Floor drains shall have traps that are designed to hold water or other compatible liquids in them.

• A. True
• B. False
• C. Only if vented
• D. Not required

Answer: (A)

The main idea is that a floor drain must have a trap that creates and maintains a liquid seal to block sewer gases from entering the space. That seal is what prevents odors and gases; it is maintained by water or another compatible liquid staying in the trap. Venting can help prevent siphonage, but it doesn’t remove the need for the trap to hold liquid. If the trap dries out, the seal is broken and gases can pass. So the statement is true because floor drains are designed to maintain a liquid-filled trap to protect occupants from sewer gases.