Our under-sink reverse osmosis pick
Waterdrop G3P600
Fast tankless RO with a TDS faucet, but its certification claims are unconfirmed
$539
Compare with this one →Under sink reverse osmosis
WaterdropG3P800
Fast tankless RO with a 3:1 drain ratio and unconfirmed certification
Source-based analysis, not hands-on testing. Our method
Cofounder of Superhuman Chambers · About the author.
The verdict
The G3P800 is a fast tankless RO system for a kitchen with a drain and an outlet under the sink. It's $999, or $849 with a checkout code, and filters run about $160 a year. The catch: NSF doesn't list it, and the page text doesn't say who certified its NSF/ANSI claims.
The trade-off
NSF doesn't list it, Waterdrop doesn't publish the power draw, and the warranty is one year.
Model reviewed: G3P800 Black Faucet / WD-G3P800-Black
$999
Check price at Waterdrop US price, checked
No affiliate commission on this link. Check the exact variant before buying.
About this price
Store price on Oct 13, 2026, before tax. Waterdrop's online store lists the WD-G3P800-Black at $999.00 with no markdown, so there's no store sale. The product page shows $849.00 next to a struck-through $999.00 and a "$150 Off" tag. That price needs code WDG3P800B at checkout, so it isn't used here. The black faucet is the only option on the page. It shows as in stock, with free US shipping and delivery in 3 to 5 business days. If Waterdrop's own price drops within 30 days of purchase, it refunds the difference.
A GOOD FIT FOR
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
- You want fast tankless RO flow, rated at 800 GPD
- You want less drain water than the 2:1 G3P600 sends
- You like seeing TDS and filter life on the faucet
- A household that drinks and cooks with up to about 3 gallons of filtered water a day, which matches the rated filter lives
THINK TWICE IF
- You need certified reduction of lead, PFAS or fluoride confirmed in a certifier database
- You're on well water and don't want to add pre-filtration
- There's no outlet under your sink
- You want alkaline remineralization, which Waterdrop's comparison table marks as not included
- You want more than a one-year warranty
What still needs checking
- 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
The practical details.
| Exact variant | G3P800 Black Faucet / WD-G3P800-Black |
|---|---|
| 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 |
| 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. |
| 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. |
Before you buy
InstallationIt goes under the sink and connects to a water supply line, a drain and its own faucet
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.
WarrantyOne year against manufacturing defects, per the product page
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.
Returns30-day returns, counted from receipt, for orders within the continental US
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.
More about this assessment
The Waterdrop G3P800 is a tankless under-sink reverse osmosis system with a black faucet that shows TDS and filter life. Waterdrop rates it at 800 GPD with a 3:1 pure-to-drain ratio. It's $999, or $849 with a checkout code, and filters average $159.97 a year at Waterdrop's prices. It needs a drain and an outlet under the sink, and the warranty is one year. The catch is certification: the page text names no certifier, and NSF's databases have no G3P800 listing.
Strengths on paper
- Rated at 800 GPD, and Waterdrop says it fills a 6 oz cup in 5 seconds
- A 3:1 pure-to-drain ratio, against 2:1 on the cheaper G3P600
- No storage tank, and its narrowest side is 5.67 in
- The faucet shows TDS and filter life
- Filters cost $159.97 a year at Waterdrop's prices, and the membrane is rated for up to 24 months
- The box includes the faucet, drain saddle, feed adapter and tubing for a DIY install
- Waterdrop refunds the difference if its own price drops within 30 days of purchase
Limitations
- The page text names no certifier, and NSF's databases have no G3P800 listing
- The certification list changes across the page: 42, 58 and 372 in one place, with 53 added in the spec table
- The page gives no test standard or per-contaminant results for the PFAS, lead and fluoride claims
- The $849 price needs a checkout code; the store price is $999
- It needs an outlet, and the power draw isn't published
- One-year warranty, and the extended terms exclude filters and well-water damage
- Returns must be disassembled and repacked as received, and you pay return shipping unless it's defective
- No G3P800-specific water limits on the product page, and the linked manual PDF has no searchable text
What it costs to own.
Adjust the assumptions for your use. Missing costs stay unknown.
PLAN YOUR OWNERSHIP COSTS
What will it cost to own?
Change the assumptions to fit your use. Leave an unknown cost blank. Add water, subscriptions, cleaning, shipping and taxes if they apply. Use average operating power, not the maximum rating.
3-year known subtotal
$1,478.91Incomplete: installation, energy use. This is not the full ownership cost.
Energy component: Unknown
Purchase + installation + years × (annual consumables + annual other) + watts/1000 × hours/day × 365 × years × $/kWh. Annualized allowances, not an exact replacement schedule. Excludes taxes, shipping, finance and resale unless entered.Replacement parts & cost assumptions
Recorded recurring parts and refills:
- G3-N1CF filter: $29.99 every 6 months. Price on the G3P800 product page on Oct 13, 2026. Rated for up to 6 months or 550 gallons. Optional autoship is $28.49 every 6 months.
- G3-N3CB filter: $29.99 every 12 months. Price on the G3P800 product page on Oct 13, 2026. Rated for up to 12 months or 1,100 gallons. Optional autoship is $28.49 every 12 months.
- G3P800-N2RO reverse osmosis membrane: $139.99 every 24 months. One-time price on the filter's own page on Oct 13, 2026, matching the system page. Optional autoship is $132.99 every 24 months. The filter page gives 2,200 gallons in its specs but says "up to 2,900 gallons" elsewhere. Waterdrop lists it for the G3P800.
- MNR35 and ALK35 add-on filters (optional): cost not recorded. The G3P800 page also lists two more filters at $29.99 each. The MNR35 is rated for up to 12 months or 1,100 gallons, and the ALK35 for up to 6 months or 550 gallons. The page doesn't say whether the G3P800 needs them, and Waterdrop's $159.97 average annual cost leaves them out, so they aren't counted here.
- Purchase is the $999 store price on Oct 13, 2026, before tax. With code WDG3P800B at checkout, the product page shows $849.
- Yearly filters: two G3-N1CF at $29.99 ($59.98), one G3-N3CB at $29.99 and half of a $139.99 G3P800-N2RO membrane ($69.995). That's $159.965, rounded to $159.97, the same average annual cost Waterdrop's comparison table gives.
- Those timed lives work out to about 3 gallons of filtered water a day (550 gallons in 6 months). Use more and you'll reach the gallon limits first and spend more.
- Optional autoship cuts the same filters to $28.49, $28.49 and $132.99, or $151.97 a year.
- Installation is unknown. Waterdrop sells it as a DIY install, and plumber labor isn't priced.
- Energy is unknown. It needs an outlet, but Waterdrop doesn't publish its power draw.
- Drain water adds to your water bill. At 3:1, about 1 gallon goes down the drain for every 3 gallons you get, and the cost depends on local rates.
- There's no required subscription, so other yearly costs are $0.
Evidence & sources.
Do water filters work? Our evidence review grades the research as Strong. That grade is about the claim, not about this product.
- CertificationNSF's drinking water treatment unit listings have no G3P800. A trade-name search for G3P800 returned "No Matching Products Found". Waterdrop's listings, under Qingdao Ecopure Filter Co., cover only NSF/ANSI 42, 53 and 401. They're for refrigerator, faucet-mount, pour-through and plumbed-in filters, with no reverse osmosis or NSF/ANSI 58 entries. A Waterdrop search of NSF's drinking water system component listings also returned no matching products.5689 NSF/ANSI 58 is NSF's standard for reverse osmosis systems. This rules out an NSF listing, not certification by CSA, IAPMO or WQA, whose directories couldn't be checked.
- Manufacturer claimWaterdrop says the G3P800 meets NSF/ANSI 42, 58 and 372 standards. Its spec and comparison tables list NSF/ANSI 42, 53, 58 and 372. Product image captions describe an NSF/ANSI/CAN 372 certificate and SGS and CSA testing. The G3P800-N2RO membrane page lists "WQA" in its spec table.124 The page text gives no certifier, certificate number or certified contaminant list for any of these claims. It doesn't say what the 372 claim covers.
- Manufacturer claimWaterdrop says the G3P800 removes PFAS, fluoride, lead, chromium and heavy metals, including up to 99% of PFOA and PFOS. An image caption claims more than 99% lead reduction. Waterdrop says the 0.0001 μm membrane reduces over 1,000 contaminants.12 These are Waterdrop's own claims. An image caption mentions SGS and CSA testing, but the page text gives no test standard, challenge level or per-contaminant result.
- Manufacturer claimWaterdrop rates output at 800 GPD with a 3:1 pure-to-drain ratio and says it fills a 6 oz cup in 5 seconds.14 Manufacturer ratings with no stated test pressure, temperature or feed-water TDS. Output and drain volume vary with those conditions.
Sources (9)
- Waterdrop G3P800 Undersink Tankless Reverse Osmosis System - Black Faucet Waterdrop · manufacturer · checked Oct 13, 2026
- G3P800 Black Faucet listing on Waterdrop's store (price, regular price, SKU, availability and photo captions) Waterdrop · manufacturer · data file · checked Oct 13, 2026
- Service Policy (returns, warranty, shipping and price match) Waterdrop · manufacturer · checked Oct 13, 2026
- WD-G3P800-N2RO Filter for Waterdrop G3P800 Reverse Osmosis Systems | 800GPD Waterdrop · manufacturer · checked Oct 13, 2026
- NSF listings: drinking water treatment units, trade name Waterdrop NSF · certifier · checked Oct 13, 2026
- NSF listings: drinking water treatment units, trade name G3P800 NSF · certifier · checked Oct 13, 2026
- WD-G3P800 user manual (PDF linked from the product page, no searchable text) Waterdrop · manufacturer · checked Oct 13, 2026
- NSF listings: drinking water system components, trade name Waterdrop NSF · certifier · checked Oct 13, 2026
- NSF Standards for Water Treatment Systems NSF · certifier · checked Oct 13, 2026
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Compare with this one →About this review. The facts on this page come from manufacturer pages and certification listings, checked Oct 13, 2026. The sources are listed above.
Our editorial policy →