Water Line Leak Question

[Cass]

I was asked this question by a customer that buys, fixes and sells or rents out older homes, and I want to get some feed back on this.

Many of the homes he buys are occupied when he buys them. He will buy 1-5 at a time. The homes are 30s-50s vintage with galvanized water supply coming from the street. He has noticed that it seems like many of his homes will develop a leaking supply line, and require replacement, if the home sits empty for an extended period of time (4-6 months). The ones occupied seem to never develope a leak.

The question is will water in a galv. water line that is just sitting tend to be more corrosive than one being used or is it just his imagination and luck.

[hj]

Not likely, and yes. Most leaks underground develop from the outside in, so the ground is causing the leak, not the water.

[Verdeboy]

If all the empirical evidence points to leaks occurring much more frequently in pipes that have no moving water, I would tend to believe it. Then the question is why? It could simply be that water freezes a lot easier when it isn't moving. And, a frozen pipe will eventually leak. If it never gets that cold in your area, then we'll need an engineering type to figure it out.