How would you define “water damage”? There doesn’t appear to be an industry standard as to what actually qualifies as “damage”? Is it a stain? Does the wood have to be rotted? Or something in between?
Example definition of damage from Google:
dam·age
ˈdamij/Submit
noun
1.
physical harm caused to something in such a way as to impair its value, usefulness, or normal function.
Depends a stain on a ceiling can be fixed easily after the problem was solved
A stain on roof decking or sub floor may be worst on The side that can not be viewed ,If rot is present that would be damage for sure
Depending the location a stain can be damage that later could later fail or would need replacement. It would depend on the situation. It would be a judgement call .
Stains are defects.
I report dry stains, wet stains and moisture damaged materials as defects.
Report what you see.