Reverse osmosis for drinking water
A reverse osmosis (RO) system usually sits under the kitchen sink and supplies a separate drinking-water faucet. It pushes water through a fine membrane plus pre- and post-filters.
What to know
- RO treats water at one tap, not the whole house.
- Filters and the membrane need periodic replacement.
- RO systems send some water to the drain as part of normal operation.
- What a specific unit reduces depends on its certification. Ask for the model number and check it.
The U.S. EPA explains how to find filters certified for specific contaminants: EPA guidance on certified filters.