3MRO401
A NSF-certified reverse osmosis filter that is certified to reduce 15 contaminants, including lead and fluoride.
You want the most thorough filtration — the only common type that removes fluoride, arsenic, and dissolved solids. Accept some water waste.
Certified to reduce Arsenic, Chromium-6, Fluoride — the contaminants that matter most for health.
Reverse osmosis wastes some water (a few gallons per gallon produced) and strips beneficial minerals along with contaminants — the trade-off for the most thorough filtration. Expect a storage tank and slower flow.
What is reverse osmosis system? A multi-stage under-sink system that forces water through a semi-permeable membrane, removing the widest range of contaminants — including dissolved ones carbon can’t touch. Compare all filter types →
What it costs to own
| Upfront price | — |
| Replacement filter (3MROP411 3MROP412 3MROM413 3MROP416) | $206.51 Buy refill → |
| Estimated yearly cost (filters, ~1×/yr) | ~$207/yr |
| True cost per gallon | 13.8¢ |
Cost per gallon and yearly cost are our estimates from the rated capacity and the Amazon price as of October 20, 2026 at 2:01 PM ET. We show them only when we read the price from Amazon in the last 24 hours. The filter only works if you replace it on schedule.
What it's certified to remove
Certification is per-contaminant: the 3MRO401 is credited only for the contaminants listed here, verified by NSF. It does not imply removal of anything not listed.
✓ Verify this certification on the official NSF listing →
Full specifications
| Certified by | NSF |
| NSF/ANSI standards | 42 — reduces taste, odor, and chlorine (aesthetic standard) · 58 — reverse osmosis — removes dissolved solids, fluoride, and arsenic |
| Filter type | Reverse osmosis system |
| Rated capacity | 1,500 gallons |
| Flow rate | .5 gpm |
| Replacement element | 3MROP411 3MROP412 3MROM413 3MROP416 |
| Installation | Under-sink system with a dedicated faucet and storage tank. |
Frequently asked
Is the 3MRO401 NSF certified?
Yes — the 3MRO401 is listed in the NSF certified-product database under NSF/ANSI standards 42, 58. That means an independent body verified its claims (not just "tested to" a standard).
Does the 3MRO401 remove arsenic?
Yes. It is certified to reduce Arsenic, Chromium-6, Fluoride, Lead, plus 11 other contaminants. Certification is per-contaminant, so it is only credited for what is on its listed claim set.
What does the 3MRO401 remove?
It is certified to reduce 15 contaminants: Arsenic, Barium, Cadmium, Chlorine / chloramine, Chromium, Chromium-6, Copper, Cryptosporidium, Fluoride, Giardia, and more.
How much does the 3MRO401 cost per gallon?
About 13.8¢ per gallon, based on its rated capacity of 1,500 gallons and the Amazon price on October 20, 2026 at 2:01 PM ET.
How often do you replace the reverse osmosis filter?
A reverse osmosis filter like this is typically replaced about 1 time a year (replacement element 3MROP411 3MROP412 3MROM413 3MROP416). Replace on schedule — a spent cartridge stops reducing contaminants.
Compare similar reverse osmosis filters
Source: NSF public certification listing. Specs and certified claims are from the official listing; cost figures are our estimates. Some links are affiliate links — see our disclosure.