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Short answer: “Sterilised water” (UK spelling) and “sterilized water” (US spelling) describe water that has been through a sterilising step. On a product label the working term is “sterile water”, and the Sterile Water for Injection, USP labels from B. Braun and Baxter add that it is nonpyrogenic and has no antimicrobial agent added. It is not isotonic: both labels describe it as hypotonic, and the Baxter label calls it a hemolytic agent.
General product information only, not medical advice. Always follow the product label and your facility’s protocols.
Definition and scope: sterilised, sterilized and sterile water
The two spellings, “sterilised” and “sterilized”, name the same process word. Searchers using either are usually after the same thing, and so are those asking “sterile water meaning”. The label-level product name is different: the labels cited on this page are titled “Sterile Water for Injection, USP”. For the broader product guide, including injection and irrigation forms, see what is sterile water.
What is considered sterile water?
The B. Braun Sterile Water for Injection USP label on DailyMed states: “It is sterile, hypotonic, nonpyrogenic, and contains no bacteriostatic or antimicrobial agents.” The Baxter Pharmacy Bulk Package label on Drugs@FDA (a 2016 label PDF that FDA notes may not be the latest approved) describes “sterile, nonpyrogenic, distilled water” and states “No antimicrobial or other substance has been added.” So on these labels, “sterile water” means three things together: sterile, nonpyrogenic, and nothing added. Sterilising steps used in laboratories are a separate topic; see filtration sterilization and autoclave sterilization temperature.
Is sterile water isotonic?
No. Both labels describe it as hypotonic. The B. Braun label carries the warning “Hypotonic and hemolytic”. The Baxter pharmacy bulk package label gives a calculated osmolarity of 0 mOsmol/L and calls the product “a hemolytic agent due to its hypotonicity”. For the isotonic comparison, see what is 0.9% sodium chloride and normal saline concentration.
What the label states: a decoder
The table lists phrases from the two labels cited in the Sources section. It does not describe every product on the market.
| Label wording | What the labels say |
|---|---|
| Sterile | Stated on both labels (B. Braun: “It is sterile”) |
| Nonpyrogenic | Stated on both labels |
| No antimicrobial added | B. Braun: “contains no bacteriostatic or antimicrobial agents”; Baxter: “No antimicrobial or other substance has been added” |
| Hypotonic / osmolarity | B. Braun: “Hypotonic and hemolytic”; Baxter: 0 mOsmol/L (calculated) |
| pH | Both: 5.5 (5.0 to 7.0) |
| Container | B. Braun: single dose container; Baxter: Pharmacy Bulk Package, titled “Not for Direct Infusion” |
| Distilled | The Baxter label describes the contents as “distilled water”; distilled describes the source water, sterile describes the finished product |
Where it matters for labs, clinics and supply decisions
A supplier document or product label is easier to read once you know which of these items it states. A checklist built from the label fields above: sterility statement, nonpyrogenic statement, whether any antimicrobial is added, container type (single dose or bulk package), pH range, and osmolarity or tonicity wording. If a document leaves one of these out, check the product’s own labelling or ask the supplier rather than assuming. Distilled or deionised water sold for lab use is a separate product category; the distilled versus sterile water comparison sets them side by side.
Common misunderstandings
- “Sterile means isotonic.” The labels say otherwise: sterile water is hypotonic, with a calculated osmolarity of 0 mOsmol/L on the Baxter label.
- “Sterilised water and sterile water are different products.” The spelling differs by region; on these labels the product name is Sterile Water for Injection, USP.
- “Sterile water has a preservative.” Both labels state that no antimicrobial agent is added.
- “Distilled means sterile.” The Baxter label lists “sterile, nonpyrogenic, distilled water”; sterility is a separate stated property.
FAQ
What is sterilised water?
Water that has been sterilised, UK spelling. On product labels it appears as sterile water: sterile, nonpyrogenic, with no antimicrobial agent added.
What is sterilized water?
The US spelling of the same term, with the same label meaning described above.
What does sterile water mean?
On these labels, it means water that is sterile and nonpyrogenic with nothing added. See what is sterile water for forms and types.
Is sterile water isotonic?
No. The labels describe it as hypotonic, and the Baxter label calls it a hemolytic agent due to its hypotonicity.
Sources
Checked 2026-11-01.
- DailyMed, B. Braun Sterile Water for Injection USP label: https://dailymed.nlm.nih.gov/dailymed/fda/fdaDrugXsl.cfm?setid=8fc8d87a-3951-4ac5-97df-c161ffc90475&type=display
- FDA Drugs@FDA, Baxter Sterile Water for Injection USP Pharmacy Bulk Package label (2016): https://www.accessdata.fda.gov/drugsatfda_docs/label/2016/018632s051lbl.pdf
