How to Store Bacteriostatic Water Safely Confused about whether BAC water needs refrigeration after opening? According to USP standards and Pfizer's own guidance, both room temp (2025C) and refrigeration are acceptable 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 30ml Overnight Bacteriostatic Water SyringesNeedlesDepot Standard 100% Purity Bac Water 10 ml Vial