Yes, reverse osmosis (RO) is effective at removing bacteria from water. The semi-permeable membrane used in the filter has very small pores that allow water molecules to pass through while blocking the passage of larger molecules, including bacteria.

Reverse osmosis can effectively remove a wide range of impurities, including bacteria, viruses, ions, and other contaminants. The size of the pores in the membrane is typically in the range of 0.0001 microns, which is small enough to block the passage of most bacteria.

It's important to note that while reverse osmosis is effective against bacteria, its efficiency in removing other contaminants may vary. Some smaller molecules and certain gases may not be effectively removed by the standard RO process, so additional filtration steps or technologies may be needed for comprehensive water purification.