What device is used to prevent backflow in plumbing systems?

A backflow preventer is a crucial device in plumbing systems designed to protect potable water supplies from contamination caused by backflow. Backflow occurs when water flows in the reverse direction due to pressure changes in the plumbing system, which can happen through back siphonage or back pressure.

The backflow preventer typically consists of one or more check valves that allow water to flow in only one direction. Its primary function is to ensure that, in the event of a negative pressure or any condition that could cause reverse flow, contaminated water from irrigation systems, industrial processes, or other non-potable sources does not enter the clean water supply.

While a check valve is used in many applications to allow flow in one direction, the backflow preventer is specifically designed and tested for backflow prevention, making it a more comprehensive solution for ensuring the safety and integrity of drinking water systems. This makes the backflow preventer the appropriate choice for this particular function in plumbing systems.