What does reverse osmosis remove?

Reverse osmosis uses pressure to move water through a membrane. It can reduce many dissolved substances, but the exact performance of a home system depends on its design and verified reduction claims.

Technology is only part of the answer

It is tempting to treat every RO system as if it removes the same list of contaminants. Product certifications and performance data can differ by model. If lead, fluoride, PFAS, arsenic, or another specific contaminant is your concern, verify that claim for the exact system.

Do not use TDS as a complete safety test

TDS measures the amount of dissolved material in water. It does not tell you which substances are present. A low or high TDS reading by itself is not a complete water quality assessment.

Read our TDS guide or learn how to choose a filter.