The degree and location of the clog, as well as the technique employed to clear the drain, can all affect how long it takes a plumber to unclog a drain. A plumber may be able to unclog the drain in as little as 15 to 30 minutes for simple clogs like those brought on by hair or soap buildup. More difficult clogs, however, might take several hours or even several visits to completely clear. It's crucial to work with a plumber who is qualified, experienced, and able to accurately assess the situation and estimate the required time and cost.