The filtration technology can be similar, but the ownership experience is different.
Countertop RO
- Usually easier to install.
- Useful for renters or people who do not want plumbing changes.
- Uses valuable countertop space.
- May require manual filling or emptying depending on design.
Under-sink RO
- Keeps the main appliance out of sight.
- Can provide a dedicated filtered-water tap.
- Usually involves more installation.
- Requires access beneath the sink for maintenance.
Which should you choose?
Think about permanence, available space, installation tolerance and how frequently the system will be used. Neither format is automatically superior for every kitchen.