What is reverse osmosis, and how does it work?
Water pushed through a membrane so fine almost everything else stays behind.
Reverse osmosis pushes water through a membrane with pores so small that most dissolved solids, metals and chemicals get left behind. Here's how it works, step by step.
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- You heard RO is the best filter and want to know why
- You're wondering if RO water is healthy
Here's how it works, simply.
How it works, step by step
- Sediment pre-filter catches grit
- Carbon pre-filter removes chlorine, which protects the membrane
- RO membrane separates clean water from dissolved stuff
- Concentrate flushes to the drain
- Post-filter and remineralization polish the taste
What it removes, and what it doesn't
Certified RO reduces lead, fluoride, arsenic, nitrates, PFOA and PFOS, and most dissolved solids. Don't rely on it for bacteria; add UV for that.
RO vs distilled
Distilled water is boiled and condensed. RO is pushed through a membrane. Both are very low in dissolved solids, but RO is made right at your sink.
Our take
Why the carbon stage matters more than people think
This is the stuff our customers ask us most, after 20+ years and [thousands] of systems sold.
RO membranes are damaged by chlorine. That's why every good RO system has a carbon pre-filter in front. If you skip changing the pre-filter, chlorine reaches the membrane and it wears out early.
In chloramine cities, that pre-filter has to handle chloramine too. That's one more reason to change filters on schedule, and why we put them on a subscription.
Written by people who install these every day
20+ years in water. No fluff, just how it really works.
- 20+ years in water
- Our own patents
- We supply other water companies
- [Thousands] of systems sold
- Licensed installers
Written by [Name], [title], [20+] years in water treatment. Reviewed by [Licensed plumber name], license # [#]. Last updated [date]. Sources: listed under each "By the numbers" block and linked in the copy
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Questions people ask
What is reverse osmosis water?
Water pushed through a fine membrane that removes most dissolved solids.
Is reverse osmosis water good for you?
Yes. Most minerals come from food; remineralization adds some back.
Does reverse osmosis remove minerals?
Yes, which is why we remineralize.
Does reverse osmosis remove fluoride?
Yes.
Is RO the same as distilled water?
No, different process, similar purity.
Does reverse osmosis waste water?
Some. Newer tankless systems waste much less.