a consumer guide to accompany the australian drinking water guidelines

I N V E S T I N G I N A U S T R A L I A ’ S H E A L T H
Water Made Clear
A consumer guide to accompany the
Australian Drinking Water Guidelines 2004
Natural Resource Management Ministerial Council
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): 1 86496 177 5

ISBN (online): 1 86496 171 6
e 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 knowledge-
based 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
do on its behalf. e work is usually performed on an honorary basis and in
addition to their usual work commitments.
is 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) Consumers’ Health Forum
Dr Anne Neller University of the Sunshine Coast
Mr Brian McRae Australian Water Association
Secretariat
Mr Phil Callan National Health and Medical Research Council
Technical Writers
Dr Hilary Cadman Biotext Pty Ltd
Ms Janelle Kennard Biotext Pty Ltd
Graphic Designer
Mr Sam Highley Clarus Design Pty Limited
All photos by Clarus Design unless acknowledged otherwise.
5
Contents
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Water made clear
. . . . . . . . . . . . . . . . . . . . . . . . . . 7
e essential drop
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Where does our drinking water come from? . . . . . 7
A limited supply of freshwater
. . . . . . . . . . . . . . . . . . 8
How do we use our water? . . . . . . . . . . . . . . . . . . . . . .
9
What’s in the water? . . . . . . . . . . . . . . . . . . . . . . . 10
Disease and contaminants . . . . . . . . . . . . . . . . . . . . . 11
Disease-causing organisms
. . . . . . . . . . . . . . . . . . . . . . . . . 11
Toxic substances . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Where do contaminants come from?

. . . . . . . . . . . . . . 13
e journey to the tap . . . . . . . . . . . . . . . . . . . . .
14
Keeping our water safe . . . . . . . . . . . . . . . . . . . . . . . . .
14
Protecting catchments . . . . . . . . . . . . . . . . . . . . . . . . .
15
Resting in reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Treating the water . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
16
Coagulation, flocculation and sedimentation
. . . . . . . 16
Filtration
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Membrane filtration
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Disinfection
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Checking that water is safe . . . . . . . . . . . . . . . . .
19
A proactive approach . . . . . . . . . . . . . . . . . . . . . . . . . .
20
Do I need a water filter? . . . . . . . . . . . . . . . . . . . . . . . .
20
Small water supplies . . . . . . . . . . . . . . . . . . . . . . . . . . .
21
Rainwater supplies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Who is responsible for safe drinking water? . . . . .
22
Australian drinking water guidelines

. . . . . . . . . . . 22
Keeping the guidelines up to date
. . . . . . . . . . . . . . . . . . 23
What can I do to help? . . . . . . . . . . . . . . . . . . . . .
24
Help to keep drinking water safe . . . . . . . . . . . . . . . 24
Treat catchments with respect
. . . . . . . . . . . . . . . . . . . . . 24
Don’t tip it down the drain!
. . . . . . . . . . . . . . . . . . . . . . . . 24
Keep runoff and stormwater clean
. . . . . . . . . . . . . . . . . 24
Keep your plumbing in good repair
. . . . . . . . . . . . . . . . 25
Watch out for backflow!
. . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Conserving water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
26
Conclusion
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Further information . . . . . . . . . . . . . . . . . . . . . . .
28
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
29
6
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. e 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.
is 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 do 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. e 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)
7
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.
e Australian Drinking Water Guidelines (2004) give Australia’s water
managers and suppliers guidance on providing good quality drinking water.
is 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.
e 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.
e 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. Disease-
causing 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.
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.
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 fundamental to life and health”
United Nations Committee on Economic, Cultural and
Social Rights (2002)
8
A limited supply of freshwater
e 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).
Across the globe, population growth, urban development and
environmental degradation are putting freshwater supplies under ever-
increasing stress. Today, 4 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. is 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. e 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. erefore, it is vital to protect groundwater at source.
Saline water (97.5%)
World's total water Breakdown of 2.5% freshwater
Breakdown of 0.5%
soil and surface water
Ice caps and

glaciers (76%)
Freshwater
lakes (54%)
Groundwater
(38%)
Atmosphere (8%)
So
il
(23.5%)
Accessible water (0.5%)Freshwater (2.5%)

9
How do 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.
e water that is used in most Australian homes and gardens is of drinking
water quality. is 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. e 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.
e water cycle
e 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.
Typical use of drinking water in
the home
Deep seepage
Groundwater to ocean
Transpiration
Surf
ace runof
f

Ocean
Groundwater to lakes and streams
Moisture transport
Evaporation
Precipitation
Percolation
So
il m
o
isture
Wa
ter
tabl
e
Solar
radiation
Drinking
Kitche
n
Wa
shing clothes
Flushing toile
t
Showering
Garden
Data source: Cooperative Research Centre for Water Quality and Treatment Adapted from a CSIRO Land and Water diagram
10
What’s in the water?
In its purest form, water is simply H
2

O; 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.
e types of impurities found in water can be divided into four groups:
microbial (microorganisms), physical, chemical, and radiological.
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 Radium, uranium
Photo supplied by Cooperative Research Centre for Water Quality and Treatment
11
Disease and contaminants
A number of organisms or substances that cause human disease can
contaminate water supplies. e most serious of these are microorganisms.
ey 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. ese 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’. ey 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. e 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. erefore,
special treatment is required to remove the toxins from water contaminated
by blue-green algae.
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. ese organisms become
a problem when nutrient levels rise. is can

happen when agricultural activity results in
large amounts of fertilisers entering warm,
slow-moving waterways.
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 7
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. e
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.

12
Fertilisers and pesticides from
agriculture and forestry
Hazardous wastes from industry
Livestock waste from farming
Human waste from urban
development
Runoff from mining and
quarrying
Leaks from landfill sites
Substances that can pollute drinking water sources
Photo: Getty Images
13
Chemicals
Pathogenic microorganisms have fairly immediate effects but health effects
from potentially harmful chemical and radioactive contaminants in drinking
water become evident only after long exposure (typically many years). For
example, low levels of arsenic in drinking water might increase the incidence of
skin, lung or bladder cancer, in a population that had been drinking the water
for many years.
Chemicals of concern for drinking water include some naturally occurring
chemicals, such as nitrate, selenium and uranium; agricultural chemicals
such as pesticides and fertilisers; and the chemical byproducts formed
when water is treated with a disinfectant (these disinfection byproducts
are discussed in detail below in the section on water treatment). However,
the amount of these chemicals in our drinking water is generally very
small — much lower than the levels that would be considered harmful to
health. Indeed, we are exposed to higher levels of these chemicals in our
environment and our food (though they are well below what is considered a
safe level).

Radioactive contaminants
e health effect most strongly associated with radioactive contaminants is
cancer. Extremely low levels of radiation are a naturally occurring characteristic
of water in our environment. Drinking water is likely to contribute only a very
small proportion of a person’s overall natural exposure to radiation.
Where do contaminants come from?
Microbiological, physical, chemical and radiological materials can all be found
naturally in water in the environment, and can also result from a range of human
activities. For example, inadequately treated sewage or animal wastes from
agriculture can contaminate surface and groundwater with microorganisms.
Agriculture, industry, household activities and runoff from roads can contam-
inate water with chemicals such as nitrates, pesticides, fertilisers, heavy metals,
solvents and volatile organic compounds, such as petroleum products.
Certain chemicals are added to water as part of the treatment process. For
example, aluminium sulfate is used to help remove particles from water,
chlorine is added as a disinfectant and fluoride is often added to improve
dental health. e Australian Drinking Water Guidelines specify the safe,
tolerable level of these additives. Water suppliers ensure that chemicals that
are added during treatment and may remain in the water when it reaches
the consumer do not exceed these levels.
A further source of chemicals can be household plumbing that contains
copper or lead. ese chemicals can leach into drinking water on its way to
the tap. Consumers who are concerned about their household plumbing
should discuss this matter with their local health or water authority.
Australia’s drinking water supplies are carefully managed to ensure that
dangerous contaminants either do not get into the untreated water, or are
reduced to safe levels long before the water reaches our taps.
14
e journey to the tap
e following sections track the journey that our water takes from rainfall to

the tap. ey outline how the safety of our water is ensured along the way.
In Australia, the way our water is treated and managed depends on where
we live. Our population is generally clustered in large cities along the coast,
vast areas of Australia are only very sparsely populated. As a consequence,
there is a huge variation in scale in water-delivery systems. Some water
authorities supply populations of more than a million (Sydney Water
services four million people in the Sydney region, for example) while many
others service as few as several thousand (such as AQWEST, in Bunbury,
Western Australia, servicing around 34,000 people). In addition, some local
governments run small systems that supply drinking water to as few as 20
people, while about one in six Australian homes use rainwater collected on
roof catchments.
Because large metropolitan systems supply the majority of Australians with
their water, such systems are used in the following section to illustrate the
practices that keep our water safe. Many of these practices also apply to the
smaller distribution systems. Particular issues for smaller systems are outlined
in a separate section.
Keeping our water safe
We keep our drinking water safe through a combination of protection and
treatment, aimed at ensuring that water is safe for human consumption,
pleasant to drink and reasonably priced.
No single intervention is sufficient to deliver safe, high quality drinking
water to consumers. Ideally, the primary focus of the water authority is on
preventing the water from becoming contaminated; that is, protecting the
water. e idea is that the combined effects of multiple barriers prevent
and/or reduce hazards to tolerable levels. In the event that one barrier fails,
other barriers should be sufficient (at least in the short term) to compensate.
Traditional barriers include:
• protecting the catchments and source water
• holding water in protected reservoirs or storage

• treatment
• disinfection
• protecting the distribution system
• maintenance of the distribution system.
Photo supplied by Cooperative Research Centre for Water Quality and Treatment
15
Protecting catchments
e condition of the catchment — the area over which rainwater is caught
and drains into a water supply — is probably the most important factor
influencing the quality of water. It also determines how much treatment is
needed before the water is safe to drink. Water drawn from a pristine natural
catchment will be of higher quality and need less treatment than water
that has flowed through a heavily used urban or agricultural area. Where
practical, catchments can be protected by excluding industry, agriculture
and urban development and by limiting human access to the area. Even
where land uses are permitted within the catchment, the condition of the
riparian (river or stream) corridors can have a great influence on the quality
of the water supplies.
Rainfall patterns over the catchment also affect the quantity and quality
of water flowing into supplies. Experience has shown that unusually heavy
rainfall can wash large amounts of contaminants from the catchment into
storage reservoirs. It can also mix water and sediment within reservoirs,
stirring up microbes and other matter that had previously settled.
e Australian Drinking Water Guidelines provide information for water
authorities on how to set out careful catchment management plans. e
plans identify possible risks and hazards, such as grazing livestock or sudden
heavy rainfall, which could cause contamination. Appropriate responses
are incorporated into management plans, to ensure that the water supply
remains safe, despite these possible hazards. For example, following heavy
rainfall, authorities could select water from an alternative source, or adjust

the water treatment to cope with the influx of contaminants.
Resting in reservoirs
Water running off the catchment area is stored in protected reservoirs
before being drawn off for treatment and distribution. Water may remain in
a reservoir for a month or two—or up to several years—before it is drawn
off for treatment and use. is allows many contaminants to settle out of
the water and many microorganisms to be destroyed by natural ultraviolet
(UV) radiation from the sun. Storage also allows water to be drawn off
from different levels, so that the highest quality water can be selected for
treatment.
16
Treating the water
Water treatment mainly involves the removal of sediments and
contaminants, followed by disinfection to kill potentially harmful
microorganisms. Treatment can also include measures to improve aesthetic
qualities such as the colour, taste and smell of drinking water. e choice
of treatment depends on where the water comes from, what type of
contaminants might be present and the cost of the treatment compared to
the savings made through the prevention of diseases in the community.
e water treatment applied most widely in Australia is a combination of
coagulation, flocculation, sedimentation and filtration. It is based on the
fairly simple technologies that were developed in the 19
th
century and
have been refined to require less time, space and cost and to operate more
efficiently and effectively. However, water treatment technology is beginning
to change in response to technical advances, better understanding of the
contaminants present in drinking water and their health risks, rising public
expectations and the need to balance cost against effectiveness.
Coagulation, flocculation and sedimentation

Fine particles like clay, silt and algae do not settle out on standing; instead
they are removed using a chemical called a coagulant or flocculant. e
coagulant binds the particles into large clumps (flocs) that either settle
out or can be removed by filtration. Commonly used coagulants include
aluminium sulfate (alum), polymers and iron salts. Together, coagulation,
flocculation and sedimentation remove more than 99% of bacteria and
viruses, organic matter from soil and vegetation, and some chemicals.
ese processes do not completely remove dissolved material, which can
include toxins and compounds that affect taste and smell, and organic
matter that encourages growth of microorganisms and formation of
disinfection byproducts. An additional mechanical or chemical purification
step, such as treating water with activated carbon, can be used to remove
this type of contaminant.
Filtration
e passage of water through a bed of fine particles (eg sand and gravel)
removes fine suspended solids and larger microorganisms. Filtration can
be used alone (particularly if the source water does not contain a lot of
suspended material) or in combination with coagulation and flocculation.
Carbon added to filter beds can remove objectionable tastes or odours. e
carbon works through adsorption, drawing contaminants out like a sponge
or magnet, rather than physically filtering them out.
A novel approach to water
treatment
Cost effective management of dissolved
organic carbon (DOC) in water is one of the
key challenges facing today’s water treatment
industry. At best, traditional treatment processes
generally remove only about half of the organic
matter in water. e material that remains
can have a major impact on coagulation,

maintenance of disinfection residual and the
formation of chemical byproducts. It can
also produce undesirable taste, odour and
appearance of the water.
After many years of research, the Australian
Water Quality Centre and the South Australian
Water Corporation, in collaboration with CSIRO
and Orica, has developed a new resin, which
could be the answer to this problem. MIEX®
DOC resin is a simple to use, cost-effective
and environmentally friendly way to improve
management of water quality. e resin removes
organic material by absorption and is then
regenerated using salt. No chemicals are added to
water during the process, and because the resin
can be recycled, it is cost effective.
e first commercially operating water treatment
plant in the world that incorporates MIEX® DOC
resin technology is located at Mount Pleasant in
South Australia, and provides water to Mount
Pleasant, Eden Valley.
Photo supplied by Ted Gardner, Queensland Department of Natural Resources
17
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. e 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). e 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.
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.
Pros and cons of disinfectants
used for treating water
Chlorine
e 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
Long lasting and therefore good for
maintaining a disinfectant residual, helping to
ensure that microorganisms do 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.
Photo supplied by Ted Gardner, Queensland Department of Natural Resources
18
Source water
Surface or groundwate
r sourced
fr

om protected catchments such as
wooded and fenced areas
Store in open reservoir
Suspended materia
l settles out;
microorganisms are removed
by settling out, UV radiation
and natural die-off
.
Transfer to enclosed tank
and add coagulan
t
Adjust acidity levels t
o
prevent corrosion and make
disinfection more effective.
Add coagulant (eg alum) s
o
that fine organic material and

microorganisms will form
'flocs' (large particles).
Transfer to clarifier
s
Move to clarifying tanks,
wher
e the floc settles to the
bott
om, leaving clear water to
fl

ow into the filtration tanks.
Filter
Pass clear water through sand and

grav
el filters to remove remaining
flocs and microorganisms (or pass
through a microfiltration plant).
Disinfec
t
Add disinfectant (eg
chlorine) to inactivate any
microorganisms that have
passed through the f
ilters.
Add chemicals
Add chemicals such as fluoride
(for dental protection) or lime
(to reduce acidity).
Stor
e
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 sys
tem.
e water treatment process

19
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. e water authority must ensure that
their processes are preventing these levels being exceeded.
Monitoring water for the presence of every species of harmful
microorganisms is not practical or even desirable. is 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. is 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. ese include:
• turbidity (cloudiness) or particle counts
• colour
• pH (how acidic or alkaline the water is)

• disinfectant residuals (a useful indicator of water quality).
e benefit of these indicators is that they can be monitored ‘online’
— that is, as the water is being processed. is 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.
Photo supplied by SA Water Corporation
20
A proactive approach
e current edition of the Australian Drinking Water Guidelines emphasises
the importance of preventive management of drinking water quality. is
approach focuses on identifying and managing risks in a proactive way,
rather than simply reacting when problems arise. e 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. e final stage is to ensure
that existing preventive measures are sufficient to control the hazards and to
improve or replace such measures if necessary.
e current guidelines
include a framework that can be used to apply this risk
management approach to water supply systems of any size. e 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. rough 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.
ere 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. e
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.
21
Small water supplies
Some small communities in Australia use water that is untreated or only
partially treated. e 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. ese 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. ese devices are highly
recommended for anyone using rainwater for drinking.
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.
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).
e process requires relatively little space,
involves no chemical pretreatment, is easily
automated and needs little maintenance. is
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. e
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.
22
Who is responsible for safe

drinking water?
e 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. e 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). ey combine the results of local and
international research with appropriate information from other sources,
such as the World Health Organization. e 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.
e 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 do 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. is 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.
e 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.
e 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.
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 5 mg/L.
erefore, with the exception of microbial
contaminants, occasional results in excess of
the health guideline value generally do 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 2 mg/L and an aesthetic-related value of
not more than 1 mg/L. e 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.
23
Keeping the guidelines up to date
e 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.
e 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. e guidelines also tend to become more stringent as new
research establishes links between contaminants and adverse health effects.
e 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. is
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.
Photo supplied by Ted Gardner, Queensland Department of Natural Resources
National Resource Management Ministerial Council
24
What can I do to help?
Help to keep drinking water safe

ere 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 do 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.
25
Keep your plumbing in good repair
e 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. is 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. e device should be installed by an accredited backflow
prevention plumber. Check with your local authority if you are unsure.
26
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.
e 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. e 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.
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. e
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.
rough 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).
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
* More information on the 5A rating water-efficiency scheme is available at www.wsaa.asn.au