A mechanical device that prevents the return flow of water and any dissolved chemicals back into the water supply.
A backflow preventer that is not testable, and specific installation requirements in order to operate properly. Category: Public Works
A backflow prevention device is used to protect water supplies from contamination. Many types of backflow devices also have ports so that they can be tested or examined to ensure that they are functioning properly. A check valve is a common form of backflow preventer.