Re: Reaccurring Pinhole leaks - Other things to check.
Here are some other places to look for your problem. While agressive water may be the cause, there are other places to look.
Do you have a softener? If so, and it is set to zero or close to zero hardness, it may be making the water agressive. See if you can run the finished hardness at about 8 - 10 grains.
Do you have any type of an alarm system. If they grounded the alarm system to the water pipes, the d.c. current from the alarm can attack copper.
Anything else using the water pipes for a ground? Lighting, washer, dryer, doorbell? Take it all off and run ground wires.
Do you have a ground rod? If you whole house is grounded to the water pipe by your meter, is it jumpered across the meter? Appliances attached to the water pipes in the house need a connection to ground, if the meter fittings are not installed prolerly they may insulate the house from the ground. There should be a jumper wire around the meter. A ground rod is better.
Is the water heater plumbed correctly? Do you have a bi-metalic connector on each water line? If not you need them.
Waste not, want not.
Use it up. Wear it out. Make it due, or due without.