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Under sink reverse osmosis

Waterdrop G3P800

G3P800 Black Faucet / WD-G3P800-Black

$999US price, checked Oct 13, 2026

Fast tankless RO with a 3:1 drain ratio and unconfirmed certification

Check price at Waterdrop Full review →

Our under-sink reverse osmosis pick

Waterdrop G3P600

G3P600 Black Faucet / WD-G3P600-Black

$539US price, checked Oct 13, 2026

Fast tankless RO with a TDS faucet, but its certification claims are unconfirmed

Check price at Waterdrop Full review →

Criterion	Waterdrop G3P800	Waterdrop G3P600
US price	$999Checked Oct 13, 2026 · Price details in the review	$539Checked Oct 13, 2026 · Price details in the review
Three-year ownership estimate	$1,478.91 Incomplete known subtotal. Not included: installation, energy use.	$973.91 Incomplete known subtotal. Not included: installation, energy use.
Choose if	A household on city water that wants quick RO flow and less drain water than a 2:1 system.	A kitchen on city water with a drain and an outlet under the sink, if you want fast RO water without a tank.
Main trade-off	NSF doesn't list it, Waterdrop doesn't publish the power draw, and the warranty is one year.	No certifier listing was found for the contaminant claims, the warranty is one year, and the power draw isn't published.
Key specifications	Rated output: 800 GPD; Waterdrop says it fills a 6 oz cup in 5 seconds Pure-to-drain ratio: 3:1 Filter life: G3-N1CF 6 months or 550 gal, G3-N3CB 12 months or 1,100 gal, G3P800-N2RO membrane 24 months or 2,200 gal Certification claim: NSF/ANSI 42, 58 and 372 in the feature list, plus 53 in the spec table. No certifier named in the page text, and no NSF listing found Power: Needs an outlet (adapter included); wattage not published Faucet: Smart display with TDS and filter-life readout Size and weight: 18.11 × 5.67 × 17.73 in (axes not labeled), 32.4 lb	Rated output: 600 GPD, and Waterdrop says it fills an 8 oz cup in 8 seconds Pure-to-drain ratio: 2:1 Filters: 8-stage. Three replacement filters: G3-N1CF (6 months or 550 gal), G3-N3CB (12 months or 1,100 gal), G3P600-RO (24 months or 2,200 gal) Certification: Waterdrop lists NSF/ANSI 42, 58 and 372. NSF has no G3P600 listing, and IAPMO's directory couldn't be checked Power: Needs an outlet. Power adapter included, wattage not published Water limits: Municipal water, 14.5 to 87 psi, 41°F to 100°F, pH 6.5 to 8.5, TDS under 750 ppm, hardness under 7 gpg (from the extended-warranty terms) Size and weight: 18.11 × 5.67 × 17.73 in, 32.4 lb
Exact variant	G3P800 Black Faucet / WD-G3P800-Black	G3P600 Black Faucet / WD-G3P600-Black
Dimensions	18.11 × 5.67 × 17.73 in and 32.4 lb, per Waterdrop's product page. Waterdrop doesn't say which measurement is width, depth or height, or how much clearance you need to swap filters.	18.11 × 5.67 × 17.73 in and 32.4 lb, per the product page's spec table. Waterdrop doesn't say which figure is width, depth or height, or how much clearance you need to swap filters.
Installation	It goes under the sink and connects to a water supply line, a drain and its own faucet. The box includes the faucet, a 3/8 to 1/2 in feed-water adapter, a 1/4 in drain saddle, tubing, lock clips and Teflon tape. It also needs an outlet, and a power adapter comes in the box. Waterdrop calls it a 30-minute DIY install that needs no plumbing skills. It's for indoor use only. The product page doesn't give the faucet-hole size or any water limits, and the linked user manual PDF has no searchable text. The only limits Waterdrop publishes are general ones in its extended-warranty terms, not specific to the G3P800. They call for municipal tap water at 14.5 to 87 psi and 41 to 100°F. TDS should be under 750 ppm and hardness under 7 grains per gallon. Well water needs pre-filtration.	It goes under the sink and needs a cold-water supply, a drain and an outlet. The kit includes the faucet, a 3/8 in to 1/2 in feed water adapter, a 1/4 in drain saddle, 3/8 in and 1/4 in tubing, lock clips, Teflon tape and a power adapter. Waterdrop says installation takes about 30 minutes and doesn't need a plumber. The product page doesn't give the faucet-hole size or any water limits. Waterdrop's extended-warranty terms do. They call for municipal tap water at 14.5 to 87 psi. Inlet water should be 41°F to 100°F, with a pH of 6.5 to 8.5. TDS must be under 750 ppm and hardness under 7 grains per gallon. Well water needs pre-filtration. It's for indoor use only.
Materials	A tankless unit that Waterdrop calls 10-stage, built around three replaceable filters: the G3-N1CF, the G3P800-N2RO reverse osmosis membrane and the G3-N3CB. The membrane page describes this as a 3-filter setup with a seven-layer RO membrane. Waterdrop says the membrane is 0.0001 μm, though the membrane page's FAQ says 0.001 microns. The box list includes a UV sterilizer, and the faucet's display shows TDS and filter life. Waterdrop's comparison table marks alkaline mineralization as not included. Housing, tubing and faucet materials aren't listed.	Tankless RO system with 8 stages, including a 0.0001 µm RO membrane. Waterdrop lists three replacement filters for it: G3-N1CF, G3-N3CB and G3P600-RO. The box holds the system, filters, faucet, power adapter, tubing and fittings. Waterdrop doesn't list the housing, tubing or faucet materials, or the media in each stage.
Warranty	One year against manufacturing defects, per the product page. Waterdrop's service policy says most of its RO systems carry a one-year limited warranty and that terms vary by model. If it fails from a quality problem during the warranty, Waterdrop will take it back, repair it or replace it for free. The policy's extended-warranty terms apply only to purchases from Waterdrop's US website. They exclude filters and damage from well or river water. They also exclude damage from incorrect installation, use or maintenance, or from unauthorized repairs. The policy asks you to report a defect within 30 days of finding it. It doesn't say how the extended terms relate to the standard one-year warranty. Waterdrop also offers lifetime technical support for eligible models.	One-year warranty covering manufacturing defects, per the product page. Waterdrop's service policy says most of its RO systems get a one-year limited warranty and that terms vary by model. For a defect under warranty, Waterdrop says it can take a free return, repair the unit or send a replacement. For a damaged or wrong item, you email Waterdrop with your order details and a photo. Waterdrop also sells an extended warranty, only for products bought on its US site. It doesn't publish the length or price. The extended warranty excludes filters, products bought outside authorized Waterdrop channels, and damage from parts or filters Waterdrop didn't sell. It also requires municipal tap water at 14.5 to 87 psi and 41°F to 100°F. TDS must be under 750 ppm and hardness under 7 grains per gallon.
Returns	30-day returns, counted from receipt, for orders within the continental US. Items must be disassembled and repacked as received, in the original packaging with the receipt. There's no restocking fee within 30 days, but you pay return shipping unless the return is for a quality problem. After 30 days, Waterdrop charges a 10% restocking fee and deducts shipping from the refund. An item that isn't like new also carries a 10% fee. If it arrives damaged or wrong, email service@waterdropfilter.com with your order details and a photo. Orders from Amazon and other third-party sellers aren't covered. The policy doesn't say whether an installed system counts as like new.	30-day returns from receipt with no restocking fee, for orders within the continental US. Items must be disassembled and repacked the way they arrived. You pay return shipping unless the problem is a quality defect. After 30 days, or for items not in like-new condition, Waterdrop charges a 10% restocking fee. After 30 days it also deducts shipping from the refund. Refunds are processed within 5 working days of inspection. Orders from third-party sellers, including Amazon, don't qualify. If Waterdrop's own price drops within 30 days of purchase, it refunds the difference.
Unresolved questions	Which body, if any, certifies the G3P800 to NSF/ANSI 42 or 58, and which contaminants a listing covers Who issued the NSF/ANSI/CAN 372 certificate shown in a product image, and what it covers Whether the NSF/ANSI 53 claim in the spec table holds, since the feature list leaves it out What SGS and CSA tested, to which standard, and the results behind the PFOA, PFOS and lead reduction claims What the WQA entry on the membrane's page refers to Power draw and how long the pump runs each day G3P800-specific pressure, temperature and feed-water TDS limits Faucet-hole size and clearance needed for filter changes Which of the three listed dimensions is the width What the $89.97 G3P800 replacement-filter combo linked from the membrane page contains Whether an installed system can be returned Real output and drain volume at your water pressure and temperature	Who certifies the NSF/ANSI 42 and 58 claims, and which contaminants a listing covers The system's power draw The membrane's TDS rejection rate The faucet-hole size Which dimension is width, depth or height Whether the MNR35 and ALK35 filters shown on the page fit the G3P600 Length and price of the extended warranty Actual output and drain water at your water pressure and temperature

These comparisons use published specifications, not head-to-head tests. Prices and terms are dated. Unknown costs are not zero. Check the exact variant before you buy.