Page content: 7.1 Control measures | 7.2 Prevention

Water contaminated with animal or human sewage or pasture runoff can contain harmful micro-organisms such as Cryptosporidium, Giardia, E. Coli, Campylobacter, Salmonella, and enteric viruses. Consuming water containing these micro-organisms, either from rivers, channels, pools, spas, drinking water supplies, private water tanks or flood water, may cause severe gastro-intestinal disease. Many small and remote communities around Victoria, including camping grounds and rural accommodation sites, obtain water from private supplies which may be unregulated in terms of the quality of drinking water.

Establishing a causative link between an outbreak of disease and particular water sources is often very difficult, particularly in the early stages of an investigation.

If a gastrointestinal illness outbreak is suspected to be water-borne, the EHO should discuss the situation with the REHO who will liaise with Disease Control Victoria and the Environmental Health Unit. The situation will be assessed to determine the most appropriate course of action. This normally includes initiating an appropriate investigation and establishing clear lines of accountability and communication.

The Health (Quality of Drinking Water) Regulations 1991 (made under the Health Act 1958) apply to "systems supplying water intended for human consumption" (Regulation 4). The objective, stated in Regulation 2, is to:

" ...protect the public health by minimising the risk of contracting illness and disease from water supply systems controlled by water authorities."

The Regulations require all water supply authorities to:

• Take reasonable precautions to ensure that their water supply systems and catchments are protected from contamination
  
• Report within 24 hours if the drinking water supply is believed to be associated with a water-borne illness or risk to public health
  
• Inspect and report on their water supply catchments, at least every three years, to DHS
  
• Routinely monitor and report on microbiological quality, in a prescribed manner, to DHS

The Regulations also enable the Chief General Manager of DHS to:

• Require sampling of water supplies for any substance and to specify the number, frequency or location of samples
  
• Require water authorities to inspect their catchments more frequently than prescribed
  
• Approve laboratories for analysis of samples from drinking water supplies
  
• Direct the purification of water supplies where public health is at risk
  
• Direct the boiling of water supplies where public health is at risk

The Regulations also include a schedule setting out monitoring frequency and a maximum interval between samples.

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7.1 Control measures

If a water source is suspected to be contaminated or a cause of disease, the Environmental Health Unit will usually:

• Contact the manager or operator of the water system (such as a water authority, or pool or camp manager) to determine their immediate response to the incident
  
• Obtain, where possible, data on water quality and duration of incident, including monitoring results for a range of pathogens and indicator organisms
  
• Evaluate the impact of options such as pool or water supply closure, or the provision of alternative supplies
  
• Participate in epidemiological investigations, including the collection of water, ice or other environmental samples.

In the event of a water-borne outbreak, the responsible body (eg the water authority) is advised to take voluntarily actions to halt further illness, after consultation with DHS. However, DHS may direct them to undertake specific actions if necessary. Actions may involve issuing boil water notices, closing a pool or spa, or using an alternative supply, depending on the individual circumstances.

In the case of drinking water supplies, the water authority would normally publicly notify consumers. However, DHS would also usually issue a general media release about the incident and precautions that the public can take to minimise health risks. DHS retains a general enforcement and prosecution power that can be used as a "last resort" in certain circumstances.

7.2 Prevention

Local government has general public health responsibilities to ensure that private water supplies in their area do not pose a risk to public health.

Prevention strategies for businesses using private water supplies for commercial purposes (eg school camps) include:

• Ensuring that surface run off and leakage from sewer pipes or sullage drainage cannot contaminate water storage or reticulation
  
• Sealing water storage tanks to prevent the entry of animals and birds
  
• Monitoring water quality for organisms which indicate contamination
  
• Operating suitable treatment facilities
  

Prevention strategies for swimming pools and spas include:

• Ensuring that pools and spas are cleaned and treated regularly in accordance with the requirements of the Health (Infectious Diseases) Regulations 1990 "Water Purification Standards for Public Swimming Pools and Spa Pools"
  
• Having a written policy for faecal accidents
  
• Having signage advising patrons not to swim if they have had gastroenteritis in the previous week
  
• Having signage advising patrons to shower prior to entering the pool or spa

Enteric (gastro)

Gastroenteritis

Gastroenteritis - viral

Guidelines for the Investigation of Gastrointestinal Illness - Introduction

Zoonoses (by animals)

Reducing the risk of gastroenteritis at open farms, petting zoos & animal exhibits