What causes backflow?
There are two ways in which backflow can occur:

  • Backsiphonage: Backsiphonage can occur when there is a sudden reduction in the water pressure of the distribution system, such as during firefighting or when a water main breaks. At these occurrences, water flow can be reversed. This reversal can create a suction effect and draw potential contaminants into the potable (drinking) water system.
  • Backpressure Backpressure is created when pressure in the customer’s water system exceeds the pressure in the potable (drinking) water system. This can force the potable water to reverse its direction of flow through a cross-connection between the two systems. Potential contaminants can then enter the potable water system.

Show All Answers

1. What is backflow?
2. What is a cross-connection?
3. What causes backflow?
4. How can backflow be prevented?
5. What is a backflow prevention assembly?
6. Who is required to have a backflow prevention assembly?
7. Who can test backflow prevention assemblies?