Certified under-sink RO review
Aquasana SmartFlow Review
The broadest certification of any under-sink RO in this guide: WQA tested to five NSF/ANSI standards and CSA B483.1 for 90 named contaminants, with remineralization after filtration. It is the certified step up from the APEC, at a higher but still reasonable price.
Aquasana SmartFlow
WQA NSF/ANSI 42, 53 (P473), 58, 401, CSA B483.1 · 90 contaminants · remineralization
Check price on Amazon →What the SmartFlow actually is
The SmartFlow is a tank-based under-sink reverse-osmosis system with a patented design that reduces wastewater and adds beneficial minerals back into the water after filtration. It is WQA tested and certified to NSF/ANSI 42, 53 (including P473 for PFAS), 58, 401, and CSA B483.1, covering 90 named contaminants including fluoride, lead, arsenic, and chlorine.
The remineralization stage is the differentiator. Most RO systems strip water of calcium and magnesium; the SmartFlow adds them back, which improves taste and addresses the “flat” texture some people dislike about demineralised water.
Specifications that matter
| Spec | Detail |
|---|---|
| Type | Under-sink RO with tank and remineralization |
| Certification | WQA to NSF/ANSI 42, 53 (P473), 58, 401, CSA B483.1 |
| Contaminants | 90 named, including PFAS, fluoride, lead, arsenic |
| Remineralization | Yes |
| Upfront price | ~$225–$240 |
| Smart features | None (filter changes on schedule) |
What we liked
The certification list is the strongest under-sink in this guide. NSF/ANSI 401 covers emerging contaminants including pharmaceuticals and some PFAS, and the P473 listing specifically covers PFOA/PFOS. That is a level of third-party verification the APEC does not carry.
Remineralization makes the water taste better. If you dislike the flat taste of RO water, this addresses it without a separate cartridge.
The price is reasonable for the certification. At around $225–$240, it costs only $25–$40 more than the APEC while carrying a much broader certification list.
What we did not like
Proprietary filters cost more than standard 10-inch cartridges. The APEC’s running cost is lower because it uses generic filters. The SmartFlow’s filters are proprietary and more expensive per year.
No smart features. Like the APEC, there is no filter-life indicator or app. You track replacement on a calendar.
Installation is still under-sink plumbing. If you rent or cannot modify plumbing, this is not an option. The AquaTru Classic offers similar certification in a countertop form factor.
SmartFlow vs AquaTru Classic
| Aquasana SmartFlow | AquaTru Classic | |
|---|---|---|
| Form factor | Under-sink | Countertop |
| Certification | 5 standards + CSA, 90 contaminants | 5 standards, 84 contaminants |
| Remineralization | Yes | No |
| Upfront price | ~$225–$240 | ~$475 |
| Installation | Plumbing required | None |
The SmartFlow is cheaper and remineralizes, but requires installation. The AquaTru Classic is more expensive and has no remineralization, but plugs in with zero plumbing. The right choice depends on whether you can install under-sink.
Who should buy it
Buy the SmartFlow if: you own your home, you want the broadest under-sink certification available, and you prefer water with minerals added back.
Skip it if: you rent, you want smart filter tracking, or you need the absolute lowest running cost.
Verdict
The certified under-sink RO for people who want proof and better taste. More expensive than the APEC upfront and in filters, but the five-standard certification and remineralization justify the difference for many buyers.
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