I got called to a customers island house on the 4th because they were getting shocked off the outside water spigots. Customer was barefoot, standing in a puddle, showing me where he feels a shock. I used a meter instead. Two outside water spigots, both had voltage to ground, 7 volts on one, 14 on the other. The spigot with 7 volts was 5 feet from the 2 ground rods at the service entrance. I shut off power to the house(meter/disconnect) and nothing changed. I told customer I would contact utility about a possible neutral issue and suggested he stay away from tie spigots until the power company checked it out.
I called the power company the next day and spoke with the head lineman. After explaining the situation he started giving me grief for grounding the water pipes and if I hadn't this problem wouldn't happen! So, I had to explain to the head lineman why we bond water lines along with other things, then explain why this voltage is happening, why I felt it was a power company issue and he needed to go and check things out. He finally agreed to go look, but I don't have high hopes for a solution from them.
While in the shower last night and thinking about this an idea came to me. If I were to purchase a couple of 4x8 sheets of stainless steel expanded metal grill and bury one under each spigot, attach a #6 solid bond wire from the metal grill to the water spigot above, I think my shock potential would go away. There would be no way to contact the water spigot with out standing on the metal grid ( which would only be a couple of inches below grade).
Just throwing this problem/solution out there for feed back before I pitch it to the home owner. Has anybody had a similar problem and what did you do? I don't have high hopes for a power company solution and want to be sure my customer and the army of kids around stay safe. While the 7 to 14 volts may not be lethal, my opinion is it shouldn't be there at all and could it all of a sudden get worse.
I would beef up the ground electrode system and be sure all of the connections are tight. It is not unusual that the "neutral" from the utility is not really "ground". The only fix is to try to be sure "ground" is as close to earth potential as you can at the home. I would certainly start by checking the ground clamps on the rods. I was getting bit when I first moved in here and I made it a whole lot better, just by replacing the clamps.
If you have wye distribution you will always have stray voltage. It just can't be avoided. The voltage drop in the PoCo neutral is going to show up on the grounding conductors, throughout the system. I have about 3a on my neutral to the PoCo through my GES with the power off. My GES may be the best ground electrode on my street tho. I just try to be sure everything around the house is bonded to my "ground" so I don't have gradients. You can have all the electrodes you want, as long as they are bonded together with the appropriate conductors. I am a fan of "the more the better". I have 6 rods around the house, 2 "building" Ufers and the King Kong of all Ufers, an in ground concrete pool.