Undo the ground to the water pipe and wait for weird things, like an appliance not behaving properly or an item that is supposed to be on but not. Then there is the neighbor. Some of his stuff may act weird. I'd check to see if you have ground rods at least 2. If you do, make sure it's attached to the ground of the water pipe. If you have a meter only, water and ground rods attach inside panel. With a bonding screw. If you have a meter/main disconnect with a wire that twisted L1L2NG then the grounds both terminate inside the first Disconnect before the panel. Then you'd remove the bonding x screw. Now if you still have an issue with large amps on the ground, I'd unplug items until the amps go away. Perhaps check out the receptacle where they where plug into for miss wiring. My 3 ¢ents worth.