Electric Water Heater Grounded to Copper Water Pipes?

I live in gulfcoast Florida and have been plagued by persistent (1-2 per year) pinhole leaks in the copper pipes in our home (1990). One interesting aspect is that, so far, all the pinhole leaks have occurred in cold-water lines. I am not sure what that may indicate, but, perhaps, someone has an opinion.
I have read many of the posts concerning the many theories for the causes of this problem, i.e., acicidity, electrical currents, chemicals, minerals, etc. Regarding possible electrolysis and stray electrical currents, I installed a new grounding rod on the main electrical box outside the house (right near where the water line enters, incidently). However, I noticed that my second-floor electric water heater is grounded to the copper piping adjacent to the heater. Having read a lot of posts commenting on the need to isolate electrical currents from the water system, why would a water heater be grounded to the water pipes? Does this make sense? Should it be changed?
Any suggestions for diagnosing and/or addressing this pinhole problem would be appreciated.
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the correct name) in it that is made to be eaten away by the chemicals in the water. It is a rod of special metel that is usually attached to a pipe plug that goes into the water of the tank. Saves the tank. By now yours is probably just about gone.
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The other poster had a good idea changing the anode in the water heater.
All appliances, loads should be grounded to the service by use of an conductor. Not by using a water pipe. Suggest you run a proper circuit to the water heater.
Stop guessing and try to find someone who has the equipment that can measure the ground system. Amec makes a meter for ~$2k. Measures both ohms and volts. Get a decent VOM meter and start taking some measurements. Sadly this could get really expensive to find.
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A plumber I see from time to time on different jobs once told me about bad copper piping coming out of Mexico. He said that on one job that he used the stuff many pinholes showed up after the system was pressurized. Perhaps you have crummy pipes. Do your neighbors have similar problems? You could also have your water tested to see if that is a contributing factor.
Regarding the upstairs water heater being grounded to the water pipe, I suggest that you leave it alone. It may not be a grounding connection, but it may be a bonding connection. I doubt that electrical current on your water pipes is causing the pin holes to develop.

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On Sat, 29 Oct 2005 22:04:52 -0400, "John Grabowski"

Everything other replies have said is true. Seriously, get your water tested. The cost is minimal. You want to find out how acidic your water is. Acidic water eats up pipes. If it is, you might want to replace your pipes with pvc. If all the leaks keep occuring in the same section of piping, it could just be bad pipe(s). In other words, bad from the factory. If this is the case adn your water is not too acidic. Just replace that entire section of pipe. The fact it's only happening to your cold pipes tells me that bad pipes are indicated in that part of the house.
One other thing, lightning. I have seen it happen first hand. A bolt of lightning hits in the area, travels down a copper pipe, and blows a small hole in the pipe (usually right near a turn in the pipe). This is an actual problem that really does occur in rare cases, (but not as rare as I once thought, because I have seen it happen several times now).
GROUND that water heater with WIRE. Use #6 or thicker wire and run it to your ground rods. The copper pipes are already grounded to the water heater anyhow, unless they are isolated by dielectric unions. Bond the pipes WITH WIRE to the ground rods too. That also helps with lightning strikes.
One last thing to look at. Do you have a combination of copper and steel pipe? Or have copper touching aluminum or other metals somewhere in the system? All of that can cause corrosion. If connected to steel pipes, use dielectric unions. If touching other metals, place plastic or tape in between.....
Mark
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Many thanks for your suggestions and those of all others, too. Will conduct further investigation and implement suggested solutions. Thanks again.
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