Bottled water often carries an expiration or best by date, but pure water itself does not expire or spoil, as it lacks nutrients for bacteria growth. The date primarily concerns the plastic bottle: Bacteriostatic Water Suppliers: Sterile Water, Syringes & More Bacteriostaticwater.com Should I toss an unopened BAC water vial that expired a year ago? : r Peptidesource Bac Water Expiration Pfizer Hospira Bacteriostatic Water 30 mL Peptide Test