What we test for

Health parameters

E. coli

Escherichia coli (E. coli) is a type of bacteria used as an indicator of microbiological water quality. The health guideline value for E. coli is that none should be detected in a minimum 100 mL sample.

What does a sample failure mean?
The presence of E. coli in a sample does not itself indicate that the drinking water is unsafe, but may indicate that the source water or the treatment, transmission, or reticulation components of the SEQ interconnected water suppy network may be compromised.

E. coli are occasionally detected in treatment, transmission or reticulation systems that are operating effectively.

In the absence of the Australian Drinking Water Guidelines 2011 prescribing a long-term performance measure for microbial water quality, for the purposes of the Customer Confidence Report (Bulk Water), 12 monthly microbial performance is benchmarked against the Public Health Regulation 2005 annual value.

The Australian Drinking Water Guidelines acknowledge that it is unrealistic, both from a statistical viewpoint and practically, to expect a water supply system to have zero indicator bacteria at all times. However, all positive results for E. coli are taken seriously and are reported to the Office of the Water Supply Regulator and will be investigated to ensure the system’s integrity.

Copper

Copper is a mineral widely distributed in rocks and soil and is used in domestic plumbing because it is relatively resistant to corrosion.

Copper is present in uncontaminated surface waters at very low concentrations.

Copper has both an aesthetic and a health guideline value. The aesthetic guideline value is 1 mg/L. The health guideline value is 2 mg/L.

What does a sample failure mean?
Aesthetically, copper can cause a metallic taste, blue-green discolouration of the water and staining issues. Concentrations above the aesthetic level may cause blue or green stains on bathroom fixtures.  

Copper is not normally present in the water supplied from a water treatment plant, but may dissolve into the water supply from plumbing and pipes. When a sample exceeds the guideline for copper, this is usually limited to a particular property or small geographical location as it is generally caused by the local plumbing. It is unlikely that a copper exceedence would affect the bulk supply network.  

Fluoride

Low levels of fluoride occur naturally in many water sources. Fluoride is also added to drinking water in many parts of the world, including South East Queensland, to help reduce tooth decay. Not all water sources in South East Queensland are presently fluoridated.

The concentration of fluoride at any given point will vary if a fluoridated source is blended with a non-fluoridated source.

The Water Fluoridation Regulation 2008 sets the prescribed concentration for South East Queensland at 0.8 mg/L. This has been determined as being the level at which the optimum oral health benefit is achieved.

The Public Health Regulation 2005 standard is based on health considerations and states the maximum concentration of fluoride.

The Customer Confidence Report (Bulk Water) only covers compliance with the health standards set in the Australian Drinking Water Guidelines and the Public Health Regulation 2005. The health guideline value for fluoride is 1.5 mg/L.

What does a sample failure mean?
The guideline value is set in order to maximise fluoride's beneficial effects. It is unlikely that a fluoride failure would affect the bulk supply network.

Lead

Lead can be present in drinking water as a result of dissolution from natural sources or from household plumbing systems containing lead.

Lead is not normally present in the water supplied from a water treatment plant, but may dissolve into the water supply if lead piping or joins are present in plumbing.

The health guideline value for lead is 0.01 mg/L.

What does a sample failure mean?
When a sample shows lead present above the guideline value, this is usually limited to a particular property or small geographical location as it is caused by the local plumbing. It is unlikely that a lead exceedence would affect the bulk supply network.

Manganese

Manganese is a mineral present in the environment which can enter the water supply in its soluble form.

Manganese has both an aesthetic and a health guideline value. The aesthetic guideline value is 0.1 mg/L. The health guideline value is 0.5 mg/L.

What does a sample failure mean?
At concentrations exceeding the aesthetic guideline value of 0.1 mg/L, manganese imparts an undesirable taste to water and stains plumbing fixtures and laundry.

Health implications for manganese are unlikely because water will become unacceptable to consumers long before the concentration reaches the health guideline value.

Total trihalomethanes

Trihalomethanes are a by-product of the chlorination and chloramination disinfection processes. Disinfection is essential to destroy microorganisms that could otherwise be harmful.

The health guide value for total trihalomethanes is 0.25 mg/L.

What does a sample failure mean?
The health guideline value for total trihalomethanes is set with a wide safety margin and is based on long-term exposure; individual failures of the guidelines are very unlikely to represent a significant health risk.

The Australian Drinking Water Guidelines encourage action to reduce total trihalomethanes, but not at the expense of compromising disinfection. Non-disinfected water poses significantly greater risk to health than total trihalomethanes.

Aesthetic parameters

Alkalinity

Alkalinity is a total measure of the parameters (carbonate, bicarbonate and hydroxide content) in water that have acid-neutralising ability.

Alkalinity is different to pH, which measures the strength of an acid or base. Alkalinity indicates a solution’s power to react with acid and ‘buffer’ its pH — that is, the ability to keep its pH from changing.

Alkalinity can be naturally occurring, or altered due to water treatment chemicals. There is no guideline value set for alkalinity.

What does a sample failure mean?
There is no guideline value for alkalinity so there will be no failure of this sample result. However, some industries have to alter processes or machinery settings based on the alkalinity of the water.

Aluminium

Aluminium may be naturally present in water or from the water treatment process.

Aluminium sulphate is also used extensively as a coagulant in order to treat water. The aesthetic guideline value for aluminium is 0.2 mg/L.

What does a sample failure mean?
High aluminium may result in ‘milky’ coloured water, though the occurrence of this also depends on factors such as pH and the water treatment chemicals used.

Aluminium can be present in silt, which can accumulate as sediment in the distribution pipes. High aluminium may be caused by the re-suspension of these materials. There is no health affect.

Hardness

‘Hard’ water is caused by dissolved calcium and magnesium salts, particularly carbonates and bicarbonates.

The aesthetic guideline value for total hardness, reported as calcium carbonate, is 200 mg/L.

What does a sample failure mean?
There is no health risk with hard water, however, it can be difficult to lather and can cause scaling problems in hot water systems.

Iron

Iron can occur naturally in water sources and may also enter the water supply from the corrosion of iron water pipes. The aesthetic guideline value for iron is 0.3 mg/L.  

What does a sample failure mean?
High iron concentrations may affect the taste of water or give water an undesirable rust-brown appearance.  It can cause staining of laundry and plumbing fittings and blockages in irrigation systems.  There is no health affect.

pH

pH is a measure of how acidic or alkaline the water is in the system. pH is affected by the source water and also the water treatment process. The aesthetic guideline value for drinking water is between pH 6.5 to pH 8.5.

Water that is naturally pH low may need to be conditioned in order to ensure it complies with the guidelines. This is most commonly achieved by adding lime or passing the water through a bed of limestone chippings.

What does a sample failure mean?
Water with low pH may be corrosive to pipe work and household fittings.  Water with a high pH can cause scaling issues and affect the taste of water. There is no health affect.

Total dissolved solids

Total dissolved solids are inorganic salts and small amounts of organic matter that are dissolved in water. The aesthetic guideline value for total dissolved solids in drinking water is 600 mg/L.

What does a sample failure mean?
A high level of total dissolved solids can affect the taste of drinking water. Extremely high levels can cause scaling in pipes and fittings. There is no health affect.

Editions of the Customer Confidence Report (Bulk Water) published prior to the effective date of the Australian Drinking Water Guidelines 2011 had assessed results for total dissolved solids against a now usperseded guideline value. The method to assess results published after this effective date has since been amended to reflect the in-effect 2011 guideline value.

True colour

‘True colour’ is the colour of the water after particles have been removed by filtration. It is a measure of whether the water appears coloured or tinted due to parameters dissolved in the water.

The aesthetic guideline value for colour is 15 Hazen Units (HU).

What does a sample failure mean?
Colour is an aesthetic parameter and of no health significance, although highly coloured water will be unacceptable to consumers.

The guideline value is based on the colour that is just noticeable in a glass of water.

Turbidity

Turbidity is caused by the presence of fine suspended matter such as silt, clay, plankton, and other organisms in the water. It is a measure of the extent to which water appears cloudy or hazy.

The aesthetic guideline value for turbidity is 5 Nephelometric Turbidity Units (NTU). At this level turbidity is just noticeable to the average person.

What does a sample failure mean?
High turbidity can give water a cloudy or muddy appearance making it unacceptable to consumers; however, there is no health affect.

Limits of detection and reporting

Water samples sometimes contain concentrations of chemicals below the limit at which a laboratory can adequately detect. The limit of detection is the lowest quantity of a substance that can be identified before it cannot be found. Limits of detection vary between different laboratories due to differing test methods, and also change over time as the methods improve. Sometimes this is referred to as the limit of reporting.

In the reporting a result that is less than the limit of detection may be reported as "<" (less than).

There are also instances where laboratories provide results for test samples that are at a number of significant figures that do not reflect the limit of detection or the number of decimal places reported upon. Within the Customer Confidence Report (Bulk Water) where this occurs a trailing zero may be added to the result for standardisation of reporting.  

An example of this is as follows:

'A sample result for Aluminium at Capalaba Water Treatment Plant with a limit of detection of 0.005mg/L may receive a sample result of 0.11 mg/L,  where the laboratory has not provided the sample value to three decimal places. In this instance in the reporting tool will update the 0.11 mg/L value to three decimal places attaching a trailing zero and will now be presented as 0.110 mg/L.

What we test for