What does an ANSI Certification mean for water purification?

The American National Standards Institute (ANSI), a non-profit group

Although non-governmental, the National Science Foundation (NSF) does have some official status as the lead agency for testing and approving the chemicals used in water treatment plants and the materials of construction used in drinking water systems.

The ANSI/NSF certification is considered the best in the industry, so having this certification ensures that the water filter you’re buying meets the highest standards.