The water pipes in our mobile home have begun to vibrate and make a pumping sound whenever water is turned on anywhere. We have had a plumber twice. Once he did something at the box at the street, but that only helped for a matter of hours. He came again and did something with the pressure valve where the water shutoff is in the house. That also helped for a very short time, but now the problem seems to be getting worse. He seems to be at a loss as to what to do. Any suggestions?