I asked a pharmacist and she told me 4-5 days. I was told by a pharmacist that valium and temazepam stay in the system for urine testing 4-5 days, please advise. Expert: nurse_Dan replied 8 years ago. If you are having a drug test valium is not a good drug to have in your system. It has a very long half life and can stay in your system up to 30 days. Ask Your Own Health Question. Customer: replied 8 years ago.