what.s the diff. between bacteriostatic water and sterile water??

From http://www.drugs.com/pro/bacteriostatic-water-for-injection.html
"Bacteriostatic Water for Injection, USP is a sterile, nonpyrogenic preparation of water for injection containing 0.9% (9 mg/mL) of benzyl alcohol added as a bacteriostatic preservative. "

ie. Bacteriostatic water is sterile water which contains a bacteriostatic preservative

From http://www.drugs.com/pro/sterile-water-for-injection.html
Sterile Water for Injection, USP is a sterile, nonpyrogenic preparation of water for injection, which contains no bacteriostat, antimicrobial agent or added buffer.
(Nonpyrogenic - will not cause fever)

Sterile water and Bacteriostatic Water are made in special laboratories and are often used as a diluent for injections.