How long does it take for meth to not be detected in urine?

What's the concern?: Rather than give an answer to your question, i'd raise another: what's the concern about having meth detected? If it's to avoid being discovered that you're taking meth, and a doctor isn't prescribing it, then you have a drug problem, so seek help. If a doctor is prescribing meth and you feel the need to avoid it's detection [eg, an employment drug screen], then discuss this with your doctor.