Water & Wellness · Water education
Understanding Water Filter Certifications
Read the reduction claim and the model together. A standard number is not a score for how much a filter removes.
| Standard | What to look for |
|---|---|
| NSF/ANSI 42 | Aesthetic claims, such as chlorine, taste and odor. Check the specific listed claims. |
| NSF/ANSI 53 | Specified contaminants with health effects. Certification does not include every contaminant covered by the standard. |
| NSF/ANSI 58 | RO systems. Review the model’s individual reduction claims. |
| NSF/ANSI/CAN 61 | Health-effects requirements for materials in contact with drinking water. |
| NSF/ANSI/CAN 372 | Lead content in the product’s materials, not removal of lead from the water. |
Four things to check before comparing filters
- Exact model: the system and cartridge configuration must match.
- Named substance: look for the contaminant you want reduced.
- Rated conditions: consider flow, capacity, and the test’s stated limitations.
- Evidence type: distinguish a certification listing from a laboratory report or a general media description.
How we present Purative’s documentation
Our Purative performance section identifies the documented underlying-system claims and the current status of the branded configuration. We provide applicable certificates on request so you can ask about the system you are actually considering.
When comparing products, ask: “Can you show me the evidence for this claim on this exact system?” That question is more useful than counting logos.