Quick answer
Which water do I use to reconstitute?
For most reconstitution, bacteriostatic water is the default; sterile water is the single-use alternative.
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Quick answer
Bacteriostatic water is sterile water with a little benzyl alcohol that suppresses bacteria, so a multi-use vial stays usable for weeks in the fridge. Plain sterile water has no preservative — fine for single use, but it spoils faster once opened. Tap or distilled water is never used.
Full detail: bacteriostatic vs sterile water.
Frequently asked questions
Is bacteriostatic water always best?
For multi-use vials, yes — it lasts longer. Single-use scenarios or a benzyl-alcohol sensitivity are the main reasons to use plain sterile water.