Water Quality

  • Water Quality

    • How is the water quality protected?

      Answer

      We apply a multiple barrier approach to protecting water quality, where water is:

      • protected within the catchment
      • treated using coagulation and filtration to remove impurities
      • disinfected to protect against microbiological contaminants
      • transported and stored within a closed, well maintained distribution system
      • routinely sampled & analysed for compliance

      Learn more about our multiple barrier approach.

    • What impurities may be present in untreated drinking water?

      Answer

      The following table shows the problems with using untreated drinking water, as specific impurities, or components, have different effects on the composition of the water:

      • Clays and silts - ‘cloudy’ unaesthetic water effect and particles can shield micro-organisms from disinfection.
      • Natural organic matter  - may create taste and odour problems
      • Iron - may create taste, odour and aesthetic problems
      • Manganese - may create taste, odour and aesthetic problems
      • High or Low pH - can cause problems with corrosion, taste and odour problems and ineffective disinfection
      • Micro-organisms - removal of pathogenic micro-organisms is necessary to prevent water-borne illness.

    • What is drinking water hardness?

      Answer

      Hardness refers to the amount of calcium and magnesium salts in water and is the characteristic that affects lathering of soap and scaling of hot water pipes, fittings and heaters. Learn more about drinking water hardness.

    • What level of chlorine is in drinking water supplied by Hunter Water?

      Answer

      The concentration of chlorine in drinking water supplied by us ranges from 0 to about 1.5 mg/L. This is within the recommendations of the National Health and Medical Research Council (NHMRC) Australian Drinking Water Guidelines. Based on health considerations, the guideline for chlorine is that the chlorine residual should be less than 5 mg/L.
      Learn more about chlorination of drinking water supplies.

    • What level of fluoride is in drinking water supplied by Hunter Water?

      Answer

      The typical concentration of fluoride in drinking water supplied by us is one milligram per litre. This is within the recommendations of the National Health and medical Research Council (NHMRC) Australian Drinking Water Guidelines. The dosing range used by us is specified in regulations produced by NSW Department of Health.
      Learn more about fluoridation of drinking water supplies.

    • Why add chlorine to drinking water?

      Answer

      Water is disinfected before it enters the system to ensure that any disease-causing bacteria, viruses, and parasites are destroyed.

      Chlorine is used because it is a very effective disinfectant, and a residual concentration can be maintained to guard against biological contamination in the water distribution system.

      Learn more about chlorination of drinking water supplies.

    • Why add fluoride to drinking water?

      Answer

      Fluoride in water helps prevent tooth decay. It is particularly effective in protecting children’s teeth while they are forming and helps reduce dental decay in adult teeth.
      Learn more about fluoridation of drinking water supplies.

    • Why can’t untreated drinking water be supplied?

      Answer

      The following table shows the problems with using untreated drinking water, as specific impurities, or components, have different effects on the composition of the water:

      • Clays and silts - ‘cloudy’ unaesthetic water effect and particles can shield micro-organisms from disinfection.
      • Natural organic matter  - may create taste and odour problems
      • Iron - may create taste, odour and aesthetic problems
      • Manganese - may create taste, odour and aesthetic problems
      • High or Low pH - can cause problems with corrosion, taste and odour problems and ineffective disinfection
      • Micro-organisms - removal of pathogenic micro-organisms is necessary to prevent water-borne illness.

    • Why use alum to treat drinking water?

      Answer

      Alum is used at our water treatment plants to remove impurities from drinking water.  The use of alum as a coagulant together with filtration is standard practice in conventional treatment processes around the world. The level of aluminium in our drinking water is usually less after treatment than the natural level in the untreated (raw) water. Learn more about alum in drinking water.

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