I was using the sink the other night and I got a little charge from the water. When I went to home depot they told me to make sure ground my hot water heater (witch is gas).I did not that and I still get a charge so I took a ground wire from the faucet handle to the drain and I got a pop then about a minute later I did it again and I got like a series of pops and now I don't get shocked, there is not voltage on the line at all and I was wondering what might cause this problem. I am running a ground from my drain line to the groun d in the electrical panel witch I am hoping that will take care of the problem.

A cable is touching a part of the metal plumbing, which may be insulated with PVC sections or fittings, and energizing it. Or an appliance is shorted but not grounded properly.

Don't just ground the pipe, look for this fault and correct it.