The answer to 'sump pump foul smell' is that a foul odor coming from a sump pump is often caused by a buildup of organic matter, bacteria, or mold growth in the sump pit or pump. This can happen when the sump pump is not maintained properly or if the pit is not cleaned regularly.
Some common symptoms of a smelly sump pump include a rotten egg or sewage-like odor, slime or sludge buildup in the pit, and potentially even visible mold growth. To address this issue, you'll want to clean out the sump pit, disinfect it, and ensure the pump is functioning properly. If the odor persists, it may be necessary to replace the pump or have a plumber inspect the system.