I have a pit in my garage that is about 8-10 feet down 12" around tube. There was a sump pump in the pit when we bought the house. When it rained hard we would get a great amount of water in the basement. One day I noticed a metal cover in the garage, so I took it off and there was a broken down pump in this pit. When I pulled the pump out I noticed it was covered with sulfur like mud. I went to the local hardware store and bought a new one and installed it. Everything was working fine, for about a year then one day I heard the pump running and it would not shut off. I pulled the pump back out of the pit and noticed that the sulfur ate throw the housing of the pump. I think the reason that the pit is there, is because there are 2 drain pipes 4" that run into this pit then the water is pumped out by the sump pump. The problem is that the pump that is in the pit is a float type and the base is setting in that sulfur just getting destroyed.