Up to 10 days. For most individuals having used the substance, the general consensus is often noted as a maximum of 10 days that methamphetamine remains detectable via a urine drug test. Often it is more like 3-5 days. The urine test rarely gives an incorrect finding if meth is in there. It can be detected in hair for much much longer. Meth is highly addictive, dangerous & harmful to mental and physical health.