Backflow Prevention

Backflow prevention is the protection of a potable water supply from contamination caused by water flowing in the reverse direction through plumbing. Backflow can occur when pressure changes create back-siphonage or back-pressure, potentially drawing contaminated water into a clean water system.

Common causes of backflow

• Back-siphonage: a drop in supply pressure draws water or contaminants backward through a connected outlet.
• Back-pressure: pressure from another system or source forces water backward into the potable supply.

Backflow prevention devices

Depending on the hazard and plumbing application, protection may include an air gap, vacuum breaker, double-check assembly or reduced-pressure principle assembly. The appropriate device must be selected and installed according to plumbing code and the local authority’s requirements.

Why it matters in foodservice

Commercial kitchens use water connections for dishwashers, hose stations, mop sinks, beverage equipment and other applications. Cross-connections between potable water and potentially contaminated sources must be identified and protected.

Chef’s safety note: Do not remove, bypass or modify a backflow prevention device. Inspection, testing and maintenance must be carried out according to local requirements by qualified personnel.

Key distinction: Backflow is the unwanted reverse flow of water; a backflow prevention device is the plumbing protection installed to reduce that risk.