A competitive filter market requires manufacturers to validate the performance and safety of their products.  UL’s filter testing and certification program demonstrates that products perform as expected, are safe for use as instructed, and meet industry standards. Certifications to filter standards for drinking water are required by many retailers, and in some cases, by model plumbing codes or state regulations.

  • NSF/ANSI 42 evaluates filters making aesthetic reduction claims (chlorine, particulate, etc.)
  • NSF/ANSI 53 evaluates filters making health related reduction claims (lead, arsenic, cysts, )
  • NSF/ANSI 61 evaluates point-of-entry and municipal filtration products for safety of materials that contact drinking water
  • NSF P231 evaluates microbiological water purifiers based on the recommendations of the EPA’s Guide Standard and Protocol for Testing Microbiological Water Purifiers (1987)


  • Safety of Materials: Water contact materials are evaluated to ensure they do not leach harmful contaminants into water.
  • Structural Integrity: Plumbed-in products are evaluated to ensure their parts don’t crack or burst under pressure.
  • Performance: Products are tested to ensure they can reduce claimed contaminants..
  • Product Literature: Manuals, performance datasheets, packaging, and data plates are evaluated to make sure product claims match test data and include relevant information.
  • Continued Compliance: Annual inspections of your products confirm continued compliance with the standards.