NSF/ANSI 42, 53 and 401: Filtration Systems Standards

The most common certifications for filtration systems are NSF/ANSI 42, 53, and 401, which certify that a product effectively reduces specific contaminants from drinking water.

NSF/ANSI 42: Drinking Water Treatment Units – Aesthetic Effects

This standard establishes minimum requirements for systems designed to reduce non-health-related contaminants.

• Scope: Point-of-use and point-of-entry systems.
• Claims: Chlorine, taste and odor, chloramine, particulate, iron, manganese, zinc, and total dissolved solids (TDS).
• Testing: Material safety (including content in accordance with NSF/ANSI/CAN 372), structural integrity, and specific aesthetic-related contaminant reduction claims (claims vary by product).

NSF/ANSI 53: Drinking Water Treatment Units – Health Effects

This standard establishes minimum requirements for systems designed to reduce specific health-related contaminants.

• Scope: Point-of-use and point-of-entry systems.
• Claims: This standard offers over 50 contaminant reduction claims. Some of the most popular include lead, Cryptosporidium, VOCs, and chromium.
• Testing: Material safety (including content in accordance with NSF/ANSI/CAN 372), structural integrity, and specific health-related contaminant reduction claims (claims vary by product).

NSF/ANSI 401: Emerging Compounds/Incidental Contaminants

This standard addresses the ability of a water treatment device to remove up to 15 individual contaminants identified in published studies as occurring in drinking water. The pollutants covered in NSF/ANSI 401 have been detected in drinking water supplies at trace levels and can affect some consumers’ perception of drinking water quality.

• Scope: Point-of-use and point-of-entry systems.
• Claims: This standard offers up to 15 specific contaminant reduction claims. The most popular categories include prescription drugs, over-the-counter medications, herbicides, pesticides, and chemical compounds.
• Testing: Material safety (including content in accordance with NSF/ANSI/CAN 372), structural integrity, and specific emerging compounds/incidental contaminants outlined in the standard.