How long does valiums or somas last in your system?

It can stay in your urine from 1 - 42 days depending on your usage and your metabolism. If they are prescribed for you there should be no problem, if you can prove the prescription.

Like J-9 said if your using them legitimately, all should be OK, there are a lot of factors involved with figures, like the strength of dosage, quantity, frequency of use, your tolerance, sex, age, weight, overall health, metabolic state, but what I learned was it can be detected in your blood for approximately 20-100 hrs. and in your urine up to, and beyond, 14- days to 6 weeks, according to your usage.