure the quality of our drinking water The NHMRC hopes that this document encourages you, as a consumer, to become more active in the management of drinking water Water is important; let’s work together to maintain this precious resource Professor Nicholas Saunders Chair, NHMRC (2000–2003) Water made clear It is easy for us to take the quality of our drinking water for granted — when we turn on the tap, we expect safe, pleasant-tasting water to flow out Long before water reaches our tap, carefully managed systems are in place protecting our water and making it safe to drink, from the water falling as rain to the point when it reaches our tap The Australian Drinking Water Guidelines (2004) give Australia’s water managers and suppliers guidance on providing good quality drinking water This booklet looks at why drinking water quality is so important, the journey our water makes to our taps, systems to ensure good water quality and how everyone can help safeguard this most precious of resources “Water is fundamental to life and health” United Nations Committee on Economic, Cultural and Social Rights (2002) The essential drop Water is essential for life Our health depends on having an adequate supply of safe water for drinking, cooking, laundry and bathing — every day The link between our water supply and disease has been recognised for thousands of years — at least since Egyptian times If our water becomes contaminated with microorganisms or chemicals, illness can result Diseasecausing microorganisms carried by water are the biggest threat to health, causing gastrointestinal upset, diarrhoea or even death In some cases, people can become ill after drinking contaminated water just once As we all depend on clean water every day, any problem with the water supply can very quickly have major consequences for an entire community Drinking water is … water intended primarily for human consumption, either directly, as supplied from the tap, or indirectly, in beverages or foods prepared with water It should contain no harmful concentrations of chemicals or pathogenic microorganisms, and ideally it should be aesthetically pleasing in regard to appearance, taste and odour Source: Australian Drinking Water Guidelines, National Health and Medical Research Council (2003) Water is all too easily wasted or contaminated We need to use it wisely and protect it Where does our drinking water come from? Our drinking water comes mainly from two sources: surface water (rainfall and its runoff into streams and rivers) and groundwater (water that has collected in underground stores or aquifers) Surface water can come from a river, lake or artificial dam Groundwater is accessed through a bore Across Australia, water suppliers access this water, treat it and distribute it to consumers A substantial number of Australian households also collect rainwater as their main source of drinking water A limited supply of freshwater The amount of water on our planet that is suitable and available for drinking is very small Only 2.5% of the total water on earth is freshwater Most of this is not available for drinking, because it is frozen in glaciers or the polar icecaps, or is unavailable in the soil Accessible freshwater is found in the atmosphere, lakes, rivers, streams, wetlands and under the surface in aquifers (groundwater) Saline water (97.5%) Ice caps and glaciers (76%) Freshwater (2.5%) World's total water Soil (23.5%) Accessible water (0.5%) Breakdown of 2.5% freshwater Across the globe, population growth, urban development and environmental degradation are putting freshwater supplies under everincreasing stress Today, out of every 10 people live in areas that are experiencing water scarcity, and nearly 50% of the world’s population is likely to face severe water shortages by 2025 Australia is particularly dry — despite occupying 5% of the world’s land area, it has only 1% of the water carried by the world’s rivers This is because Australia is flat and hot, so most of the rain that falls evaporates again before it can replenish streams, rivers and underground stores Rainfall in Australia is also very variable — our land of ‘droughts and flooding rains’ — making the supply of freshwater even more variable In the face of this unpredictable supply, Australians rely on stored water and underground supplies Large volumes of drinking water are stored in both natural and human-made reservoirs, including planned recharge of underground storages (aquifers) Australia stores more water per person than any other country — the equivalent of three Olympic swimming pools for every Australian Groundwater provides about one-fifth of Australia’s drinking water supplies Some regions use little or no groundwater, while others rely heavily on this source The Great Artesian Basin, Australia’s largest source of groundwater, provides the only reliable and continuous water supply for much of the arid outback, particularly in Queensland, New South Wales and South Australia Being difficult to access, groundwater is extremely difficult to clean up if it becomes polluted Therefore, it is vital to protect groundwater at source Atmosphere (8%) Groundwater (38%) Freshwater lakes (54%) Breakdown of 0.5% soil and surface water Solar radiation Moisture transport Precipitation Percolation Soil moistu re Water table Surfa c e run Adapted from a CSIRO Land and Water diagram Evaporation Transpiration off Groundwater to lakes and streams Deep seepage Ocean Groundwater to ocean The water cycle How we use our water? By far the biggest consumer of water in Australia is agriculture, which accounts for more than 70% of water use, mainly for irrigation Some industries are also heavy water users, such as manufacturing (approximately 3% of total water used in Australia) and the production of electricity and gas (around 8%) Approximately 8% of the water used in Australia is used in homes The water that is used in most Australian homes and gardens is of drinking water quality This means that it has been carefully managed and treated to make it safe to drink Yet only around 1% of drinking water is actually used for drinking, considerably more being used for activities like cooking, washing clothes, showering and flushing the toilet The garden takes the most drinking water, typically accounting for around 35% of consumption, although in hot, dry summers, this figure can be as high as 90% in some parts of Australia Typical use of drinking water in the home Drinking Kitchen Washing clothes Flushing toilet Showering Garden Data source: Cooperative Research Centre for Water Quality and Treatment The water we drink has been around for hundreds of millions of years It travels in a continuous cycle between the oceans, the air, the earth’s surface and underground storages (aquifers), undergoing natural cleansing as it makes this journey, but also potentially becoming contaminated Water vapour condenses to form clouds, which release water as rain, hail or snow when conditions are suitable As the water falls to earth it either moves into the soil or runs into rivers and the ocean Surface water in lakes, streams and oceans evaporates, returning moisture to the atmosphere Plants also return water to the atmosphere by taking water from the ground through their roots and releasing it from their leaves in a process known as transpiration What’s in the water? Having impurities in drinking water is not necessarily a bad thing — many constituents of normal drinking water are harmless or even desirable For example, the minerals calcium and magnesium, which can enter water from soil and rocks, are good for human health and give the water a pleasant taste Other impurities can affect the aesthetic qualities of water such as appearance, taste, smell and ‘feel’ Such impurities are not necessarily hazardous to human health In fact, the taste, smell and appearance of water is not a good guide to its safety Water that is cloudy, has a distinctive odour or has a strong taste is not necessarily harmful to health, while clear, pleasant tasting water may still contain harmful microorganisms While not all impurities are a problem, some have serious health consequences Types of impurities found in water Types of impurities Examples Microbial Bacteria Campylobacter, Legionella Viruses Hepatitis, Norwalk Protozoa Cryptosporidium, Giardia Other Cyanobacteria (blue-green algae) Physical Colour Iron, dissolved organic matter Taste and odour Geosmin, methyl isoborneol Appearance Silt, suspended particles, plankton Chemical Naturally occurring Manganese, nitrate Agricultural Atrazine, chlordane Water treatment Chlorine, fluoride Plumbing Lead, copper Industrial Poly Aromatic Hydrocarbons, mercury Radiological Naturally occurring 10 Radium, uranium Photo supplied by Cooperative Research Centre for Water Quality and Treatment In its purest form, water is simply H2O; that is, two atoms of hydrogen attached to each atom of oxygen Because water is such a good solvent, in the environment it will always contain dissolved or suspended impurities The types of impurities found in water can be divided into four groups: microbial (microorganisms), physical, chemical, and radiological Disease and contaminants A number of organisms or substances that cause human disease can contaminate water supplies The most serious of these are microorganisms They can have immediate and devastating effects on our health Some chemical contaminants also cause human disease Usually, the effects of such contaminants are only seen after long periods of exposure These two broad categories of disease-causing contaminants are examined below Disease-causing organisms Pathogenic (disease-causing) microorganisms in drinking water pose the greatest potential threat to human health Over three million people a year, many of them children under five years of age, die from waterborne and sanitation-related diseases Most of these deaths occur in the developing world, where many communities have no access to clean or treated water, or adequate sanitation Since the 1930s and 1940s water supplies in Australia have been subjected to widespread disinfection Before this time, death from water-borne diseases was much more common than it is today While the potential threat remains, in most parts of Australia, waterborne disease is controlled by good water management In some parts of Australia, water quality remains a problem, especially in some rural and indigenous communities Microorganisms include bacteria, viruses and protozoa, only a few of which cause disease However, microorganisms in human and animal faeces are responsible for most waterborne diseases In some parts of the world, waterborne diseases such as dysentery, hepatitis, cholera and typhoid cause severe, and at times fatal, diarrhoea Cryptosporidium and Giardia were recently brought to attention in Australia by the 1998 Sydney ‘water crisis’ They are protozoans — parasites that consist of a single cell Cryptosporidium and Giardia are a problem for the water supply industry because they are widespread in surface water, can survive for long periods and are difficult to treat Toxic substances Blue-green algae Cyanobacteria, better known as blue-green algae, are a health hazard because of the toxins they release Some toxins result only in a skin rash, but others are more serious, causing liver and nerve damage The toxins are released into the water and can remain even when the bacteria themselves have been removed If contamination occurs, it may not be sufficient to boil the water Boiling destroys the cells, but not all of the toxins Therefore, special treatment is required to remove the toxins from water contaminated by blue-green algae Contaminated water claims lives An outbreak of waterborne illness in Canada in 2000 highlighted the importance of protecting water supplies and the danger of waterborne microorganisms to human health Over 2000 people became ill, 65 were hospitalised and died as a result of a contamination of the water supply in Walkerton, Ontario Two major bacterial contaminants were discovered: a disease-causing strain of E coli which caused a sometimes fatal condition called ‘haemolytic uraemic syndrome’ (the same condition that occurred in the Garabaldi food poisoning incident in Adelaide); and Campylobacter, a bacteria from human and animal waste that causes gastroenteritis The two strains matched those found in cattle on farms near local water bores An inquiry found that many faults in the local water management had contributed to the outbreak, including inadequate protection of the catchment surrounding the bores, insufficient chlorination, an assumption that bores were secure water sources and inadequate training of staff operating the treatment plant Did you know that … Australia experienced the world’s worst ever algal bloom in 1991, covering more than 1000 km of the Barwon and Darling rivers in New South Wales Drinking water had to be brought into the area for residents of regional and rural towns supplied by the rivers A number of animals (but no humans) died from drinking the contaminated water Algal blooms are actually caused by bacteria (cyanobacteria), which are very widespread in the environment These organisms become a problem when nutrient levels rise This can happen when agricultural activity results in large amounts of fertilisers entering warm, slow-moving waterways 11 Photo supplied by Ted Gardner, Queensland Department of Natural Resources Pros and cons of disinfectants used for treating water Chlorine The most widely used disinfectant, chlorine generates a number of different byproducts, including trihalomethanes (THMs) It has been suggested that THMs increase the risk of cancer, but so far there is no clear scientific evidence of a risk to health from the THMs in drinking water Chlorine dioxide Generates lower levels of THMs than chlorine but is a weaker disinfectant and produces other potentially harmful byproducts such as chlorate and chlorite Chloramine Membrane filtration An alternative to filtering water through sand is to use a membrane filter, in which water is passed through tiny holes (pores) in a plastic membrane, which acts like a sieve Recent improvements in quality and performance of membrane filtration, combined with reduced costs, have made membranes competitive in many cases with conventional techniques The filtration process can produce very high quality water Disinfection Disinfection is perhaps the most important treatment process It inactivates microorganisms, rather than removing them (as filtration does) The process is most effective if the water is relatively clean; therefore, disinfection is usually the last step in water treatment Chlorine and chloramine are the disinfectants used most widely in Australia Some water supply authorities also use chlorine dioxide, ozone and/or UV irradiation All of these disinfectants have advantages and disadvantages, and all can generate byproducts that may have implications for health in the long term Although certain disinfection byproducts may pose a small risk to health the immediate health risks from not effectively disinfecting drinking water greatly outweigh the potential risk to health from the byproducts Long lasting and therefore good for maintaining a disinfectant residual, helping to ensure that microorganisms not multiply in the water in the distribution system It produces lower THM concentrations than chlorination, but does produce other byproducts such as cyanogen chloride Ozone Very effective but generates byproducts (eg bromates and aldehydes) Ozone is more expensive than chlorine and is short lived, which means that it can only be used in combination with another disinfectant UV radiation Effective disinfectant, as long as water is relatively free of suspended and dissolved particles Does not provide residual disinfection; therefore, a small dose of a persistent disinfectant such as chloramine might be added to act as a preservative during distribution Disinfection should not be compromised in attempting to control disinfection by-products (WHO, 2003) A certain level of disinfectant (known as a disinfectant residual) in the distribution system is maintained to prevent the regrowth of microorganisms before the water reaches the consumer’s tap 17 The water treatment process Source water Surface or groundwater sourced from protected catchments such as wooded and fenced areas Transfer to clarifiers Move to clarifying tanks, where the floc settles to the bottom, leaving clear water to flow into the filtration tanks Store in open reservoir Suspended material settles out; microorganisms are removed by settling out, UV radiation and natural die-off Filter Pass clear water through sand and gravel filters to remove remaining flocs and microorganisms (or pass through a microfiltration plant) Add chemicals Add chemicals such as fluoride (for dental protection) or lime (to reduce acidity) 18 Transfer to enclosed tank and add coagulant Adjust acidity levels to prevent corrosion and make disinfection more effective Add coagulant (eg alum) so that fine organic material and microorganisms will form 'flocs' (large particles) Disinfect Add disinfectant (eg chlorine) to inactivate any microorganisms that have passed through the filters Store Store in a closed tank (service reservoir) before distributing to consumers Maintain a residue of chlorine in the water to prevent infection from remaining microorganisms or those in the distribution system Checking that water is safe To check that protection and treatment processes are working, water authorities regularly monitor the quality and safety of the water they distribute State government bodies establish the level of impurities that are acceptable for a given water system The water authority must ensure that their processes are preventing these levels being exceeded Photo supplied by SA Water Corporation Monitoring water for the presence of every species of harmful microorganisms is not practical or even desirable This is because many of the tests take days or weeks, so by the time a contaminant is identified, the community has already been exposed to it Instead, monitoring is based on the use of ‘indicator organisms’ — organisms that are generally found when harmful microorganisms are present and that can be tested for quickly and easily Because human faeces are the most important source of disease-causing microorganisms in water, the tests are designed to detect particular bacteria found in the human gut Escherichia coli (E coli) is the indicator organism most often used as a measure of the microbial quality of drinking water Even where indicator organisms are used, there is a delay between contamination and a positive test that would signal the need to take action This means that tests are used as a way to check the effectiveness of treatment and other barriers, rather than as tool for managing water quality on a day-to-day basis Because of the limitations of looking for either specific microorganisms or indicator organisms, water authorities rely on other indicators that can signal a problem with the quality of the water more quickly These include: • turbidity (cloudiness) or particle counts • colour • pH (how acidic or alkaline the water is) • disinfectant residuals (a useful indicator of water quality) The benefit of these indicators is that they can be monitored ‘online’ — that is, as the water is being processed This allows serious fluctuations to be rapidly detected so that remedial action can be taken before water is distributed to customers Water authorities also use their knowledge of the catchment; for example, knowing that heavy rain might impact on water quality allows the problem to be monitored and addressed 19 A proactive approach The current edition of the Australian Drinking Water Guidelines emphasises the importance of preventive management of drinking water quality This approach focuses on identifying and managing risks in a proactive way, rather than simply reacting when problems arise The first step is to look systematically at all the potential hazards to the water supply from the catchment to the consumer’s tap (ie what might happen and how) A hazard could be anything from animal wastes being washed into the source water during heavy rainfall, to insufficient disinfectant being added during treatment Once the hazards are identified, the next step is to assess the risk from each hazard, by estimating the likelihood that the event will happen and what the consequences would be if it did The final stage is to ensure that existing preventive measures are sufficient to control the hazards and to improve or replace such measures if necessary The current guidelines include a framework that can be used to apply this risk management approach to water supply systems of any size The framework is flexible and can easily be adapted to suit local conditions — an aspect that is particularly useful in Australia because of the wide variation in water suppliers Through risk management, all stakeholders (including consumers) can become involved in water quality issues in a cooperative and coordinated way, with a better understanding of everyone’s roles and responsibilities Do I need a water filter? For homes attached to a mains water supply, a water treatment device is probably not necessary, because the water supplier is responsible for providing water that is safe to drink and of good aesthetic quality However, consumers may choose to use a home treatment device, and there are many products on the market There are two primary reasons why consumers may choose to have a home water filter — for aesthetic reasons to improve taste or odour, and for health reasons to protect against microorganisms Different types of filters are designed to remove different contaminants, so it is important to select the correct type of filter for the right purpose Most are ‘point-of use’ devices that simply treat water where it is used, such as at the kitchen sink The advantage of this approach is that only water used for drinking or cooking is treated, so it is much cheaper than treating the entire water supply to the home with a point-of-entry device Whatever sort of device is used, it is important to maintain it properly, because home water treatment devices can be a health hazard For example, a water filter provides an excellent environment for bacteria to grow if it is not used properly Bottled water is subject to different water quality requirements than drinking water, so water delivered in bottles is not necessarily subject to the same treatment, storage and delivery requirements as drinking water out of the tap 20 Small water supplies Some small communities in Australia use water that is untreated or only partially treated The Australian Drinking Water Guidelines include advice for small water supplies (those serving less than about 1000 people), where it may be difficult to follow the general guidelines because of the high cost involved In the case of small supplies, many of the general principles outlined above still apply For example, water quality should be checked regularly through a monitoring program, and the catchment must be protected and kept as clean as possible — whether this is the catchment of a local river, the area around a bore or simply a person’s rooftop A dead animal or bird in the area surrounding a bore, for example, can pose a potential health risk Many small communities rely on bore water If such groundwater is in confined or deep aquifers, it will generally be free of pathogenic microorganisms As long as it is protected during transport from the aquifer to consumers it should remain free of harmful microorganisms Indigenous communities and Australians living in rural and remote communities are those most likely to those obtain their water from small supplies For example, Tasmania has many small local government water supply systems in remote areas These small supplies tend to experience problems with microbiological water quality, particularly when raw water is of poor quality or when catchments are affected by events like flooding Rainwater supplies For homes using rainwater, there is often no treatment of water after it collects in tanks from roof runoff ‘First-flush’ devices, which prevent the initial roof-cleaning wash of water (20–25 L) from entering tanks, improve the quality of the water collected from the roof These devices are highly recommended for anyone using rainwater for drinking Alternative solution for small supplies Microfiltration is a type of membrane filtration that provides an alternative to conventional filtration, passing the water through much smaller pores (which act like a very fine sieve) The process requires relatively little space, involves no chemical pretreatment, is easily automated and needs little maintenance This technology is becoming increasingly popular for small-scale treatment plants For example, Western Water, in Victoria, uses microfiltration at its Romsey water treatment plant Microfiltration was also the method chosen for the water supply in Port Douglas Many of the residents of this north Queensland town depend on tourism for a living, so protecting the environment was an important factor in deciding what type of treatment to use The town’s water originates from rainforest runoff, picking up not only leaves and soil from the forest, but also contributions from birds, feral pigs and a host of other wildlife Given a choice between microfiltration and chemical treatments like chlorine, chloramination or ozone (all of which would provide clean, safe, drinking water), residents opted for the filtration process, even though it was the most expensive, because it would have the least impact on the environment For those with a rainwater supply, it is important to check regularly to ensure that first-flush devices are working properly It is also important to keep the roof catchment clean — bird droppings, peeling paint and dirt on the roof are the biggest sources of contamination Guttering should be cleared regularly and overhanging branches should be kept to a minimum, because they can be a source of debris and allow birds and small animals access to the roof If contamination of a private supply is suspected, the state health department can provide advice on testing the water 21 Who is responsible for safe drinking water? The responsibility for delivering safe drinking water lies with drinking water suppliers, but they need to work in partnership with other agencies, such as health departments and catchment managers Often a health department will take on a regulatory role, helping to establish the requirements for monitoring drinking water, communicating the results and planning for emergencies Australian Drinking Water Guidelines Since 1972, Australia has produced its own drinking water guidelines, appropriate for local conditions The current Australian Drinking Water Guidelines were developed by the National Health and Medical Research Council (NHMRC) with support from the Natural Resource Management Ministerial Council (NRMMC) They combine the results of local and international research with appropriate information from other sources, such as the World Health Organization The guidelines apply to any water intended for drinking, wherever it comes from and wherever it is used, apart from bottled or packaged water (which is the responsibility of Food Standards Australia New Zealand) Although the Australian Drinking Water Guidelines are not legally enforceable, they provide recommended guideline values for constituents that affect water quality and safety, which state and territory governments use to set regulatory standards or license conditions The main focus of Australia’s guidelines is on safeguarding human health; however, they also cover the aesthetic qualities of water (how the water looks, smells, tastes and ‘feels’) Drinking water will inevitably contain impurities; what is important is to ensure that any impurities not pose an unacceptable risk to health or make the water unpleasant to drink For water quality characteristics that could be harmful to health, the Australian Drinking Water Guidelines give a health-related guideline value This value is the concentration that, based on current knowledge, would not result in any significant health risk to a person who drank the water throughout their lifetime For water quality characteristics that could affect factors such as colour, odour, cloudiness and taste, the guidelines give an aesthetic guideline value The aesthetic quality of water is important because it affects what people experience when they drink or use water and how they rate its quality For example, the taste of drinking water can be affected by temperature, dissolved material and how acidic or alkaline the water is The current Australian Drinking Water Guidelines cover a range of topics, including management of water supply systems, water quality (microbiological, physical, chemical and radiological), monitoring, community consultation and special issues associated with supply to small communities 22 For most water quality characteristics, there is a grey area between what is clearly safe and what is clearly unsafe; therefore, the guidelines err on the side of safety, setting a value that is generally 10 to 100 times lower than the level considered safe What this means is that if a chemical was thought to be safe when present at a level of 50 mg/L, the guideline value would set be set somewhere between 0.5 and mg/L Therefore, with the exception of microbial contaminants, occasional results in excess of the health guideline value generally not pose an immediate concern for public health Normally, a water utility will take measures to minimise the occurrence of such results, in consultation with the local health agency Copper is an example of a chemical for which the Australian Drinking Water Guidelines set two values: a health-related value of not more than mg/L and an aesthetic-related value of not more than mg/L The aesthetic-related guideline value is the lower of the two, because copper in drinking water affects the taste at levels that are not harmful to health Keeping the guidelines up to date The drinking water guidelines are not static — they are continuously updated to keep abreast of evolving scientific knowledge on water quality Each year, in consultation with the community and health, water and resource management agencies, sections of the guidelines are selected for revision A section might be revised because new research has become available, or because the section simply hasn’t been reviewed for some time Photo supplied by Ted Gardner, Queensland Department of Natural Resources The guidelines have also been revised and reorganised to reflect the fairly dramatic changes that have occurred in the Australian water supply industry in recent years, as more agencies have become involved and responsibilities have diverged The guidelines also tend to become more stringent as new research establishes links between contaminants and adverse health effects The continued revision of the Australian Drinking Water Guidelines is a collaborative effort between the NHMRC and a wide range of experts in Australia and overseas In 1998, the Drinking Water Review Coordinating Group was formed to manage the ‘rolling revision’ of the guidelines This committee is supported by a number of specialised working parties that are responsible for the revision of specific aspects of the guidelines In developing the guidelines, the NHMRC draws on expertise in universities, the water industry, community organisations, health authorities and water resource departments National Resource Management Ministerial Council 23 What can I to help? Help to keep drinking water safe There are a number of ways in which everyone can help protect our safe drinking water Treat catchments with respect Many catchment areas are specifically signposted as such Always follow the advice on such signs and not pollute these areas Remember that many activities — from trail-bike riding to camping — can affect the catchment Check with your local water authority to find out what activities are permitted in the catchment Don’t tip it down the drain! Never put chemicals and solvents down the drain or toilet If organic solvents in products such as paint removers and strippers reach sewage treatment plants they can destroy the beneficial bacteria used to purify wastewater which may eventually become a source of drinking water for other communities Solvents can also contaminate water sources, making it more difficult and expensive to treat water to a quality suitable for drinking A better way to dispose of such products is to take them to your local hazardous waste collection depot For example, Sydney Water runs household chemical collection days for residents to dispose of any chemicals they are concerned about, such as pesticides, herbicides, fungicides and weed killers Remember — the drain is for rain! Keep runoff and stormwater clean Stormwater (the runoff from rainfall that eventually ends up in rivers, streams and the oceans) is a major source of contamination for ground and surface water Never litter — things thrown onto the street often end up in stormwater Commercial fertilisers applied to gardens also wash off — up to half of the nitrogen from fertiliser on lawns ends up polluting water bodies Alternatives are to use a natural fertiliser, such as compost, or, better still, replace lawns with native plants and shrubs, which not only reduces the need for watering and fertilisers, but provides habitat and food for native animals 24 Keep your plumbing in good repair The quality of the water beyond the water meter is the householder’s responsibility You should ensure that you use qualified plumbers and use only suitable materials for pipes Leaky taps and pipes are a major source of wasted water, so it pays to keep them working well Watch out for backflow! Be aware that under certain circumstances, water can be drawn from your property back into the mains distribution system Usually, the mains system is pressurised to ensure that this doesn’t happen However, in the event of the pressure dropping (eg due to a broken mains or water being pumped from the main water supply during a fire), backflow can happen This type of problem is particularly relevant to industrial and commercial water users, who must comply with regulations for fitting devices that prevent backflow Household water users should also be aware of possible contamination sources For example, never leave a hose in a swimming pool or pond unattended as the water can be siphoned out in the event of a pressure drop If you have a permanently connected sprinkler system or use a spray fertiliser or weed killer connected to a hose, you will probably need a backflow prevention device The device should be installed by an accredited backflow prevention plumber Check with your local authority if you are unsure 25 Conserving water Whenever we use more water than we need to around the house, we are using up a precious resource, wasting money and energy, and generating unnecessary amounts of wastewater The water that goes down the drain ends up in the sewerage system; excessive consumption means more expenditure and energy used for treatment of sewage Using less water around the house means lower water and energy bills (where hot water use is reduced), and less stress on the environment, which ultimately contributes to maintaining or improving water quality Most households can find cheap ways to reduce their water use, and can often recoup the cost in water and energy savings within a relatively short period Ideas for reducing water use include: • reducing time spent in the shower • switching to water-efficient appliances such as efficient shower heads and taps, dual flush toilets and front-loading washing machines; for example an ‘AAA’ rated water-efficient shower-head is cheap and can reduce indoor household water consumption by 20%* • installing a rainwater tank to collect the water falling on the roof that otherwise may be channelled straight to the stormwater drain (you will need to check with your local council to ensure rainwater can be harvested for household use) • washing the car on the lawn (or using a professional car wash facility where water is used efficiently) • cleaning paths and driveways by sweeping them, never by hosing them down Because water used in the garden or in toilets does not need to be of such high quality as drinking water, one approach to reducing the cost and energy used in treating water is to have a dual reticulation system The system provides two grades of water — one suitable for drinking, the other for non-potable uses like watering the garden Rouse Hill, in Sydney, was the first development in Australia to have a dual water system supplying drinking and recycled water An alternative to dual reticulation is to use rainwater for toilet flushing and for outdoor use In the past, collection of rainwater in urban areas was discouraged because of concerns about contamination with harmful microorganisms or the breeding of mosquitoes, but research has shown that these concerns can be well managed If you are interested in this approach, check with your local council before investing in any equipment * More information on the 5A rating water-efficiency scheme is available at www.wsaa.asn.au 26 A thirsty country While two thirds of all the people on earth use less than 60 litres of water a day the average Australian uses more than twice that amount during a single shower In fact, Australians are among the biggest users of water in the world, especially around the home Source: Melbourne Water – conservewater.mel bournewater.com.au/html/driest.htm Water-sensitive design Figtree Place, a community housing project of 27 units in Newcastle, New South Wales, is designed to make efficient use of water The development includes a number of water management features: • All rainwater falling on the units is diverted to underground tanks that supply the hot water and toilet systems (the water is of sufficiently high quality to meet the Australian guidelines for drinking water) • Overflow from rainwater tanks is diverted into gravel-filled trenches, and is eventually used to replenish groundwater, together with water from driveways and paved areas • Groundwater drawn from a bore is used for irrigating open spaces, including household gardens • Surplus groundwater is used to wash vehicles at the adjacent bus depot Through these simple strategies, Figtree Place and the adjacent bus depot have reduced their combined mains water use by 77%, and stormwater runoff from the housing development has been almost completely eliminated Further information on water-sensitive design and urban stormwater management can be found on the websites of the University of Newcastle (www.newcastle.edu.au) or the Environment Protection Authority (www.epa.nsw.gov.au) Conclusion This publication has been prepared as a consumer’s guide to the Australian Drinking Water Guidelines, to encourage people outside the water industry to gain a better understanding of how water is collected, treated and delivered to the tap If you have questions about the quality of your drinking water, your local government, state health department or local water authority will be able to provide you with further advice It is important that we all take responsibility for the management of our water resources and work together with those responsible for the provision of drinking water to ensure its use is sustainable 27 Further information This publication has been prepared as a consumer’s guide to accompany the Australian Drinking Water Guidelines Copies of the Australian Drinking Water Guidelines are available on the NHMRC website and through AusInfo government bookshops Additional information Australian resources Publications • Australian Drinking Water Guidelines, National Health and Medical Research Council (www.nhmrc.gov.au/publications/synopses/eh19syn.htm) • A Consumer’s Guide to Drinking Water, CRC for Water Quality and Treatment (www.waterquality.crc.org.au) • Australian Water Resources Assessment 2000 — Surface and Groundwater availability and quality (www.nlwra.gov.au) • How Safe is Your Water Supply?, Choice, Australian Consumers’ Association (www.choice.com.au/articles/a100218p1.htm) • How to Save Water and Money, Choice, Australian Consumers’ Association (www.choice.com.au/articles/a100711p1.htm) • Salinity, CSIRO Land and Water (www.clw.csiro.au/issues/salinity) • Waterwise House & Garden, Allan Windust, Landlinks Press, Australia • Your Private Drinking Water Supply (www.dhs.vic.gov.au/phd/9911054/) Organisations • Australian Water Association (www.awa.asn.au) • Cooperative Research Centre for Catchment Hydrology (www.catchment.crc.org.au) • Cooperative Research Centre for Water Quality and Treatment (www.waterquality.crc.org.au) • CSIRO Land and Water (www.clw.csiro.au/issues/salinity) • Environment Australia (www.ea.gov.au) • National Health and Medical Research Council (NHMRC) (www.nhmrc.gov.au) • savewater.com.au (www.savewater.com.au) • Water Watch Australia (www.waterwatch.org.au) • Water Services Association of Australia (www.wsaa.asn.au) International resources • Guidelines for Drinking Water Quality — World Health Organization (www.who.int/water_sanitation_health/GDWQ/index.html) • Guidelines for Canadian Drinking Water — Health Canada (www.hc-sc.gc.ca/ehp/ehd/catalogue/bch_pubs/dwsixth.htm) • Water on Tap: A Consumer’s Guide to the Nation’s Drinking Water — United States Environmental Protection Agency (www.epa.gov/safewater/wot/wot.html) • The American Water Works Association (AWWA) has produced educational information on drinking water, suitable for water authorities, community groups, schools, youth organisations and the media (www.awwa.org/advocacy/bluethumb/index.cfm) 28 Glossary ADWG Australian Drinking Water Guidelines, published by the National Health and Medical Research Council (NHMRC) Aquifer an underground layer of permeable rock, sand or gravel that carries water, allowing it free passage through pore space Bacteria Single-celled, microscopic living organisms found almost everywhere Most are harmless Campylobacter a group of bacteria that are a major cause of diarrhoeal illness catchment area of land that collects rainfall and contributes to surface water (streams, rivers, wetlands) or to groundwater coagulation clumping together of very fine particles into larger particles using chemicals (coagulants) that neutralise the electrical charges of the fine particles and destabilise the particles Cryptosporidium microorganism commonly found in lakes and rivers that is highly resistant to disinfection; has caused several large outbreaks of gastrointestinal illness and can cause severe and persistent symptoms, particularly in people with weakened immune systems cyanobacteria bacteria commonly known as ‘bluegreen algae’, which secrete toxins that are harmful to human health disinfectant an oxidising agent (eg chlorine, chlorine dioxide, chloramines and ozone) that is added to water in any part of the treatment or distribution process and is intended to kill or inactivate diseasecausing microorganisms filtration process in which particulate matter in water is removed by passage through porous media disinfection the process designed to kill most microorganisms in water, including essentially all disease-causing bacteria Giardia lamblia a protozoan frequently found in rivers and lakes, which can cause a severe gastrointestinal disease called giardiasis if ingested disinfection byproduct product of reactions between disinfectants, particularly chlorine, and naturally occurring organic material distribution system a network of pipes leading from a treatment plant to customers’ plumbing systems drinking water water intended primarily for human consumption (also known as potable water) drinking water supplier an organisation, agency or company that has responsibility and authority for treating and/or supplying drinking water drinking water supply system all aspects from the point of collection of water to the consumer (includes catchments, groundwater systems, surface water, storage reservoirs and intakes, treatment systems, service reservoirs and distribution systems) enteric pathogen pathogen (disease-causing organism) found in the gut Escherichia coli (E coli) bacterium found in the gut, used as an indicator that water has been contaminated with faeces flocculation process in which small particles clump together through gentle stirring groundwater water contained in underground stores guideline value the concentration or measure of a water quality characteristic that, based on present knowledge, either does not result in any significant risk to the health of the consumer (healthrelated guideline value), or is associated with good quality water (aesthetic guideline value) hazard a biological, chemical, physical or radiological agent that has the potential to cause harm hazardous event an incident or situation that can lead to the presence of a hazard (what can happen and how) indicator organisms microorganisms whose presence is indicative of pollution or of more harmful microorganisms (eg Escherichia coli indicate the presence of diseasecausing bacteria) microorganism An organism too small to be seen without the aid of a microscope 29 Glossary (continued) multiple barriers use of more than one preventive measure as a barrier against hazards reservoir any natural or artificial holding area used to store, regulate or control water pathogen a disease-causing organism (eg bacteria, viruses and protozoa) risk the likelihood of a hazard causing harm in exposed populations in a specified timeframe, including the magnitude of that harm pH an expression of the intensity of the alkaline or acid condition of a liquid (natural waters usually have a pH between 6.5 and 8.5) preventive measure any planned action, activity or process that is used to prevent hazards from happening or reduce them to acceptable levels Protozoa a group of single-celled animals 30 service reservoir/tank a storage for drinking water, generally within the distribution system, used to meet fluctuating demands, accommodate emergency requirements or equalise operating pressures source water water in its natural state, before any treatment to make it suitable for drinking storage reservoir a natural or artificial impoundment used to hold water before its treatment and distribution surface water all water naturally open to the atmosphere (eg rivers, streams, lakes and reservoirs) Virus An infectious agent of very small size and simple structure, that can only replicate within a living cell A virus consists of a core of nucleic acid (either DNA or RNA) within a protein shell The National Health and Medical Research Council The National Health and Medical Research Council (NHMRC) is a statutory authority within the portfolio of the Commonwealth Minister for Health and Ageing, established by the National Health and Medical Research Council Act 1992 The NHMRC advises the Australian Community and Commonwealth, State and Territory Governments on standards of individual and public health, and supports research to improve those standards The NHMRC advises the Commonwealth Government on the funding of medical and public health research and training in Australia and supports many of the medical advances made by Australians The NHMRC also develops guidelines and standards for the ethical conduct of health and medical research The Council comprises nominees of Commonwealth, State and Territory health authorities, professional and scientific colleges and associations, unions, universities, business, consumer groups, welfare organisations, conservation groups and the Aboriginal and Torres Strait Islander Commission The Council meets four times a year to consider and make decisions on reports prepared by Committees and working parties following wide consultation on the issue under consideration A regular publishing program ensures that Council’s recommendations are widely available to governments, the community, scientific, industrial and educational groups A list of current publications is available on our Internet site at: http://www.nhmrc.gov.au ... (www.nhmrc.gov.au) • savewater.com.au (www.savewater.com.au) • Water Watch Australia (www.waterwatch.org.au) • Water Services Association of Australia (www.wsaa.asn.au) International resources • Guidelines. .. risk to health or make the water unpleasant to drink For water quality characteristics that could be harmful to health, the Australian Drinking Water Guidelines give a health-related guideline value... pleasing in regard to appearance, taste and odour Source: Australian Drinking Water Guidelines, National Health and Medical Research Council (2003) Water is all too easily wasted or contaminated