Sterile water for injection is a sterile, non-pyrogenic preparation that contains physical, chemical, and biological qualities suitable for parenteral administration. It is composed of purified water and has a total solids concentration not greater than 10 mg/L. It may contain an appropriate solubilizing agent and/or antimicrobial preservative(s). 

It is cleared of all microorganisms through a series of filtration processes such as membrane filtration, ultrafiltration, and diafiltration. The water is also passed through a bacteria-retentive filter with an absolute pore size of 0.2 microns or smaller, which is capable of removing all bacteria and other microorganisms.