A device that works to protect potable water from contamination or pollution due to backflow. In layman’s terms, it’s essentially a device that stops water from flowing backward in your pipes. This backflow could introduce contaminated liquids, gases, or suspended solids into your drinking water.
More detailed definition: A mechanical device which prevents backflow. In irrigation, it is used to protect the potable water supply from potentially contaminated irrigation water. There are several types of backflow preventers. The choice of backflow preventer used depends on the degree of hazard and the particular piping arrangement involved. Virtually all regulatory agencies in the United States require backflow prevention devices to protect the domestic water supply from contamination by the backflow of irrigation water. In areas where it is not required, it is highly recommended. Consult local building codes for laws applicable in your area.
EXAMPLE:
Backflow preventer devices are necessary to preserve our society’s drinking and bathing water.
