What is the cross-connection risk associated with a garden hose connected to a hose bib, and how can it be mitigated?

• A. There is no risk; hoses are safe.
• B. Backflow contamination risk into potable supply; mitigate with anti-siphon hose bib or an approved backflow preventer.
• C. Risk only if the hose is metal.
• D. Use of a backflow preventer is optional and only recommended in farms.

Answer: (B)

Backflow risk from a garden hose connected to a hose bib arises because the hose can create a path for contaminated water to be drawn back into the potable supply when pressure changes or when the hose end is placed in or near contaminated water. This cross-connection can allow unwanted substances—fertilizers, pesticides, soil, or microorganisms—to siphon into drinking water. The way to prevent this is to install an anti-siphon hose bib or an approved backflow preventer, which stop reverse flow by adding an air gap or by using check valves that block backflow. The risk exists regardless of hose material, and in many situations backflow protection is required by code, so treating it as optional isn’t appropriate.