On an average, the liver takes one hour to metabolize one ounce of alcohol. The amount of time that alcohol will still be in your system after a period of drinking depends on a lot of factors such as age, amount conumed, ethnicity, body fat content, how much food you have consumed before or during drinking, the fat content of the food consumed and any medications that the individual might be on.
On average a person with a healthy liver is going to see the alcohol clear from their blood after about 5 to 10 hours. However, alcohol will stay in urine anywhere from 12 to 36 hours after drinking )depending on the factors invovled).