---
title: "NSF certification — what it means"
description: "Tested and certified by NSF against a public health or food equipment standard. What the symbol looks like, what happens if you ignore it, and where its meaning diff"
url: https://atoneplace.net/symbol/cert-nsf/
site: "At One Place"
---

# NSF certification

**NSF certification: Tested and certified by NSF against a public health or food equipment standard.**

## What it looks like

The letters NSF inside a blue circle or oval.

## What it means

Most often met on water filters, commercial catering equipment and dietary supplements. The standard number printed with it is what the mark actually claims: NSF/ANSI 42 covers aesthetic reduction such as chlorine taste, while 53 covers health-related contaminants including lead and cysts, and a filter certified to 42 alone makes no health claim at all. On catering equipment it certifies that surfaces and joints can be cleaned to a sanitary standard.

> Defined by NSF/ANSI standards. Where a symbol differs between standards, the difference is described above rather than resolved — both versions are in circulation on real labels.

## Other certification marks symbols

| Symbol | Means |
| --- | --- |
| Energy Star | The product meets US Environmental Protection Agency efficiency criteria for its category. |
| Fairtrade Mark | The certified ingredients were bought on Fairtrade terms, including a minimum price and a premium paid to the producer organisation. |
| OEKO-TEX Standard 100 | Every component of the textile was tested for harmful substances and passed. |
| Woolmark | The product is made from pure new wool and meets the Woolmark performance specifications. |
| BSI Kitemark | BSI has tested the product and audits the factory that makes it. |
| GS mark (Geprüfte Sicherheit) | Tested safety — a German voluntary mark requiring independent testing and factory surveillance. |
| Kosher certification (OU and others) | A certifying agency attests that the product is kosher, often with a letter alongside for the category. |
| Halal certification | A certifying body attests that the product complies with Islamic dietary rules. |
| USDA Organic seal | At least 95% of the ingredients are certified organic under the US National Organic Program. |
| EU organic leaf | At least 95% of the agricultural ingredients are organic under EU rules. |
| Crossed grain (certified gluten free) | Independently certified to contain no more than 20 parts per million of gluten. |
| Vegan Society sunflower | Registered with the Vegan Society: no animal ingredients and no animal testing at any stage. |
| Leaping Bunny | Certified cruelty free: no animal testing by the company, its suppliers or third parties after a fixed cut-off date. |

## Common questions

### What does the nsf certification symbol mean?

Tested and certified by NSF against a public health or food equipment standard.

### What does it look like?

The letters NSF inside a blue circle or oval.

## Related pages

- [BSI Kitemark](https://atoneplace.net/symbol/cert-kitemark/)
- [Food safe (glass and fork)](https://atoneplace.net/symbol/food-glass-and-fork/)
- [Energy Star](https://atoneplace.net/symbol/cert-energy-star/)
- [Fairtrade Mark](https://atoneplace.net/symbol/cert-fairtrade/)
- [OEKO-TEX Standard 100](https://atoneplace.net/symbol/cert-oeko-tex/)
- [Woolmark](https://atoneplace.net/symbol/cert-woolmark/)
- [BSI Kitemark](https://atoneplace.net/symbol/cert-kitemark/)
- [GS mark (Geprüfte Sicherheit)](https://atoneplace.net/symbol/cert-gs/)
- [Kosher certification (OU and others)](https://atoneplace.net/symbol/cert-kosher-ou/)
- [Halal certification](https://atoneplace.net/symbol/cert-halal/)
- [USDA Organic seal](https://atoneplace.net/symbol/cert-usda-organic/)
- [EU organic leaf](https://atoneplace.net/symbol/cert-eu-organic/)

## Sources

- Official vendor product documentation — At One Place (/about/)