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Head-to-head · Best Under-Sink Water Filters

Aquasana Claryum AQ-5300+ vs Waterdrop G3P800 Tankless Reverse Osmosis System

Which is the better buy? Side-by-side on rating, price, strengths, and watch-outs — with the published ratings we averaged to get there.

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The short answer

Waterdrop G3P800 Tankless Reverse Osmosis System comes out ahead by a clear margin (4.5 vs 3.9). Waterdrop G3P800 Tankless Reverse Osmosis System is best for: city-water households that want fast, thoroughly purified drinking water on tap. Read the strengths below before deciding.

Aquasana Claryum AQ-5300+
Ranked #4 in Best Under-Sink Water Filters
Aquasana Claryum AQ-5300+
1 sourceall derived$199.99as of Sep 28

The Aquasana Claryum AQ-5300+ is the best all-around under-sink carbon filter, pairing NSF/ANSI 42, 53 and 401 certification with a fast-flow three-stage design that keeps healthy minerals in the water. It reduces 99% of 77 contaminants, including lead, chlorine, PFAS and pharmaceuticals, without the water waste of reverse osmosis. The trade-off is a 6-month filter life and a higher per-gallon cost. For clean, great-tasting water, it's a leading pick.

Strengths
  • — Triple-stage Claryum filtration reduces 99% of 77 contaminants including lead, chlorine, PFAS and pharmaceuticals
  • — NSF/ANSI 42, 53 and 401 certified, covering taste, health contaminants and emerging compounds
  • — Retains beneficial minerals like calcium and magnesium rather than stripping them
Watch-outs
  • — Filters last about 6 months or 800 gallons, shorter than some rivals
  • — Requires a spare faucet hole or drilling for the dedicated faucet
  • — Does not reduce total dissolved solids the way reverse osmosis does
$199.99 · Check Price on AmazonFull review →
Waterdrop G3P800 Tankless Reverse Osmosis System
Higher ratedRanked #1 in Best Under-Sink Water Filters
Waterdrop G3P800 Tankless Reverse Osmosis System
1 source$759as of Oct 17

The Waterdrop G3P800 is a tankless under-sink reverse osmosis system rated at 800 gallons per day. It uses three filter cartridges and an inline UV sterilizer, and needs an electrical outlet. Water Filter Guru scored it 9.21/10 after lab testing: it removed every contaminant found above health guideline levels and measured 886.54 GPD. Bob Vila praised its quick, leak-free filter changes and its 3:1 rated pure-to-drain ratio, and Reviewed noticed a clear improvement in taste. It suits city-water households that want fast, thorough purification. Well-water users, and anyone wanting minerals left in or a simple install, should look elsewhere.

Strengths
  • — Water Filter Guru measured 886.54 GPD, above the 800 GPD rating
  • — Removed every contaminant found above health guideline levels in lab tests
  • — Wastes less water than most tankless RO systems Water Filter Guru tested
Watch-outs
  • — Installation is involved; Reviewed had to hire a plumber
  • — No built-in remineralization; the add-on filter is sold and fitted separately
  • — The unit makes an audible groan when dispensing water
$759 · Check Price on AmazonFull review →

Derived means the reviewer published no score, so one was inferred from their written verdict. Everything else is a number the publisher printed. How we rank.

How they stack up

Aquasana Claryum AQ-5300+

Unlike the Clearly Filtered 3-Stage, the AQ-5300+ carries multiple NSF certifications rather than relying on third-party testing alone.

Waterdrop G3P800 Tankless Reverse Osmosis System

Unlike the Aquasana Claryum AQ-5300+, which the page recommends for keeping minerals in, the G3P800's RO membrane removes nearly all of them unless an add-on remineralization filter is fitted. It also needs an under-sink power outlet and a drain connection. At $759 it is a heavier investment than the Waterdrop 15UA or Frizzlife MP99, both recommended on this page for budget buyers.

Specs side-by-side

SpecAquasana Claryum AQ-5300+Waterdrop G3P800 Tankless Reverse Osmosis System
Filtration3-stage Claryum—
CertificationsNSF/ANSI 42, 53, 401NSF/ANSI 42, 53, 58 and 372
Contaminants Reduced99% of 77 (lead, chlorine, PFAS, pharmaceuticals)—
Filter Life6 months / 800 gallons6 months (CF), 12 months (CB), 24 months (RO)
Mineral RetentionYes (calcium, magnesium)—
FaucetDedicated brushed nickel included—
Install Time~30-45 min DIY—
FlowMax Flow (no tank)—
Dimensions12"L x 4.25"W x 12.88"H18.12 x 5.67 x 17.72 in
MaterialMetal—
Type—Tankless reverse osmosis with UV sterilizer
Rated Output—800 gallons per day
Filters—Sediment/carbon (CF), carbon block (CB), RO membrane
Rated Pure-to-Drain Ratio—3:1
Warranty—1 year
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