Private water supply testing

If you are providing or using drinking water not sourced from a reticulated licensed water supply, you should get your water tested regularly.

This applies if the water comes from a bore, rainwater tank or surface water source.

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Drinking water should be regularly tested to make sure it is free of harmful bacteria or chemicals and safe for drinking.

The Australian Drinking Water Guidelines 2011, updated in 2018 state the greatest health risk from drinking water is pathogenic microorganisms such as bacteria.

Other sources of contamination can come from:

  • viruses
  • protozoa and mycobacteria
  • toxins produced by bacteria and algae.

Drinking water samples are tested for an indicator bacteria called E. coli.

Bacteria may be in the water as a result of human or animal faecal contamination.

E. coli is found in very high numbers in the intestines of animals and humans. This is why it is a good indicator of recent faecal contamination in drinking water.

Not all E. coli is pathogenic. The results of testing will give an indicator of the condition of the water source. Read below for more information.

Water can be tested for contamination by any NATA-accredited laboratory.

These labs can provide:

  • sterile prepared sample bottles
  • advise on how to collect a water sample
  • information on the best delivery method and time.

You will need to pay for water sample testing.

To find out more about testing laboratories, read about bore water testing.

Common bacteriological analysis will provide the numbers of viable bacteria, total coliforms and E. coli present in the water sample.

The analysing lab will normally report if a test is a pass or fail based on the presence of these indicator organisms.

You can contact the testing lab or Environmental Health for further assistance with understanding your water results.

Bacteria

All water has some form of bacteria in it.

The presence of bacteria does not mean the water is unsafe to drink.

Only disease-causing bacteria known as pathogens lead to disease.

Coliforms

Total coliforms may not present a direct health risk, but can provide information on the efficiency of drinking water disinfection.

Therefore increased concentrations of coliforms should be investigated.

E. coli

E. coli present in drinking water means that human or animal faeces have contaminated the water.

Faeces can harbour a number of pathogenic or disease causing organisms.

To make sure water is safe for drinking, no E. coli should be detected in any 100 millilitre (ml) water sample.

There are a number of treatment processes that remove E. coli and other pathogenic microorganisms from a drinking water supply.

These include filtration, UV and chlorine disinfection.

If your drinking water sample is positive for E. coli you should do either of the following until repeat sampling shows it is E. coli free:

  • boil and cool water before using it for drinking and brushing your teeth
  • use bottled water.

Last updated: 14 February 2020

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