What is the minimum trap size for a shower?

What is the minimum trap size for a shower?

• A. 1 1/2" Minimum Trap Size
• B. 3" Minimum Trap Size
• C. 2" Minimum Trap Size
• D. 4" Minimum Trap Size

Answer: (C)

The main idea is that a trap must be large enough to handle the shower’s flow and maintain the water seal that blocks sewer gases. Showers discharge a relatively high volume, and if the trap is too small, rapid discharge can siphon the trap and compromise the seal. Codes require a minimum of 2 inches for a shower trap to prevent this and to match the typical 2-inch waste pipe used for a shower. A smaller trap, like 1 1/2 inches, would be undersized for the shower’s flow, while a much larger trap isn’t necessary for a standard residential setup. So, the minimum trap size for a shower is 2 inches.

The main idea is that a trap must be large enough to handle the shower’s flow and maintain the water seal that blocks sewer gases. Showers discharge a relatively high volume, and if the trap is too small, rapid discharge can siphon the trap and compromise the seal. Codes require a minimum of 2 inches for a shower trap to prevent this and to match the typical 2-inch waste pipe used for a shower. A smaller trap, like 1 1/2 inches, would be undersized for the shower’s flow, while a much larger trap isn’t necessary for a standard residential setup. So, the minimum trap size for a shower is 2 inches.