The above listed are all valid possibilites for pin hole leaks. Our neighborhood of 400 has had 60+ pin hole failures just this year (2000). The home range from 12-20 years old, and all have failed at the same time! There are also failures in 4 surrounding subdivisions. We strongly believe the problem to be the Water Company. Our best educated guess so far is over chlorination of the water. Halides (chlorine, florine, bromine, etc) are aggressive to yellow metals (brass, copper, bronze). We are going to have several pipes tested by a metallurgical lab to positively identify the corrosion mechanism. Just another possibility….but check other neighbors, you may not be alone, and if so, it’s possible that it’s you water supplier.