iSpring
iSpring RO500AK-BN Tankless Reverse Osmosis System
Tankless 500 GPD reverse osmosis with an alkaline stage, NSF 58 certified for TDS
$692.99
Compare with this one →Our under-sink reverse osmosis pick
WaterdropG3P600
Fast tankless RO with a TDS faucet, but its certification claims are unconfirmed
Source-based analysis, not hands-on testing. Our method
Cofounder of Superhuman Chambers · About the author.
The verdict
The G3P600 is a tankless RO system that Waterdrop rates at 600 GPD, with a faucet that shows TDS. It lists at $539, and filters run about $145 a year. The catch: NSF has no listing for it, and the PFAS and fluoride claims come without test data.
The trade-off
No certifier listing was found for the contaminant claims, the warranty is one year, and the power draw isn't published.
Model reviewed: G3P600 Black Faucet / WD-G3P600-Black
$539
Check price at Waterdrop US price, checked
No affiliate commission on this link. Check the exact variant before buying.
About this price
List price on Waterdrop's online store on Oct 13, 2026, before tax: $539.00 for SKU WD-G3P600-Black, with no markdown, shown as available. The page's code also gives the price as $539.00. The product page shows $439.00 next to a struck-through $539.00 and a "$100 Off" tag. That price needs code WDG3P600B at checkout and is labeled a member offer, so it isn't recorded here. The black-faucet version is the only variant. The old review recorded $439 on Oct 10, 2026. The page advertises free shipping and delivery in 3 to 5 business days.
A GOOD FIT FOR
A kitchen on city water with a drain and an outlet under the sink, if you want fast RO water without a tank.
- A kitchen on municipal water with a cold line, a drain and an outlet under the sink
- You want fast tankless RO water and a faucet that shows TDS and filter life
- A household that uses about 3 gallons of filtered water a day or less, the pace the filter ratings assume
- You're comfortable installing it yourself with the included drain saddle and feed adapter
THINK TWICE IF
- You need certified reduction of PFAS, fluoride or lead, since no certifier listing for those was found
- You're on well water without pre-filtration, or your water is above 750 ppm TDS or 7 grains per gallon hardness
- There's no outlet under your sink
- You want more than a one-year warranty
What still needs checking
- 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
The practical details.
| Exact variant | G3P600 Black Faucet / WD-G3P600-Black |
|---|---|
| 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 |
| Dimensions | 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. |
| Materials | 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. |
Before you buy
InstallationIt goes under the sink and needs a cold-water supply, a drain and an outlet
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.
WarrantyOne-year warranty covering manufacturing defects, per the product page
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.
Returns30-day returns from receipt with no restocking fee, for orders within the continental US
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.
More about this assessment
The Waterdrop G3P600 is a tankless under-sink reverse osmosis system with a black smart faucet that shows TDS and filter life. Waterdrop rates it at 600 GPD with a 2:1 pure-to-drain ratio, and it needs a cold-water line, a drain and an outlet. It lists at $539, and its three filters cost $144.97 a year on Waterdrop's time schedule. That's about $974 over three years, before installation, power and water. The catch is that NSF's database has no G3P600, and the PFAS and fluoride claims come without published test data. The warranty is one year, and Waterdrop doesn't publish the power draw.
Strengths on paper
- Waterdrop rates it at 600 GPD and says it fills an 8 oz cup in 8 seconds
- 2:1 pure-to-drain ratio
- Tankless, so there's no storage tank to fit under the sink
- The faucet shows TDS and filter life
- The kit includes the faucet, feed adapter, drain saddle, tubing and power adapter
- Filter prices are published: $29.99, $29.99 and $109.99, or $144.97 a year on the time schedule
- No restocking fee on returns within 30 days
- Waterdrop refunds the difference if its own price drops within 30 days
Limitations
- The $439 shown on the page needs a promo code, so the list price is $539
- NSF lists no G3P600, and Waterdrop doesn't name who certifies its NSF/ANSI 42 and 58 claims
- The PFAS, fluoride and 99% PFOA and PFOS claims come without published test data
- Needs electricity, and Waterdrop doesn't publish the power draw
- The filter gallon ratings work out to about 3 gallons a day, so heavier use means more frequent changes
- One-year warranty, and the extended warranty's length and price aren't published
- You pay return shipping unless it's defective, and the unit must be disassembled and repacked
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
$973.91Incomplete: 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. One-time price on the G3P600 product page on Oct 13, 2026, or $28.49 on subscription. Waterdrop rates it for up to 6 months or 550 gallons.
- G3-N3CB filter: $29.99 every 12 months. One-time price on the G3P600 product page on Oct 13, 2026, or $28.49 on subscription. Waterdrop rates it for up to 12 months or 1,100 gallons.
- G3P600-RO filter: $109.99 every 24 months. One-time price on the G3P600 product page on Oct 13, 2026, or $104.49 on subscription. Waterdrop rates it for up to 24 months or 2,200 gallons.
- Purchase is the $539.00 list price on Waterdrop's online store on Oct 13, 2026, before tax. The $439.00 shown with code WDG3P600B would cut the three-year total by $100.
- Filters on Waterdrop's time schedule: two G3-N1CF at $29.99, one G3-N3CB at $29.99 and half a G3P600-RO at $109.99 each year. That's $59.98 + $29.99 + $55.00 = $144.97 a year at one-time prices, or $137.72 on subscription. Waterdrop's compare table shows the same $144.97 average annual cost.
- Three years at list price comes to $539 + 3 × $144.97 = $973.91, before installation, power and water.
- The gallon ratings (550, 1,100 and 2,200 gallons) work out to about 3 gallons of filtered water a day. If you use more, you'll replace filters sooner and pay more.
- Installation is unknown. Waterdrop says it's a 30-minute job without a plumber, and plumber labor isn't priced.
- Energy is unknown because Waterdrop doesn't publish the power draw. Drain water at the 2:1 ratio adds to your water bill, but that depends on local rates and isn't estimated.
- No subscription is required, 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 database lists no G3P600 and no Waterdrop reverse osmosis system under NSF/ANSI 58.46 Checked on Oct 13, 2026. A trade-name search for G3P600 and a Waterdrop search limited to NSF/ANSI 58 both returned "No Matching Products Found." The Waterdrop listings that could be read are refrigerator, faucet-mount, pour-through and plumbed-in filters under NSF/ANSI 42, 53 and 401. So NSF doesn't list the G3P600 under either name. That doesn't rule out a listing with IAPMO R&T or WQA. IAPMO's directory couldn't be searched, and WQA's wasn't checked.
- Manufacturer claimWaterdrop lists NSF/ANSI 42, 58 and 372 for the G3P600. One product image is labeled as an IAPMO R&T certificate for NSF/ANSI/CAN 372.12 NSF/ANSI 372 covers the lead content of parts that touch water, not what the filters remove. The page doesn't name a certifier for NSF/ANSI 42 or 58 or list certified reductions. It doesn't claim NSF/ANSI 53, 401 or 473 for this model.
- Manufacturer claimWaterdrop says the G3P600 reduces TDS, PFAS, fluoride, heavy metals and chlorine. A product image claims 99% reduction of PFOA and PFOS.12 The page gives no test standard, lab, challenge level or per-contaminant results.
- Manufacturer claimWaterdrop rates the G3P600 at 600 GPD with a 2:1 pure-to-drain ratio, and says it fills an 8 oz cup in 8 seconds.1 Manufacturer ratings. Waterdrop doesn't state the test conditions, such as feed pressure or water temperature.
Sources (6)
- Waterdrop G3P600 Undersink Tankless Reverse Osmosis System - Black Faucet Waterdrop · manufacturer · checked Oct 13, 2026
- G3P600 Black Faucet listing on Waterdrop's store (price, regular price, SKU, availability and photo descriptions) Waterdrop · manufacturer · data file · checked Oct 13, 2026
- Service Policy (returns, warranty and price match) 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 G3P600 NSF · certifier · checked Oct 13, 2026
- NSF listings: NSF/ANSI 58 reverse osmosis systems, trade name Waterdrop 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 →