What is the purpose of a hose bib with an anti-siphon mechanism, and where should it be installed?

• A. To prevent backflow from a garden hose into the cold water supply; installed on external outlets with anti-siphon devices
• B. To reduce water usage
• C. To heat garden water
• D. To route water to indoor fixtures

Answer: (A)

Backflow prevention is the idea behind a hose bib with an anti-siphon mechanism. When a hose is attached to an outdoor faucet, water can be drawn back into the home’s cold-water system if the hose end is submerged in a pool, bucket, or chemical container or if pressure conditions change. The anti-siphon device, often a vacuum breaker, allows air to enter the line when suction would occur, breaking the siphon and stopping any contaminated water from flowing back into the potable supply. This protection is provided by installing the outlet on exterior fixtures that supply potable water, with the anti-siphon mechanism either built into the hose bib or added as a separate vacuum breaker at the outdoor outlet.