I went to my basement and I discovered a rotten egg smell in the area near my sump pump. The sump only takes away ground water and is not part of a septic system. At first I thought it was a gas leak, however the gas company came out and could not find a leak. Is it possible that the sump is causing the smell. I have smelled what a dead rodent smelled like and it was significantly worse and substantially different (this may be wishful thinking on my part) thanks for any help.