The answer to 'why is my shower foul smell' is that a foul odor in the shower is often caused by a buildup of mold, mildew, or bacteria in the drain or shower walls. This can happen due to poor drainage, lack of ventilation, or not cleaning the shower regularly.
Some common symptoms include a persistent musty or sewage-like smell, visible mold growth, and slow draining water. To fix the issue, you'll need to clean the shower thoroughly, address any drainage problems, and improve ventilation in the bathroom.