What is Backflow?

What is backflow prevention?
Backflow prevention is the term used to refer to the prevention of an unwanted, reverse flow of water from a potentially polluted source back into the drinking water supply.

When does backflow occur?
Backflow occurs because a condition exists in a water supply system that will cause back-siphonage or back-pressure. Back-siphonage can occur on a property through a vacuum created in the water supply system.

An example of back-siphonage would be a pipeline breakage, can occur within properties when high pressure is generated downstream by pumps, thermal expansion or elevation.
Backflow prevention starts within a property boundary by isolating a possible contamination source from the town mains or storage tanks (rainwater tanks) from the tap or appliance.

What is the safeguard to prevent a backflow occurrence?
A correctly selected backflow prevention device (one way valve) will eliminate any risk of contamination of the drinking water supply. Backflow devices are either testable or non-testable types with the selection dependent on the risk associated with the possible contamination.

Example of potential source of contamination:

• Fire Hose Reels (FHR)
• Irrigation
• Swimming pools
• Vehicle maintenance pits
• Ornamental ponds
• Air Conditioning Towers
• Vehicle/bin washing bays
• Chemical injection areas

Examples of properties requiring backflow prevention:

• Motels
• Hotels
• Vehicle repair workshops
• Shops
• Restaurants
• RV Parks
• Medical and dental surgeries
• Car and plant washing facilities
• Dry cleaners and laundries
• Hospitals and funeral homes
• Club houses for sports
• Schools
• Day care center and kindergartens
• Botanic gardens