NSF (National Sanitary Foundation) is the World Health Organization (WHO) food and water safety cooperation center, one of three prestigious independent, non-governmental, non-profit inspection organizations (alongside WQA – Water Quality Association, UL – Underwriters Laboratories).

NSF certification ensures that the product has safe quality as advertised by the manufacturer. NSF only certifies a product when it meets five requirements:

Filtration capacity as committed by the manufacturer.
The filter does not add toxic substances to the water
The filter has a sustainable structure.
Advertisements, technical documents and labels are not misleading.

Materials and processes remain unchanged, meaning the product has consistent quality and reliability

There are currently six NSF standards for the use and performance of drinking water treatment units:

Standard 42: Sensory Standards for Drinking Water Treatment Units (Taste, Odor, Color)
Standard 44: Cation Exchange Water Softeners
Standard 53: Health and Safety Standards for Drinking Water Treatment Units
Standard 55: Ultraviolet Water Treatment Systems
Standard 58: Advanced Health and Safety Standards for Reverse Osmosis Drinking Water Systems
Standard 62: Drinking Water Distillation Systems