All I know about my water system is that it is a submersible pump, the bladder tank is a clayton mark 80-03, pressure switch is a 30/50. The line from the well is 1 inch but has been plumbed with 3/4 copper between the check valve and tank t. The noise is only when the pump starts, starts off relatively mild and gets to max after about an hour or so. Sometimes starts right away. We have had the house for 6 years and last year was the first time it developed it's voice. You could always hear a slight noise when the pump came on but it certainly didn't get your attention. Placing my hand and ear on various components seems to point to the check valve.

Any ideas?