Is reverse osmosis water good for you? What the sources say

The short answer

Whether any water is good for you is a health question, and health questions belong with your doctor. What the sources can tell you is narrower and more useful: what RO can take out of water, what is in your water to begin with, and how to check that a system does what it claims.

What RO can take out

The EPA’s WaterSense program says reverse osmosis systems can potentially remove water contaminants such as lead, volatile organic compounds (VOCs), PFAS, arsenic, bacteria and viruses. If one of those is in your water at a level you are concerned about, RO is one of the treatments worth asking about.

Two words in that sentence matter. Potentially, because a given system’s results can depend on its design, its certification and its upkeep. And such as, because the list is examples, not a guarantee for every substance. The Texas Commission on Environmental Quality’s advice is the practical test: select a unit certified by NSF, Underwriter’s Laboratory or the Water Quality Association to remove the specific contaminant you are concerned about.

What is in your water to begin with

Whether RO is worth it for you depends on your starting point. On city water, your utility publishes a yearly water quality report that lists what was found and at what levels. On a private well, the EPA says the owner is responsible for the water, and advises testing every year with a certified laboratory. Neither a report nor a test tells you about your health, but both tell you what a system would be treating.

Hardness, taste and the word healthy

A lot of what people want from RO is about taste, scale and spots on glasses. Water utilities are careful to separate those from health. Water utilities say plainly that hard water is not a health hazard, and that there is no health-based drinking water standard for it. City water quality reports note that taste, odor and hardness are not regulated under drinking water health standards.

The EPA’s secondary standards work the same way: they are guidelines for taste, color and odor, such as 500 mg/L for total dissolved solids, and the EPA does not enforce them. Wanting better-tasting water is a perfectly good reason for an RO system. It is a taste reason, not a health one.

What about minerals, and the kidneys?

Questions like whether RO water is hard on the kidneys, or whether you miss out on minerals, are health questions. None of the public sources this site relies on answers them, and this site will not guess. Take them to your doctor, together with your water report or test.

Questions worth taking to a doctor

• Is there anything in my water report or well test I should be concerned about?
• Is there anything about my diet or health that affects which water treatment I choose?
• If I use a water softener as well, does the sodium it adds matter for me?

On that last point, water utilities note that in home softeners, sodium is added to the water in exchange for the hardness removed, and suggest that people on sodium-restricted diets consult their physician. See reverse osmosis vs a water softener.

Questions worth taking to an RO pro

• Which contaminants is this system certified to reduce, by name, and under which standard? NSF/ANSI 58 is the standard for reverse osmosis drinking water treatment systems.
• What do my water report or well test say this system would be treating?
• What upkeep keeps it working as certified?

To understand the machine, read how reverse osmosis works. To have one fitted, read RO system installation, or send the form and an independent local RO pro can contact you.

Questions people ask