What is the required water seal depth for traps?

The required water seal depth for traps is typically set at 2 inches. This measurement is important because the water seal acts as a barrier to prevent sewer gases from entering a building through the plumbing system. A 2-inch water seal is sufficient to provide a reliable barrier while also ensuring that the trap maintains a good balance between preventing drain clogs and allowing for the drainage of wastewater.

In practice, if the water seal were less than 2 inches, it might not effectively prevent the escape of harmful gases, while if it were significantly deeper, it could complicate drainage and lead to other plumbing issues. Therefore, the 2-inch standard is widely accepted in residential and commercial plumbing systems, aligning with codes and regulations to ensure safety and functionality.