Drinking water quality samples

We regularly check the quality of the drinking water we supply to our customer by taking samples, which are tested at a National Association of Testing Authorities (NATA) accredited laboratory. Water quality sampling taps are located in various locations throughout drinking water towns.

Sampling frequencies are in accordance with the Safe Drinking Water Act (2003) and the Safe Drinking Water Regulations (2005). Escherichia Coli, trihalomethanes and turbidity frequencies are specified in Schedule 2 of the Regulations.

The below table shows water quality parameters and their frequency of sampling for which results are available on the website. Additional parameters are tested for at some localities based on risk, with results available on request.

Weekly*

Monthly*

Quarterly*

Annually*

· Escherichia coli

· turbidity

· pH

· free/total chlorine

· plate count 37ºC

· coliforms

· fluoride^

· electrical conductivity

· aluminium (acid soluble)

· trihalomethanes

· lead

· hardness

· alkalinity

*Two samples are taken on each occasion from Ararat, Horsham and Stawell.

^Only for towns with fluoride as treatment (Ararat, Horsham, Natimuk, Ultima)

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Test Description:

Alkalinity is the sum of the carbonate, bicarbonate and hydroxide content in the water. It is a measure of the capacity of the water to neutralize the acids. Alkalinity is an important water quality parameter that can impact coagulation in the treatment of drinking water and corrosion in pipes.

Aluminium may be present in water through natural leaching from soil and rock, or from the use of aluminium salts as coagulants in water treatment. No health-based guideline is set for aluminium but a concentration of below 0.2 mg/L is recommended for aesthetic reasons.

Coliforms are gram-negative nonsporing rod-shaped bacteria, capable of aerobic and facultative anaerobic growth.They are found in large numbers in the faeces of humans and other warm-blooded animals.Coliforms are "indicator" organisms associated with bacteriologically polluted water.

Electrical conductivity of water is directly related to the concentration of dissolved ionized solids in the water. When correlated with laboratory TDS measurements, electrical conductivity provides an approximate value for the Total Dissolved Solids concentration

E. coli is the most common thermotolerant coliform present in faeces and is regarded as the most specific indicator of recent faecal contamination. E. coli, (or thermotolerant coliforms) numbers can be determined using membrane filtration (MF) for concentration of the organisms from water.

Fluoride is added to drinking water for dental health benefit as directed by DHHS. The concentration of Fluoride in drinking water should not exceed 1.5 mg/L. Currently only Ararat, Horsham, Natimuk and Ultima have Fluoride added to the drinking water supply. For more information about water fluoridation, refer to the Department of Health’s website: Water fluoridation in Victoria - health.vic

Chlorine is also classified as a disinfectant, meaning that it is capable of killing bacteria, algae and other organic material instantly.When it is added to the water, it forms free available chlorine.Chlorine is also used to disinfect sewage and waste water, swimming pool water, in-plant supplies, and industrial cooling water. Free chlorine is measured in localities with chlorination systems. Total chlorine is measured in locaties with chloramination systems.

Hardness is caused predominately by calcium and magnesium salts. Hard water can increase the amount of detergent and soap required for cleaining, it can also cause scale build-up in pipes and fittings. To minimise undesirable build?up of scale, hardness in drinking water should not exceed 200 mg CaCO₃/L.

Lead is the most common of the heavy metals. Lead occurs in drinking water via dissolution from natural sources or household plumbing systems containing lead. Based on health considerations, the concentration of lead in drinking water should not exceed 0.01 mg/L.

pH is a measure of the hydrogen ion concentration of water.It is measured on a logarithmic scale from 0 to 14. A pH of 7 is neutral, greater than 7 is alkaline, and less than 7 is acidic.pH of drinking water should be between 6.5 and 8.5.

Plate count is a method for measuring the number of bacteria in a water sample able to grow on a simple organic media at a given temperature and incubation period. These bacteria have no direct relationship to faecal contamination or health risks but are used as a general indicator of the microbiological content of water.

Trihalomethanes are present in drinking water principally as the result of disinfection using chlorination or, to a much lesser extent, chloramination. Chlorine, which produces hypochlorous acid when added to water, can react with naturally occurring organic material, such as humic and fulvic acids, to produce trihalomethanes.

Turbidity is caused by the presence in the water of fine suspended matter such as clay, silt, colloidal particles, plankton and other microscopic organisms.Turbidity is a measurement of the light scattering property of water, and the degree of scattering is dependent on the amount, size and composition of the suspended matter.Higher turbidity levels are often associated with higher levels of disease-causing microorganisms such as viruses, parasites and some bacteria.

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Drinking water quality samples

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