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Water contaminants and public health risks

Queensland Health is often involved in investigating water contamination events to determine the presence and extent of public health risk associated with the contamination as well as providing direction or guidance in the management of these risks.

Resources and more information about some ‘common’ water quality related health risks are outlined below.

If you suspect water contamination:

  • Contact your drinking water supplier if it relates to the safety of your drinking water.
  • Call 13 HEALTH (13 43 25 84) or visit your GP for specific health related enquiries.

E. coli in drinking water

E. coli are bacteria that are used to monitor faecal contamination in the water. Water is tested to determine the level of E.coli which in turn indicates the presence of other disease-causing organisms.

Read more about E.coli

Harmful algae blooms

Water contaminated by blue-green algae (i.e. harmful algae blooms) can constitute a health risk to humans. Of particular public health concern is the production of toxins by the blue-green algae.

Read more about blue green algae, health risks for humans and algal blooms and toxins water testing available.


Legionnaires’ disease is a type of pneumonia caused by the Legionella bacteria. Humans might contract this disease by inhaling microscopic/invisible droplets (aerosols) of contaminated water from man-made systems such as hot or warm water systems, showerheads, spa baths and fountains.

Read more about Legionella and Legionnaires disease:


Most Salmonella infections occur after eating contaminated food but can also be occur via consumption of contaminated drinking water. Salmonella bacteria are found in humans and in wild, farm and pet animals, and birds. An infected animal’s faeces can contaminate water supplies, and water tanks, or be prevalent in water sources following a flood.

Read more about salmonella


Cryptosporidium is a microorganism that lives in the bowel and is found in the faeces of infected humans and domesticated animals (particularly cows and sheep). It is normally spread through poor hygiene, usually by ingesting contaminated food or water. Illness can occur from ingestion of water during swimming or immersion in contaminated water

Read more about Cryptosporidiosis

Primary amoebic meningoencephalitis (PAM)

Primary amoebic meningoencephalitis (PAM) is a rare but severe illness caused by the Naegleria fowleri amoeba.

Naegleria fowleri is a single-celled amoeba that occurs naturally in untreated warm (25°C to 40°C) water. It can grow in warm stagnant water bodies such as dams, poorly managed swimming pools and in untreated water lying in long distance, above ground pipelines and hoses.

Water drawn from deep artesian bores and cooled in above ground uncovered dams on rural Queensland properties is particularly at risk from Naegleria fowleri.

Read more about safe water on rural properties (PDF 184KB)
This latest version contains an update of the quantities of chlorine added to water storage tanks (Table 1)Read more about Primary amoebic meningoencephalitis (PAM)

Last updated: 7 November 2018