Certifications & Standards (NSF/ANSI)
NSF/ANSI 42/53/401/58 and how to verify claims.
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NSF/ANSI 44 Water Softeners: What the Claim Means
An NSF/ANSI 44 claim indicates that a residential cation-exchange water softener was evaluated to applicable requirements of that…
NSF Standards vs. Protocols: What Filter Claims Mean
NSF/ANSI standards and NSF protocols are different types of requirements documents, not two grades of product safety. A…
NSF 372 vs. Lead Reduction Certification: Key Differences
Compare NSF/ANSI/CAN 372 and lead reduction certification to see which claim addresses lead content and which verifies lead…
NSF/ANSI 55 Class A vs Class B UV Water Systems
Compare NSF/ANSI 55 Class A and Class B UV systems to choose the right option based on water…
Water Filter Capacity Claims: 3 Ways to Know Your Limit
Most filters are rated by gallons or months—not your tap water. Match the rating to your household demand,…
NSF/ANSI 244 Microbial Filters: 5 Limits to Know
NSF/ANSI 244 addresses microbial reduction—not every water risk. Compare flow, maintenance, and household fit for your home, so…
Prop 65 Warnings on Water Filters: 5 Things to Know
See what Prop 65 warnings on water filters really mean, how they compare with certifications, and which questions…
NSF ANSI 53 vs 401 vs 58: Pick the Right Filter
3 standards, 3 filter paths: match NSF/ANSI 53, 401, or 58 to lead, PFAS, VOCs, or RO needs…
WQA Gold Seal vs NSF Certification: 5 Key Differences
5 key differences between WQA Gold Seal and NSF certification show what each mark means and help you…
Choosing a Chloramine Filter: Standards, Media, and Practical Setup Choices
Learn how to choose a chloramine filter, which standards and filter media matter, and how to match systems…
Choosing a PFAS Water Filter: How to Read the Label Carefully
Learn how to read water filter labels for PFAS reduction, from certifications to micron ratings, so you can…
Choosing a Lead-Removal Water Filter: Which Certification Standard Matters Most
Learn which NSF/ANSI standards to look for when choosing a water filter for lead, how they differ, and…
Certified Claims vs “Tested To”: How to Read Water Filter Marketing Language
Learn the difference between certified claims and “tested to” wording on water filters so you can compare products,…
How to Verify a Water Filter’s Certification Claim Step-by-Step
Learn step-by-step how to verify home water filter certification claims, read NSF-style labels correctly, and confirm what contaminants…
NSF/ANSI 401 Explained: Emerging Contaminants in Plain English
Learn what NSF/ANSI 401 means, which emerging contaminants it covers, how it compares to NSF 42, 53, and…
NSF/ANSI 42 vs 53: Which One Matters for You?
Understand the difference between NSF/ANSI 42 and 53 water filter standards, what each covers, and how to decide…