I drank one glass of wine on Thursday at 8:30 PM and I have a alcohol urine test today (Friday)at 2:30 PM. So there will be an 18 hour gap from when I had that glass of wine and the urine test. Will the glass of wine show up in my system? Can I do anything to remove it from my system like drink a lot of water, exercise or both?

Laregly dependent on the type UA. Test for ethanol would be negative at 18 hours after one drink. EtG (a metabolite of ethanol) testing could be positive. The detection window for one drink ranges from 3-30 hours. There is no way of predicting however.

There is a good chance, even with EtG that it might not be detectable based on the small amount consumed.