[4] A non-sterile version may be used in manufacturing with sterilization occurring later in the production process.

[5] The primary use of sterile water for injection is as an ingredient for dilution of other medications (aseptic preparation of parenteral solutions).

[6] If it is given by injection into a vein without making it approximately isotonic, breakdown of red blood cells may occur.

[4] Water for injection is generally made by distillation or reverse osmosis.

[5] In the UK, some hospitals offer subcutaneous injections of water directly for treating back pain in labour.