The answer to 'why is my pipe foul smell' is that a foul odor coming from your pipes is often caused by a blockage or buildup in the pipes. This can lead to the accumulation of bacteria, decomposing organic matter, and other unpleasant materials that emit unpleasant odors. Common causes include a clogged drain, a dried-out P-trap, or a sewer line issue.
Some common symptoms of a pipe odor problem include a persistent bad smell, gurgling sounds from the drains, and slow draining sinks or tubs. To address the issue, you can try DIY solutions like using a plunger or drain cleaner, but if the problem persists, it's best to call in a professional plumber to properly diagnose and fix the underlying issue.