A.O. Smith High Efficiency Reverse Osmosis AOS-HERO-CHR
A WQA-certified reverse osmosis filter that is certified to reduce 1 contaminant at about 40.0¢ per gallon.
As an Amazon Associate we earn from qualifying purchases — disclosure. Price as of August 20, 2026; check Amazon for the current price.
You want the most thorough filtration — the only common type that removes fluoride, arsenic, and dissolved solids. Accept some water waste.
Certified to reduce 1 contaminants.
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 | $99.99 |
| Replacement filter (AOS-HERO-S1S3) | $99.99Buy refill → |
| Estimated yearly cost (filters, ~1×/yr) | ~$100/yr |
| True cost per gallon | 40.0¢ |
Cost per gallon and yearly cost are our estimates from the rated capacity and current prices. The filter only works if you replace it on schedule.
What it's certified to remove
Certification is per-contaminant: the A.O. Smith High Efficiency Reverse Osmosis AOS-HERO-CHR is credited only for the contaminants listed here, verified by WQA. It does not imply removal of anything not listed.
✓ Verify this certification on the official WQA listing →
Full specifications
| Certified by | WQA |
| NSF/ANSI standards | 42 — reduces taste, odor, and chlorine (aesthetic standard) · 53 — certified for health contaminants such as lead, VOCs, and cysts · 58 — reverse osmosis — removes dissolved solids, fluoride, and arsenic · 401 — reduces emerging contaminants such as pharmaceuticals and pesticides |
| Filter type | Reverse osmosis system |
| Rated capacity | 250 gallons |
| Flow rate | 0.7 gpm |
| Replacement element | AOS-HERO-S1S3 |
| Installation | Under-sink system with a dedicated faucet and storage tank. |
Frequently asked
Is the A.O. Smith High Efficiency Reverse Osmosis AOS-HERO-CHR NSF certified?
Yes — the A.O. Smith High Efficiency Reverse Osmosis AOS-HERO-CHR is listed in the WQA certified-product database under NSF/ANSI standards 42, 53, 58, 401. That means an independent body verified its claims (not just "tested to" a standard).
What does the A.O. Smith High Efficiency Reverse Osmosis AOS-HERO-CHR remove?
It is certified to reduce 1 contaminants: Total dissolved solids.
How much does the A.O. Smith High Efficiency Reverse Osmosis AOS-HERO-CHR cost per gallon?
About 40.0¢ per gallon, based on its rated capacity of 250 gallons and current price.
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 AOS-HERO-S1S3). Replace on schedule — a spent cartridge stops reducing contaminants.
Compare similar reverse osmosis filters
Source: WQA 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.