A sump pump pit usually smells bad because water has been sitting in it long enough to grow bacteria, or because debris and organic material have collected at the bottom. In some cases, a dry pit or a drain connection lets sewer gas into the basement.
Standing Water
During dry spells, the pit may hold a small amount of water that the pump does not remove because the float never rises high enough. That still water can grow bacteria and give off a sour or rotten smell. The smell may get stronger in warm weather or after the basement has been closed up for a while.
Debris in the Pit
Leaves, soil, insects, and even small animals can end up in a sump pit. As this material breaks down, it causes odors. Sediment and silt also build up over time and can trap smells.
Sewer Gas
A sump pit is meant for groundwater, not sewage. But some basements have floor drains or laundry lines that connect near the pit. If a drain trap dries out or a line is connected the wrong way, sewer gas can reach the area. A strong rotten egg smell that does not go away may point to this kind of problem.
Reducing the Odor
- Keep a tight-fitting lid on the pit
- Have the pit cleaned of debris and silt
- Make sure nearby floor drain traps stay filled with water
- Test the pump so it runs and moves water out
Keep your hands out of the pit, since the pump and float are connected to electricity. Cleaning the pit is best done with the pump unplugged by someone trained to do it safely.
If the smell comes with a pump that runs oddly or not at all, getting the pump checked and the pit cleaned can fix both problems. If you suspect sewer gas, you can ask our plumbers to trace the odor by calling (833) 603-1840.