NSF 58: what our membrane certification really guarantees
More and more of you are asking us detailed questions about the NSF certification of our reverse osmosis systems. That's a good thing: a device that treats the water you drink every day deserves to be checked. So here, without jargon or exaggeration, is what our certification covers, what it doesn't, and how to verify it yourself.
What is NSF?
NSF is an independent organisation founded in the United States in 1944. Together with the American National Standards Institute (ANSI), it writes the reference standards for drinking water treatment devices. It also tests products and audits the factories that make them. Its mark is one of the most widely recognised in the field.
NSF/ANSI 58 in brief
NSF/ANSI 58 is the standard dedicated to residential reverse osmosis systems. It has three parts:
- Material safety: parts in contact with water must not release anything harmful into it.
- Structural integrity: the device must withstand mains water pressure without leaking or bursting.
- Performance: claimed reduction rates (dissolved solids, nitrates, lead, etc.) must be measured in a laboratory.
A certification can apply to a complete system or to a single component, and to all or only some of these parts. That's why you should always check what is certified, and for what.
What our certification covers
The reverse osmosis membrane in our systems is on the official NSF/ANSI 58 listing, under the name of its manufacturer, Ningbo RXHL Technology. In practice:
- The materials were tested by NSF in its laboratory in Ann Arbor (USA). Water that had passed through the membrane was analysed for more than 150 substances: solvents, phthalates, nitrosamines, aromatic hydrocarbons, antimony. None exceeded the safety thresholds.
- The membrane meets the “lead-free” requirements of US law (less than 0.25% lead as a weighted average).
- An initial flush is required: the certification specifies that a new membrane must be flushed. Our installation manual includes this step.
- The factory is monitored by NSF, which checks that the membranes produced remain identical to the model tested.
What it doesn't cover
We prefer to be clear. Our certification covers the membrane's materials. It does not certify:
- the complete system (housing, cartridges, fittings);
- contaminant reduction rates.
Reverse osmosis is recognised as one of the most effective home technologies against dissolved salts, nitrates, heavy metals and PFAS. But if we state a precise figure for our devices, it has to come from a test on our devices.
What about NSF 61?
It's one of the questions we're asked most often. NSF/ANSI 61 does not apply to under-sink reverse osmosis systems. It covers components of the drinking water network: pipes, valves, meters, and equipment installed where water enters a building.
According to NSF, products certified to NSF 58 do not need to be certified to NSF 61. Their materials are evaluated with a method suited to household devices, but against the same toxicity thresholds, those of NSF/ANSI 600. NSF considers this approach “equally protective”. An under-sink system presented as “NSF 61 certified” therefore usually reflects confusion between the two standards.
How to check it yourself
- Go to NSF's official database of drinking water treatment units.
- Search for the manufacturer: Ningbo RXHL Technology.
- Check that our membrane reference, [RHD3013-600], appears on the NSF/ANSI 58 listing.
A PDF certificate can be edited; the online listing cannot. The listing is what counts, for us as for any brand.
What about Europe?
NSF certification is not mandatory in Europe, but it remains a recognised benchmark. The European Union is putting its own framework in place: from 1 January 2027, materials in contact with drinking water will have to meet harmonised rules (Directive 2020/2184). We are following this closely with an independent laboratory to ensure our range complies.
Our commitments
- Only cite certifications that can be verified, with a link to their source.
- Publish our test results as soon as they are available.
- Answer your technical questions, even the most detailed ones: https://www.aquacycle.be/pages/contact
Quality water starts with quality information. If you have a question this article doesn't answer, write to us.
Sources
- NSF – What NSF Standards Reference NSF/ANSI/CAN 61
- ANSI – NSF/ANSI 58-2022, Reverse Osmosis for Drinking Water
- TZW – Materials in contact with drinking water: EU regulations
- Official NSF listing of 8 August 2024 and NSF evaluation report of 11 June 2024 (Ningbo RXHL Technology, RHD3013-600), provided by Aquacycle
- aquacycle.be: pages consulted on 21 October 2026
