What are the two primary types of backflow?

The two primary types of backflow are backpressure and back-siphonage. Backpressure occurs when the pressure from the downstream system rises above the pressure of the supply system, resulting in water flowing backward into the supply line. This can happen in situations where there’s an increase in temperature, pressure, or any condition that leads to an increase in downstream pressure, often seen in industrial processes.

On the other hand, back-siphonage happens when there is a negative pressure in the distribution system, creating a vacuum that pulls water or contaminants from the downstream source back into the potable water supply. This is commonly caused by sudden drops in system pressure, such as when a fire hydrant is opened quickly or a water main breaks, leading to a situation where contaminants can be drawn into the drinking water supply.

These definitions highlight the critical importance of understanding backflow types in the context of public health and safety, as both types can lead to the contamination of drinking water if proper backflow prevention measures are not in place.