How to Store Bacteriostatic Water
- Store sealed vials at room temperature, away from direct light — no refrigeration needed.
- Swab the rubber stopper with an alcohol swab before every withdrawal.
- Keep the vial sealed between withdrawals and handle the contents aseptically.
- Check the printed expiry date and use stock in date order.
The whole advantage of bacteriostatic water is that one sealed vial can be used again and again — provided you store and handle it correctly. Get it right and a single multi-dose vial serves you across many withdrawals. Here is exactly how to store bacteriostatic water before and after opening, and how to keep the contents protected for as long as possible.
Before opening
An unopened vial of bacteriostatic water is easy: store it at room temperature, away from direct light, and keep it sealed until you need it. There is no need to refrigerate it. Just check the printed expiry date and use stock in date order.
After the first puncture
Once you puncture the stopper, keep the vial sealed between withdrawals and stored at room temperature, away from light. The 0.9% benzyl alcohol preservative is doing the work of inhibiting bacterial growth (more on that in our benzyl alcohol explainer), which is what allows the same vial to be entered repeatedly. Clean technique is what lets it keep protecting the contents — so the handling steps below matter more than anything else.
| Stage | Storage | Guide |
|---|---|---|
| Unopened | Room temperature, away from light | Printed expiry date |
| After first puncture | Room temperature, sealed between uses | Use while clear; follow printed expiry |
Aseptic handling, step by step
- Wipe the stopper with a fresh alcohol swab before every single withdrawal — not just the first.
- Use a clean needle each time; never re-insert a used needle into the vial.
- Re-seal immediately after withdrawing and store it away from light.
- Inspect before use — the solution should be clear and colourless. Discard if it is cloudy, discoloured, or has visible particles.
Common mistakes
- Skipping the alcohol swab on later withdrawals because the vial "was clean last time."
- Re-inserting a used needle into the vial instead of using a fresh one each time.
- Using a vial without inspecting it — always check it is clear and colourless first.
- Using preservative-free sterile water as if it were multi-dose — it has no preservative, so it is single-use. See bacteriostatic vs sterile water.
Stock up on sealed multi-dose vials
Sterile-filtered bacteriostatic water — fast dispatch from Melbourne with express shipping.
View the product →Frequently asked questions
How long does bacteriostatic water last after opening?
Because it contains a bacteriostatic preservative, a sealed vial can be accessed repeatedly. Keep it sealed between withdrawals, handle it aseptically, and follow the printed expiry date — and discard it if the solution ever turns cloudy or discoloured.
Does bacteriostatic water need to be refrigerated?
No. Store it at room temperature away from light, both before and after opening. The 0.9% benzyl alcohol preservative is what inhibits bacterial growth.
Can bacteriostatic water expire?
Yes — use it by the printed expiry date on the vial, and always inspect it before use.
All products supplied by Aus BAC Supply are for laboratory and research use only — not a therapeutic good and not for human or veterinary use. This article is general product information and is not medical advice.