Bottom line: The Waterdrop G3P800 is a tankless under-sink reverse osmosis system certified to NSF/ANSI 58 (reverse osmosis performance) and NSF/ANSI 372 (lead-free materials). Reverse osmosis at this membrane grade removes >99% of microplastics and nanoplastics across the measured size range. If you own your home and want filtered water permanently on tap without a countertop appliance, this is the best-per-dollar pick in the 2026 water filter lineup.

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Waterdrop G3P800 under-sink RO

What It Actually Removes

The G3P800 is a 7-stage system. The stage that matters for microplastics is the RO membrane, with an effective pore size of roughly 0.0001 microns — about 100,000× smaller than the smallest microplastic fragments documented in tap water studies. At that scale, particle removal is essentially complete.

  • Microplastics & nanoplastics: >99% removal across measured size ranges (this is intrinsic to RO membrane chemistry, not a marketing claim).
  • PFAS (“forever chemicals”): RO removes the long-chain PFAS species and substantially reduces short-chain.
  • Lead, chromium, fluoride, arsenic: all reduced by the membrane stage.
  • TDS (total dissolved solids): the unit’s smart display shows input and output TDS so you can verify the membrane is working in real time.
  • What RO does not fix: chlorine taste (handled by the carbon prefilter), bacteria (RO blocks most but isn’t NSF-certified for microbiological reduction — if your source is well water with pathogens, you need a UV stage too).

What It Costs to Run

CostApprox. value
Unit price$500–700 (varies with sales)
Filter replacements per year~$150 at recommended intervals
InstallDIY 1–2 hours, or ~$200 plumber
Water waste ratio~3:1 (3 gal filtered per 1 gal waste) — better than legacy tank RO at ~4:1
Faucet holeRequires a countertop hole (or repurpose a soap dispenser slot)

The big architectural difference from older RO units is tankless operation. Conventional RO needs a 2–4 gallon pressurized storage tank under the sink that holds pre-filtered water. The G3P800 produces 800 gallons per day on demand, so there’s no tank — the cabinet space stays usable, and you don’t get the “stale tank water” complaint older RO owners report.

Where It Sits vs. Countertop RO

Waterdrop G3P800AquaTru Countertop
InstallPlumbing + faucet holeNone — plug in
Renter-friendlyNoYes
On-demand flowYes (tankless, 800 GPD)No — fill the reservoir (~15 min/gal)
Counter spaceZeroBreadbox-sized
Filter cost/yr~$150~$110
NSF certification58, 37242, 53, 58, 401, P473

AquaTru wins on certifications (especially P473 — the microplastic-specific standard) and on renter-friendliness. The G3P800 wins on counter space and on flow rate — RO water from the tap, not from a reservoir. We have a dedicated AquaTru microplastics review if you’re cross-shopping.

What You Can Do

  1. If you own your home and want set-and-forget filtration, the Waterdrop G3P800 is the pick. Install once, then forget about it for ~6 months at a time.
  2. If you rent or can’t drill a faucet hole, the AquaTru countertop RO gives you the same microplastic-removal grade with zero install.
  3. If you’re not sure which RO category fits, the full water filter comparison guide walks through pitcher, countertop, and under-sink options across price points.

Frequently Asked Questions

Does the Waterdrop G3P800 remove microplastics?
Yes. The G3P800 uses a reverse osmosis membrane with an effective pore size around 0.0001 microns — far smaller than the smallest microplastics or nanoplastics documented in drinking water studies. RO at this grade removes >99% of plastic particles by size exclusion. The unit is NSF/ANSI 58 certified for overall RO performance.
Is the Waterdrop G3P800 NSF certified for microplastics specifically?
It carries NSF/ANSI 58 (reverse osmosis) and NSF/ANSI 372 (lead-free materials) certifications. It does not carry the microplastic-specific NSF/ANSI P473 — which AquaTru does. The underlying RO chemistry removes microplastics at the same efficiency in both units; the difference is which removal claims have been independently verified through third-party testing.
How much does it cost to run per year?
Roughly $150/year in filter replacements at the recommended change intervals. The carbon prefilter changes every 6–12 months, the RO membrane every 2 years. The unit’s smart display tracks remaining filter life so you don’t have to guess.
Can I install it myself?
Most owners install it themselves in 1–2 hours. You need a hole in the countertop or sink for the dedicated faucet (or you can repurpose a soap dispenser slot), plus a tap into the cold water line under the sink. If you’re not comfortable with basic plumbing, a plumber will install it for ~$200.
Does it waste a lot of water?
The G3P800 has roughly a 3:1 efficiency ratio — 3 gallons filtered for every 1 gallon sent to drain. That’s notably better than older RO systems, which ran 4:1 or worse. For a typical household, the additional water use is small compared to other household draws (laundry, dishwasher, lawn).

For the bigger picture on why RO outperforms carbon-block and pitcher filters for microplastics specifically, see our deep dive on microplastics in human blood and the full water filter buying guide.

This article is for informational purposes only and does not constitute medical advice.

Source: NSF International product certification listings; manufacturer specifications; Waterdrop G3P800 NSF/ANSI 58 and 372 certification documents.