Editorial policy

How a product is assessed

• Certified performance first: NSF/ANSI 42, 53, 58, 401 and P473 claims are checked against the certifying body, not the marketing page.
• Contaminant coverage is compared class by class — lead, PFAS, chlorine and disinfection by-products, VOCs, microbiological, fluoride.
• Running cost is calculated per litre over the filter's rated life, not by cartridge sticker price.
• Flow rate, capacity, installation burden and replacement cadence are weighted for real household use.

Scoring

Ratings reflect verified performance against price. A product with strong certification and honest running costs will outrank a better-marketed rival every time. No score is adjusted after the fact for commercial reasons.

Independence

Manufacturers do not see articles before publication, cannot approve or veto content, and cannot buy placement. Commercial links are added only after the verdict is written. See our affiliate disclosure.

Corrections

If we get something wrong we fix it in place and note the change. Report an error through the contact page and include the page and the source that contradicts us.

Authors

Every article carries a named editor from our editorial team, assigned by subject area.