Your Business
Backflow Prevention

Cross connection explained

Cross connections are actual or potential physical connections of potable and non-potable water. There is a risk to public health if there is a cross connection between a water supply and a contaminated source. 

The most common situation involving cross connection is with unmetered fire services and internal plumbing of water tanks. Some examples of where potential cross connections are likely to occur are:

  • Market gardens
  • Dairy farms
  • Commercial kitchens, clubs, hotels
  • Dental surgeries
  • Funeral parlours, mortuaries
  • Hospitals, nursing homes
  • Industrial Premises eg chemical plants
  • Dry cleaners
  • Laboratories
  • Mechanical workshops

Cross Connection Control and Backflow Prevention Devices

Both backflow and cross connections can cause health issues for water supply customers. The principal objective of Backflow Prevention is to protect the quality of water supplies by reducing the risk of contamination. Depending on the business activity occurring on the premises, there are different backflow prevention devices designed to minimise the risk of any potential contamination. Under AS/NZS 3500.1 the three hazard ratings are as follows:

  • High Hazard – any condition, device or practice in which connection with the water supply system has the potential to cause death
  • Medium Hazard – any condition, device or practice in which connection with the water supply could endanger health
  • Low Hazard – any condition, device or practice in which connection with the water supply system could constitute a nuisance but not endanger health or cause injury

New Developments require a Backflow Survey and this is provided by a plumber or hydraulic consultant who assess a property for any backflow requirements, usually as a part of a Development Application.
 
Surveys can be submitted in the form of a signed letter or statement which includes the following information:

  • Hydraulic consultant or plumber’s name, address and qualifications (eg license no)
  • Address of property being surveyed
  • Hazard rating of property
  • Type and location of proposed device/s