How can the strength of a trap seal be increased without violating plumbing codes?

Increasing the strength of a trap seal involves enhancing the depth of water that remains in the trap to create a more effective barrier against sewer gases without violating plumbing codes. Installing an extra deep trap accomplishes this by providing additional water depth, which increases the water column and helps maintain a seal that prevents gas from escaping.

This method is compliant with plumbing codes, which typically outline specific measurements and requirements for trap installations. A deeper trap can more effectively hold the water seal necessary to provide proper drainage without compromising safety or performance.

The other choices might not effectively achieve the desired increase in trap seal strength while also ensuring compliance with regulations. Installing a larger trap may not guarantee a deeper seal, as it could change the trap's capacity for maintaining an adequate water level. Similarly, using different pipe materials does not directly impact the depth of the water in the trap. Adding more water, while it might seem beneficial at first, is not a feasible or code-compliant solution as it could lead to overflows or drainage issues.