Unfortunately there is no simple answer to this question. The exact time will depend upon a variety of different factors such as the health of the person, the type of test conducted and the strength and history of previous consumption of the drug.
Usually, Clonazepam (Klonopin) can be detected in urine for approximately 3-8 days after the last dose taken but the duration may vary as I mentioned before.
I hope this helps.
Please feel free to discuss further if you have any doubt / query.