Evidence and transparency · Sources checked on 23 September 2026
You are considering a water filter, but first you want to know what it has actually been shown to do. That is a fair question. A certification mark, laboratory report or impressive percentage only becomes meaningful when you know which model, which substance and which test conditions it refers to.
In short: an independent test or official certification can provide valuable evidence, but it does not automatically cover every version of a product or every substance. Below we explain what evidence we can identify for each product family and which links to our exact products we are still checking.
Putting the drinking-water news in context
According to the Dutch regulator, supplied drinking water meets the legal PFAS standards. Recent news also discusses a stricter health-based guideline, which is not the same as the legal limit. A result for a postcode area is not a measurement at your own tap. See the explanations from the Dutch National Institute for Public Health and the Environment (RIVM) and the Human Environment and Transport Inspectorate (ILT).
If you want to reduce certain substances further, you can choose a suitable water filter. The honest question is: what has actually been demonstrated for that specific system?
Test, certificate and mark: what is the difference?
Official product certification
A certification body assesses a named model against a standard. The official product listing shows which standard and specific reduction claims apply to that model. NSF/ANSI 58 concerns reverse-osmosis systems; the standard number alone does not mean that PFAS reduction is certified for every model. Check the exact substance claim in the listing.
Independent laboratory testing
A laboratory report describes the measured performance of a tested sample under stated conditions. This is useful evidence, but it is not the same as ongoing product certification. Check the substance tested, water quality, flow rate, filter age and whether the tested sample matches the product you buy.
Certification of a component
A membrane or filter material may have its own certification without the complete tap or system being certified. CE or FCC marking is not, by itself, evidence of PFAS reduction either.
NSF's guidance can help you check a filter claim and its official listing.
Four questions to ask about any water filter
- Which model? Does the model code in the evidence match the version that will be supplied?
- Which substance? A test for PFOA or PFOS is not evidence for every PFAS, nor automatically for TFA.
- What kind of evidence? Is it an official listing, an independent report, evidence for a component or a manufacturer's statement?
- What service life? A result obtained with a new filter does not automatically demonstrate performance at the end of its service life.
How to check a certification yourself
First ask for the exact model codes of the system and filters. Then search the official register of the organisation that issued the certificate, such as IAPMO R&T, NSF or WQA. Compare the model code, current status, standard and stated substance or performance claim. A standard number or logo without a matching product listing is not enough.
For PFAS, check whether the specific PFAS reduction claim appears for your model. Certification for TDS reduction, for example, is not automatically certification for PFAS reduction. The US Environmental Protection Agency (EPA) explains how to check the listing and PFAS claim. Dutch drinking-water standards and guidance from RIVM and ILT remain the relevant context in the Netherlands.
What evidence can we show for PureAqua solutions?
PureAqua uses its own product names. Source documents may instead use a manufacturer's or component's name. We therefore distinguish between available manufacturer evidence and confirmed evidence for the exact PureAqua version sold.
The Source, used with purified-water taps
Manufacturer model WOW50-20-209-001 has a current IAPMO R&T listing under NSF/ANSI 58. The reduction claim shown in that listing is TDS reduction, not PFAS reduction. We are still checking the link between this listing and the exact Source version sold by PureAqua, including the leak-detection version and replacement filters. We therefore do not present this listing as a certificate for every Source system.
PureFilter Mineral+, the standalone filter
An independent laboratory report has been published for the related Tappwater InlinePro SMR. It contains results for five individual PFAS compounds under the test conditions described in the report. The exact match with the version sold by PureFilter and any official product certification have not yet been confirmed. Testing according to an NSF method is therefore not automatically described as “NSF certified”.
Countertop water purification appliance
Tappwater publishes a summary of laboratory tests for the Countertop RO SMR, including results for specific PFAS compounds. The summary is not an official NSF listing for the complete PureAqua appliance. We are still matching the tested version and filter revision to the Countertop supplied by PureAqua.
PureAqua 4-in-1 with purified and boiling water
Supplier Tapure describes independent SGS tests for the RO3500 purification unit and separate certifications for certain components. The tests include PFOA and PFOS results with a new filter. This does not automatically mean that the complete 4-in-1 system is NSF certified. We are checking the exact components and revisions of each PureAqua version before attributing a test result to it.
What about TFA?
TFA is a specific substance receiving attention in recent drinking-water news. A result for PFOA, PFOS or other PFAS does not establish that the same filter also reduces TFA. At present, we do not have model-specific TFA reduction evidence for the exact versions sold by PureAqua that we can use as a customer claim. We therefore make no such promise.
The right filters and proper maintenance matter
A test result relates to a particular configuration and use case. The correct replacement filters, proper installation and replacement according to the instructions for your system are important. Do not order a filter based only on a general product name if you are unsure of your system version or generation.
Frequently asked questions
Does NSF/ANSI 58 mean all PFAS are removed?
No. Check whether a separate PFAS reduction claim is listed for the exact model. The standard number alone does not establish that.
Is a laboratory test the same as product certification?
No. A laboratory test describes the performance of a particular sample under particular conditions. An official product certification has its own model scope, standard and listed claims.
Does a PFAS test tell you anything about TFA?
Only if TFA was actually tested and the result applies to the correct system. A test for other PFAS should not be treated as evidence for TFA.
How can I request evidence for my system?
Tell us which PureAqua solution you have or are considering and, if you know it, the model number. We will explain what documentation is available and where its limits are.
