A 3 inch p-trap shall have a maximum depth of ____________ inches for the trap seal.

A 3-inch p-trap is designed to maintain a certain amount of water in its seal to prevent sewer gases from entering the building. The depth of the trap seal is critical to ensure that it remains effective; if the seal depth is too shallow, it may allow gases to escape.

The maximum depth for the trap seal of a 3-inch p-trap being 4 inches aligns with plumbing standards that require a balance between having enough water in the trap and preventing excessive depth that could lead to potential drainage issues. A depth of 4 inches provides an adequate barrier against gases while still allowing for the necessary waste flow without risk of blocking.

Depths beyond this, such as 6 inches or 2 inches, would either exceed dimensions recommended for effective drainage or provide insufficient seal. Therefore, the 4-inch seal depth maximizes function and safety, adhering to construction and plumbing codes ensuring efficient waste management.