In the old days when water supplies were not reliably clean, it made sense to sterilize baby bottles. But now, sterilizing bottles, nipples, and water is mostly unnecessary.

Unless your water supply is suspected to harbor contaminated bacteria, it is as safe for your baby as it is for you. There is no reason to sterilize what is already safe.

Sterilizing the bottles and nipples is also unwarranted. Thorough cleaning with soap and water gets rid of almost all germs. And once on the bottle, the nipple begins to pick up all the germs in the environment, so a "sterile" nipple and bottle is just a pipe dream anyway.