I had one beer at 9:00 last night. Had to take a standard EtOh urine test (not EtG) at 5 pm (about 18 hours after the beer). I had not gone to the bathroom since before drinking. I have had about 20 ounces of fluids since the beer.

Alcohol can show up in your system for up to 24 hours after the fact and probably longer if you've had an excessive amount. Granted, one beer is certainly not an excessive amount but 18 hours is not a long time either, so you're walking a close line. What is the purpose of this upcoming urine test and why do you need to conceal the fact that you've had one beer?

I deank about 18 ounces of beer 18 hours ago will it show up in test/ I also weigh 200pounds

Will 2 12 ounce beer show up in drug test `18 hours later

I had one beer at 9:00 last night. Had to take a standard EtOh urine test (not EtG) at 5 pm (about 18 hours after the beer). I had not gone to the bathroom since before drinking. I have had about 20 ounces of fluids since the beer.

Average elimination would be .015 ph. One beer (5%) would create a BAC of .023 (peak). Assuming lowest metabolic rate (Male .01) and maximum BAC (Female .025) ethanol is eliminated in under 3 hours. Add to this that UAT immunoassays typically have a cutoff of .02 (will not detect below), and more sophisticated instrumentation simply isn't employed for EtOH testing and you're safe from all directions.