You should read my post How long did it take you to clean out naturally. For me it took 60 days until my urine was clean. I tested positive at day 35, 42, and on day 52 got my first faint line. I am a chronic user, I smoke multiple times a day and have for over 15 years. On day 60 I tested my first piss of the morning and had a line as dark as the control line. So 30 days is some bull for a chronic user, unless you are skinny and have no body fat, and work out all the time.