What is the maximum length of a residential 2" trap arm with a 2" trap to the vent?

Explanation:

The maximum length of a residential 2" trap arm with a 2" trap to the vent depends on the building codes applicable in the area where the construction or remodeling is taking place. Generally, the Uniform Plumbing Code (UPC) and the International Residential Code (IRC) provide guidelines for these measurements.

For instance, under the UPC, a 2" trap arm should not exceed a length of eight feet from the trap weir to the vent without additional vents, turns, or cleanouts. However, these codes can vary by location, and it's important to consult local building codes or a professional plumber for the most accurate information.