there is a valve on your system thet keeps water from rushing back down the well. Depending on what type of system you have it could be a foot valve or a check valve. It sounds like that valve is not closing fast enough and is allowing some of the water back down the well. Do you have a submersible pump or a jet pump? With a submersible pump you would only see the tank in the basement with a pressure switch mounted on the front of it. If you have a jet pump its most likely in your basement. A deep well jet pump will have 2 pipes going into the front and a shallow well jet pump will have 1.