Water filter guides

Last reviewed July 2026.

Every brand we track, plus the standards explainers. The certification pages check whether a brand's claim is in a public listing and which standards it covers; the ranking pages put a dollar figure on each certified gallon.

Cost per certified gallon

• Water filter pitchers — ranked by cost per certified gallon
• Refrigerator water filters — ranked by cost per certified gallon

Is it actually certified? brand by brand

• Is Berkey NSF certified?
• Is Brita NSF certified?
• Is Clearly Filtered NSF certified?
• Is Epic Water Filters NSF certified?
• Is Everydrop Whirlpool NSF certified?
• Is LG NSF certified?
• Is PUR NSF certified?
• Is Samsung NSF certified?
• Is Waterdrop NSF certified?
• Is Zerowater NSF certified?

Standards & background

• NSF/ANSI 42 vs 53 vs 401: which one actually removes lead?
• Fake refrigerator water filters: how to spot one
• What "NSF certified" actually means (and doesn't)

We do not test filters — we index what accredited certifiers publish, with attribution, and make no health or treatment claims. A certification covers a specific model against a specific standard; it is not a general seal of quality. We are not affiliated with NSF International.