The symptom: When running water from the kitchen or bathroom faucet, every 3-5 seconds there is a split second of flow interruption with an accompanying bang/shudder heard/felt in the supply lines. The faucets have separate hot/cold handles... the symptom occurs in either case - when running hot water or when running cold water. I do not detect the symptom when running the shower or when the toilet tank is filling. Background: This is occurring at our cabin. During the winter months, we completely drain the supply lines and the water heater. However, this problem originated since the return of warmer weather. We do turn off the main supply line year round when we are not there; and the cabin can sit unused for a few weeks on end. Any help/guidance is appreciated.