Buying guide · checked 8 October 2026
Do you need a prescription for bac water?
At a pharmacy, usually yes. Bacteriostatic water for injection is labelled "Rx only", so pharmacies such as CVS, Walgreens and Walmart treat it as a prescription item sold at the counter, not over the counter. Online, Direct Bac Water does not ask for a prescription at checkout and sells it for laboratory research and the reconstitution of legal, physician-prescribed medications only.
Bac water (bacteriostatic water) is sterile water with 0.9% benzyl alcohol (9 mg/mL), a preservative that lets one vial be drawn from more than once. This page explains what "Rx only" means for buyers, what pharmacies charge, and the difference between pharmacy and online purchase.
Is bacteriostatic water over the counter?
No. The FDA label for Hospira Bacteriostatic Water for Injection, USP carries "Rx only" on its vial and tray panels. "Rx only" is the federal legend for a prescription drug, which is why you will not find bacteriostatic water for injection on a pharmacy shelf. The label also warns "NOT FOR USE IN NEONATES", because benzyl alcohol is unsafe for newborns.
What pharmacies charge for bac water
Pharmacies fill bacteriostatic water for injection at the counter and do not publish a shelf price. Price-comparison sites put the average US retail cash price of a 30 mL vial at $23.76 (GoodRx) and $28.79 (Rx.com), and published price guides quote up to about $35, so expect roughly $24–$35 a vial with a prescription. Each pharmacy has its own guide:
Pharmacy vs online: what changes
| Pharmacy | Direct Bac Water (online) | |
|---|---|---|
| Prescription | Expected | Not asked at checkout; sold for laboratory research and the reconstitution of legal, physician-prescribed medications only |
| Stock | Varies by store; often ordered in | 3 mL, 10 mL, 30 mL and Hospira 30 mL held in US stock |
| 30 mL vial | about $24–$35 cash price | $18.95; $14.00 a vial in a 10-pack |
| Packs | Usually single vials | Packs of 3, 5, 10, 25 and 100 |
| Delivery | Collect in store | Same-day dispatch before 1 pm ET (Mon–Fri); 2–5 business days standard, free over $200 |
Buying bac water from Direct Bac Water
Direct Bac Water sells US-made bacteriostatic water online from $6.50 a vial. Checkout accepts Apple Pay, Google Pay, credit and debit cards, and Zelle, and orders placed before 1 pm Eastern Time on a weekday ship the same business day by UPS or USPS.
Prescriptions and bac water: questions
Can you buy bacteriostatic water over the counter?
Not at a pharmacy. Bacteriostatic water for injection is labelled "Rx only", the federal legend for a prescription drug, so pharmacies sell it at the counter, usually against a prescription.
What does "Rx only" mean on bac water?
It is the FDA-required legend marking a prescription drug: the product is to be dispensed on a prescriber's order. It appears on the Hospira bacteriostatic water vial and tray labels.
How much does bac water cost at a pharmacy?
Expect a cash price of roughly $24 to $35 for a 30 mL vial. GoodRx puts the average US retail price at $23.76 and Rx.com at $28.79 (checked 8 October 2026).
Does Direct Bac Water ask for a prescription?
No. Direct Bac Water does not ask for a prescription at checkout. It sells bacteriostatic water for laboratory research and for the reconstitution of legal, physician-prescribed medications only.
Why does bac water say not for use in neonates?
Benzyl alcohol, the preservative in bacteriostatic water, can be toxic to newborns, so the label warns against use in neonates and preservative-free water is used for them instead.
Sources
- U.S. National Library of Medicine, DailyMed: Bacteriostatic Water for Injection, USP (Hospira, Inc.), package label and contraindications. Checked 8 October 2026.
- GoodRx: average retail price of bacteriostatic water, $23.76. Checked 8 October 2026.
- Rx.com: retail price of bacteriostatic water, $28.79. Checked 8 October 2026.
- Published pharmacy price guides quoting up to about $35 for a 30 mL vial without a discount, 2026.
This page is re-checked every month. Next review: 21 November 2026.