After last use, how long can marijuana be detectable in urine?

Dear Ask The Doctor: I haven't smoked marijuana in three months...if I smoke one blunt how long will it take to clean my urine

Dear Kevin: Marijuana can still be detectable for ~2 weeks before it gets cleared in the urine. If you were a heavy user, it may still be detectable for 3 months or so. I do hope I have answered your question and take care always.