There is no true substitute for sterile water; though there are many ways to make water sterile. It may be helpful to know what the reason is for the use.... I'd suggest asking your question with more detail. Best wishes.
To sterilize completely, instead of just rendering aseptic conditions to instruments or surfaces used in medicine or scientific experimentation.
It was used to sterilize the instruments and sheets and towels that were going to be used to touch the baby.
An autoclave is used to sterilize medical instruments. They have a reservoir to hold the distilled water that is pumped or drained into the chamber.
UV light radiation kills bacteria and can sterilize utensils (UV rays are used to sterilize goggles in the laboratory, for example.
steam
To sterilize instruments.
In many experiments, buffers are used instead of water becuase buffers control pH, whereas water does not.
gamma rays
Filtration: used to sterilize heat sensitive materials such as vaccines
handpiece should be sterilize after using on each patient.
glass.
heavy fuel oil can be ssed instead of diesel.