Cross Connection Practice Exam

What are the two types of backflow?

1. Backpressure and Backsiphonage

2. Pressure and Vacuum

3. Cross-Connection and Isolation

4. Siphon and Gravity

The correct answer is: Backpressure and Backsiphonage

Backflow refers to the unwanted reverse flow of contaminants into a potable water supply. The two primary types of backflow are backpressure and backsiphonage. Backpressure occurs when the pressure in a non-potable system exceeds the pressure in the potable system, causing water to flow backward into the drinking water supply. This situation can happen due to various reasons, such as a pump creating higher pressure in a system or thermal expansion of water in a closed system. Backsiphonage, on the other hand, happens when there is a negative pressure or vacuum in the water supply system, causing water to be drawn back into it from an external source. This situation can occur during events like a sudden drop in water pressure due to a main break or extensive water use in a nearby area. Understanding these two types of backflow is crucial in preventing cross-connections, which can lead to contamination of drinking water systems. Their identification allows for the implementation of appropriate preventive measures, like the installation of backflow prevention devices, to maintain safe and potable water.