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Reverse osmosis systems
RO is the most thorough treatment for dissolved contaminants — but it's usually a point-of-use fix for drinking water, not a whole-house system. Here's when it's the right tool.
Read this first
Reverse osmosis treats one tap and wastes some water doing it. It's the right call for nitrate, arsenic, and high TDS — not for whole-house scale or a sulfur smell. For those, see whole-house systems.
Where RO fits
Point of use
Under-sink RO
The most thorough option for nitrate, arsenic, lead, and TDS at one tap.
See picks →Contaminant
Arsenic removal
Why RO is the reliable fix, and how to confirm arsenic first.
Read the guide →Testing
Confirm it first
RO is overkill for taste alone. Test before you buy.
Testing guide →