I assume you're asking about freeze damage at the water distribution pipes, right?
I've found that the damage has always been quite obvious; just look carefully at the water distribution pipes for any 'loose' sections of copper. Loose sections will look like sections of the copper were never soldered together; this is the most typical type of freeze damage you'll find.
The other type of freeze damage that I've found at copper tubing is where the pipe actually ruptures - click my link below to see a photo of what this looks like.
If a home has freeze damage, you'll almost always find signs of it near the water meter.
- Reuben - Mon Oct 25, 2010