RO removes bacteria. Like, e. coli and salmonella. The membrane pores are smaller than the bugs themselves. So they get trapped. Same for viruses and parasites. Think of it as a bouncer at a club—no microscopic freeloaders allowed.
Do Reverse Osmosis Filters Remove Chlorine at Michiko Durbin blog
But here’s the catch: RO isn't perfect for volatile organic compounds (VOCs). Those are things like pesticides or industrial chemicals that are tiny and love to dissolve. Most RO systems add a carbon filter beforehand to catch those. So, it’s a team effort.
The Stuff It Leaves Alone
Dissolved gases like oxygen and carbon dioxide? RO can’t remove them. They slip right through. That’s why RO water can taste a bit flat at first. It’s missing the fizz of life. Also, some small molecules like certain drugs or microplastics? Yeah, they can sneak past. Most modern systems have upgrades for that, though.
Oh, and water itself. Obviously. RO doesn’t remove the water. That would be awkward. (Though imagine the horror of a glass of nothing.)
