This is the inside of the garage that has had water damage in the roof wall area. How would you determine if this is current damage or past damage? Maybe use a moisture meter? The owner says that the rubber roof has been replaced about 4-5 years ago and the issue has been corrected. The ceiling in the garage is a foam material. Thanks for any help!
By the way they installed the drip edge on top of the rubber, it is probably still leaking. :roll:
Note what you see.
If it has indeed been “Corrected” perhaps there is some documentation verifying this and a warranty of sorts.
Or you could run a hose up there and look for moisture. 
Yeah Larry I saw that too. I think it was a handyman special.
hhahahhah, now I look again that is just dumb, pounding nails through a Foam Roof…
Once again, note what you see. 
The simple answer is to note what you see, flashing over the top of the rubber and visible moisture stains. A moisture meter in this area would have been a good idea to check the ceiling and wall area. I agree with Larry, it is probably still leaking.
This is a fully adhered EPDM system and was not done by a professional licensed for this work.
Fully adhere systems should have the fiberboard underneath the roofing membrane attached with screws and plate washers as you can see in the photo. Problem is, there needs to be about 12+ per 4x8 sheet.
The roof edge flashing was installed wrong and I assumme that at least the rubber is fastened to the vertical edge. They use the wrong type of fastners and not flashed per Manufactures detail.
Here is a typical detail of the same.
http://www.carlisle-syntec.com/documents/ResLib/07_X3FB-1C.pdf
The leakage could very well be old per the dried up stains on the drywall and the staining from the bead board on the ceiling is from wood and rust stains that bled through.
I certainly would have recommended a Certified Licensed roofer to inspect and evaluate the cost of repairs. 