Buying bacteriostatic water is not complicated, but there are five decisions to make and a few checks to do, and getting them right the first time avoids the two common outcomes of getting them wrong: vials that expire unopened, and opened vials that pass 28 days half full. This guide walks through the decisions in order.
1. Choose the vial size
Bacteriostatic water comes in 3 mL, 10 mL and 30 mL vials. The rule is to choose the smallest size that will be used up within 28 days of opening, because that is the in-use limit for an opened vial. A laboratory that draws 0.5 mL twice a week wants 3 mL vials; one that draws 2 mL a day wants 30 mL vials. The vial-size recommender works this out from a usage estimate. See 3 mL vs. 10 mL vs. 30 mL.
2. Choose the pack count
Packs of 4, 8, 12, 24 and 36 vials cover monthly usage from a single bench to a departmental stockroom. Larger packs cost less per vial, but only if the vials are used before they expire; two to three years of shelf life is generous, so for most laboratories the larger pack is the better value. See pack sizes explained and how to estimate monthly usage.
3. Ask for the documentation
- Certificate of analysis for the lot: sterility, endotoxin, pH, particulates, benzyl alcohol assay and expiry. See how to read a COA.
- Safety data sheet for the product, kept with the laboratory’s chemical inventory. See reading the SDS.
- For institutional purchasing, the supplier’s details for the approved-supplier file. See documentation in GLP and ISO/IEC 17025 laboratories.
4. Check on arrival
Count the vials, match the lot number and expiration date on the carton to the vials, confirm the label reads bacteriostatic water with 0.9% benzyl alcohol (not bacteriostatic sodium chloride), check every vial for an intact crimp and cap and for clear, colorless, particle-free contents, and record the receipt. The printable receiving checklist covers all of it in one page.
5. Store correctly
Controlled room temperature, 20–25 °C, protected from freezing, in the carton, with the earliest expiration date used first. Opened vials are dated and discarded 28 days later. See how to store bacteriostatic water, the printable temperature log and the printable opened-vial log.
Comparing suppliers on true cost
The price per vial is the wrong number to compare. The right one is cost per millilitre actually used, which depends on the vial size, how much of each vial is used before its 28-day discard date, and shipping. A 30 mL vial at a low price per millilitre is expensive if a third of it is discarded; a 3 mL vial at a high price per millilitre is cheap if every drop is used. The cost-per-mL-used calculator compares options on that basis. See also what determines the cost per vial.
Ordering from BAC Water Supply
All packs are listed on the shop page with vial size and pack count in the product name. Orders ship from U.S. stock with free shipping over $75, and larger or recurring requirements go through the bulk and wholesale inquiry page. Lot numbers and certificates of analysis are available on request through the contact page.
Related
Where laboratories buy bacteriostatic water · Buying in bulk: a procurement checklist · Bacteriostatic water FAQ
All BAC Water Supply products are supplied for laboratory research use only and are not for human or veterinary use.