What is the main purpose of a vacuum breaker in a plumbing system?

The primary function of a vacuum breaker in a plumbing system is to prevent backflow. It is specifically designed to protect the potable water supply from contamination due to backflow conditions. When there is a sudden drop in pressure in the system, a vacuum can form, which might allow contaminated water to flow back into the clean water supply. The vacuum breaker prevents this by allowing air to enter the system, thereby breaking the vacuum and stopping any reverse flow.

While vacuum breakers do address issues related to pressure and vacuum conditions, their main role is focused on ensuring the integrity of the water supply by preventing backflow, which is crucial for maintaining public health standards. Without this mechanism, there would be a significant risk of contamination, especially in systems that are connected to non-potable sources.