These pics are from my sisters house. This is an opening about 1 1/2 inches that opens to about 3-4 inches and is about 15 inches deep. The lip is threaded, and about 2 inches below the lip is an opening in the side. When we get a heavy rain she gets water bubbling out of the hole onto the floor. I suggested that she cap it. But I am wondering about the purpose of the hole. The house is over 100 years old and was a farm house at one time. She does have a sump that was installed many years ago but is not attatched to a drain system, it just collects what flows through the ground.