What are the health risks to swimmers?

Learn what pathogens might be found at a polluted swimming site and what illnesses they can cause.

Our water quality monitoring shows that water quality is safe for swimming at most of NSW’s ocean beaches almost all of the time. However, after heavy rain, pollution from stormwater and sewage overflows can make water quality unsuitable. As a general precaution, we always advise that you avoid swimming during and at least one day after heavy rain at ocean beaches, and for up to three days at harbour or estuarine swimming areas to allow the pollution to dissipate. 

If you feel unwell please seek medical advice from a doctor or hospital.

Call Triple Zero (000) in an emergency.

For information on infectious diseases and outbreaks in NSW, please see the NSW Health website.

Pathogens are organisms that can cause disease in humans. The most common types of waterborne pathogens are:

  • enteric bacteria: which are single-celled organisms that live in the intestinal tracts of all warm blooded animals. Several groups of these bacteria are pathogenic, including Campylobacter, Salmonella, Pseudomonas and Shigell, and are responsible for causing gastroenteritis, skin and ear infections and bacillary dysentery.
  • viruses: which are genetic material surrounded by a protein shell including Rotaviruses, Adenoviruses,Noroviruses and Hepatitis. They are known to cause diarrhoea, vomiting, hepatitis A and E and respiratory disease.
  • protozoa: which live in water as hardy dormant cysts and once ingested, can live as parasites in humans and animals. Examples are Giardia and Cryptosporidium which are known to cause diarrhoea.
  • worms which can cause vomiting, coughing, chest pain, fever and gastroenteritis.