# Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL - facts

Canonical page: https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes
Type: Lab article

## TL;DR

What size bac water to buy: match the vial to the mL you use in 28 days. 3 mL vs 10 mL vs 30 mL compared, with waste and cost per mL actually used.

## Facts Index

| Fact ID | Category | Entity | Attribute | Value | Source | Evidence |
|---|---|---|---|---|---|---|
| bacteriostatic-water-vial-sizes:title | identity | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | title | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:published | identity | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | published | 2026-10-27 | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:author | identity | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | author | PreppinPeppers Editorial Team | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:topics | identity | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | topics | bacteriostatic water, diluent, Guides, research | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:summary | content | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | summary | What size bac water to buy: match the vial to the mL you use in 28 days. 3 mL vs 10 mL vs 30 mL compared, with waste and cost per mL actually used. | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:section-1 | content | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | section | Why the 28-day window decides vial size | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:section-2 | content | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | section | Which vial size wastes least for your bench? | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:section-3 | content | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | section | What each size costs per ml you actually use | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:section-4 | content | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | section | Where a 10 ml vial fits | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:section-5 | content | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | section | Storage is the same for every size | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:section-7 | content | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | section | Related guides | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes |
| bacteriostatic-water-vial-sizes:product-bacteriostatic-water-3ml | products | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | references product | Bacteriostatic Water 3 ml Vial (Preppin' Peppers, USP Grade) | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/products/bacteriostatic-water-3ml |
| bacteriostatic-water-vial-sizes:product-bacteriostatic-water-30ml | products | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | references product | Bacteriostatic Water 30 ml Multi-Dose Vial (Pfizer Hospira, USP) | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://www.preppinpeppers.com/products/bacteriostatic-water-30ml |
| bacteriostatic-water-vial-sizes:source-dailymed-nlm-nih-gov | source | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | cites | Bacteriostatic Water for Injection, USP: FDA label on DailyMed, U.S. National Library of Medicine (0.9% benzyl alcohol, multiple-dose vial) - dailymed.nlm.nih.gov | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=87d6e9dc-fe3b-4593-ac9a-d7493d1959c7 |
| bacteriostatic-water-vial-sizes:source-dailymed-nlm-nih-gov-2 | source | Bacteriostatic water vial sizes: 3 mL vs 10 mL vs 30 mL | cites | FDA label (DailyMed): Sterile Water for Injection, USP (Cardinal Health) - single-dose container, no preservative - dailymed.nlm.nih.gov | Lab article (https://www.preppinpeppers.com/blogs/the-lab/bacteriostatic-water-vial-sizes) | https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=48d75a7c-8329-48a8-bea0-a8c144ddf637 |

## FAQ

### What size bacteriostatic water should I buy?

Match the vial to the water you will draw within 28 days of the first puncture. Up to about 3 ml in that window, a 3 ml vial wastes least; roughly 4 to 10 ml, a 10 ml vial or one 3 ml vial per reconstitution; more than 10 ml, a 30 ml vial.

### Is 10 ml or 30 ml bacteriostatic water better?

Neither is better in general. A 30 ml vial costs less per ml but only if most of it is drawn within 28 days of the first puncture. If you would draw 10 ml or less in that window, a 10 ml vial leaves less to discard.

### How many reconstitutions does a 3 ml vial cover?

One typical reconstitution of 1 to 3 ml. At 1 ml per reconstitution it covers up to three, as long as they all fall within 28 days of the first puncture.

### Why does the 28-day window decide vial size?

A multi-dose vial is commonly discarded 28 days after its first puncture, however much is left. Any water you have not drawn by then is thrown away, so a vial larger than your 28-day use is paying for water you discard.

### Does unopened bacteriostatic water need to be refrigerated?

No. Store unopened vials at room temperature, 68 to 77°F (20 to 25°C), out of direct sunlight, and never freeze them. Only the mixed solution goes in the fridge.

### Is the 3 ml vial the same formula as the 30 ml Hospira vial?

Both are bacteriostatic water with 0.9% benzyl alcohol as the preservative. They come from different makers and in different sizes: the 3 ml vial is our own Preppin' Peppers vial and the 30 ml vial is made by Pfizer Hospira.

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