The answer to 'why is my drain trap' is that the drain trap may be clogged, dried out, or damaged. The drain trap is the curved section of pipe under your sink or bathtub that holds a small amount of water to prevent sewer gases from entering your home. If the trap is not functioning properly, it can lead to unpleasant odors, slow drainage, or even flooding.
Common causes of drain trap issues include debris buildup, a dried-out trap, or a cracked/broken trap. Symptoms can include foul smells, slow draining water, or water backing up. Solutions may involve cleaning out the trap, refilling a dried-out trap, or replacing a damaged trap.