About FilterFacts

Last updated: September 17, 2026

FilterFacts is an independent review site with one editorial principle: judge water filters by their certification records, not their marketing.

Every water filter worth buying makes claims about what it removes. The claims that matter are the ones an accredited third party tested and listed publicly — NSF, the Water Quality Association (WQA), and IAPMO R&T all maintain public databases of certified products and their exact certified claims. We start every review there.

Our methodology

1. Pull the certification record. For each system, we look up the exact model number in the public NSF, WQA, and IAPMO listings and record which standards it's certified to (42, 53, 58, 401, 372) and which specific contaminant claims are listed.
2. Separate "certified" from "tested." "Certified to" means an accredited body lists the product. "Tested to" means a lab ran the protocol. Both can be legitimate; we always say which one a product is.
3. Compare certified claims side by side. Contaminant-reduction tables on this site reflect listed, checkable claims — never marketing copy repeated as fact.
4. Run the 10-year cost math. Purchase price + replacement filters + installation, converted to cost per gallon. The sticker price is never the whole story.
5. Publish limitations. If a certification is narrower than the marketing suggests, we say so. Rankings reflect this record — commissions never buy placement (disclosure).

What we don't do

• We don't repeat manufacturer health claims. A filter certified to reduce lead is described as exactly that — never as something that "protects your family from illness."
• We don't invent test results, prices, or certification claims. Where a record is worth checking yourself, we tell you how (the guide).
• We don't review products we can't verify against a certification listing or a manufacturer's published performance data sheet.

Who writes this

FilterFacts is produced by a small editorial team that researches water treatment certifications full-time. We publish as an editorial team rather than under individual bylines, and every page reflects the methodology above — not personal endorsements. If you spot an error in a certification record we've cited, tell us and we'll correct it.

How we make money

Reader-supported: we earn commissions from affiliate links to Aquasana and Epic Water Filters when readers buy through them. Read the full disclosure.