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FilterScored

Water · Best-of

Best Under-Sink Water Filter

Bottom line

The best under-sink filter combines broad NSF/ANSI 42, 53, and 401 certification with a low cost per gallon - the Culligan US-EZ-4 and Epic Smart Shield lead our certified set.

If you want broad coverage without anything sitting on the counter, an under-sink carbon filter is the sweet spot for most homes: it holds a lot of water before the cartridge tires out, keeps good flow, hides under the sink, and often carries wide certification. We rank these by what they're actually certified to remove and what they cost to run.

How we score: We rank under-sink filters by overall score, which weighs certified reduction, cost per gallon, and how much water the cartridge handles before it needs replacing.

  1. 17.5
    Culligan US-EZ-4 Under-Sink

    The Culligan US-EZ-4 Under-Sink is a under sink water filter. It is third-party certified (IAPMO) to reduce chlorine taste and odor, chloramine, lead, mercury, cysts, VOCs, MTBE, turbidity, PFOA, PFOS. It is also marketed for pharmaceuticals, for which we found no accredited third-party certification (so we award no certification credit; this is not a finding that it fails to reduce them). Running cost works out to about $0.091 per gallon.

    • Certified to reduce: chlorine taste and odor, chloramine, lead, mercury, cysts, VOCs, MTBE, turbidity, PFOA, PFOS
    • Cartridge life: 500 gallons
    • Cost per gallon: $0.091
  2. 27.2
    Aquasana AQ-5200 Under-Sink

    The Aquasana AQ-5200 Under-Sink is a under sink water filter. It is third-party certified (WQA) to reduce lead, chlorine taste and odor, chloramine, PFOA, PFOS, VOCs, mercury, asbestos, cysts, MTBE, microplastics, pharmaceuticals. Running cost works out to about $0.148 per gallon.

    • Certified to reduce: lead, chlorine taste and odor, chloramine, PFOA, PFOS, VOCs, mercury, asbestos, cysts, MTBE, microplastics, pharmaceuticals
    • Cartridge life: 500 gallons
    • Cost per gallon: $0.148
  3. 36.8
    Frizzlife SK99 Under-Sink Filter

    The Frizzlife SK99 Under-Sink Filter is a under sink water filter. It is third-party certified (IAPMO) to reduce chlorine taste and odor, lead, VOCs, sediment, cysts. It is also marketed for chloramine, mercury, cadmium, fluoride, PFOA, PFOS, for which we found no accredited third-party certification (so we award no certification credit; this is not a finding that it fails to reduce them). Running cost works out to about $0.031 per gallon.

    • Certified to reduce: chlorine taste and odor, lead, VOCs, sediment, cysts
    • Cartridge life: 1,600 gallons
    • Cost per gallon: $0.031
  4. 45.7
    Waterdrop 10UA Under-Sink

    The Waterdrop 10UA Under-Sink is a under sink water filter. It is third-party certified (IAPMO) to reduce chlorine taste and odor. It is also marketed for PFAS, PFOA, PFOS, lead, sediment, for which we found no accredited third-party certification (so we award no certification credit; this is not a finding that it fails to reduce them). Running cost works out to about $0.005 per gallon.

    • Certified to reduce: chlorine taste and odor
    • Cartridge life: 8,000 gallons
    • Cost per gallon: $0.005
  5. 54.1
    Epic Smart Shield Under-Sink

    The Epic Smart Shield Under-Sink is a under sink water filter. It is third-party certified (IAPMO) to reduce chlorine taste and odor, lead, VOCs, chloramine, mercury, cysts, pharmaceuticals. It is also marketed for PFAS, PFOA, PFOS, microplastics, for which we found no accredited third-party certification (so we award no certification credit; this is not a finding that it fails to reduce them). Running cost works out to about $0.177 per gallon.

    • Certified to reduce: chlorine taste and odor, lead, VOCs, chloramine, mercury, cysts, pharmaceuticals
    • Cartridge life: 651 gallons
    • Cost per gallon: $0.177
  6. 61.7
    Clearly Filtered 3-Stage Under-Sink

    The Clearly Filtered 3-Stage Under-Sink is a under sink water filter. It carries no accredited NSF, WQA, or IAPMO certification - its contaminant claims are "tested to" lab results, not certifications. It is also marketed for chlorine taste and odor, fluoride, lead, PFAS, PFOA, PFOS, arsenic, mercury, chromium, pesticides, pharmaceuticals, VOCs, chloramine, for which we found no accredited third-party certification (so we award no certification credit; this is not a finding that it fails to reduce them). Running cost works out to about $0.198 per gallon.

    • Certified to reduce: nothing certified (claims are 'tested to' only)
    • Cartridge life: 2,000 gallons
    • Cost per gallon: $0.198

FAQ

Are under-sink filters hard to install?
Usually not. Most direct-connect models are tool-free or a simple DIY job. The exception is a system with its own dedicated faucet, which needs a hole drilled in the sink or counter - so if you're renting or wary of drilling, check the install type, which we note on each scorecard.

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