My house is a amall ranch with a full basement built around 1950. I have a small plug in the floor. I can't figure out what it is. I was thinking perhaps at one point it was a sump pit that was sealed over. The cement has obviously been patched around the pipe about the diameter of a sump pit. Perhaps the basement was always dry so someone decided to seal it, and leave a plug in case they ever needed to drain the basement?? Maybe it connects to a perimeter drain sytem?? Someone suggested perhaps it was an old drywell which seemed odd to me but who knows. There are old water hookups in that area, and I believe at one point there was probably a washer and dryer there. Can't connect to a storm sewer as we don't have any. My sanitary sewer line runs out about 4' above the floor so it can't connect to that. It's about 4-5' from the end basement wall, and about 2-3' from the back wall (roughly). I started to chip away at the concrete at one point but decided that might not be a good idea. Of course I've tried to remove the plug without success as well. Pics below. Any Ideas??????