Waterdrop G3P600 vs G3P800 vs iSpring RO500AK-BN: tankless reverse osmosis compared

The three systems side by side

Three years of filters bring the G3P600 to $973.91 before installation and power^{1, 2}. The G3P800 is rated at 800 GPD with a 3:1 pure-to-drain ratio, against 600 GPD and 2:1^{1, 7}.

NSF lists the iSpring under NSF/ANSI 58 for TDS reduction only¹⁸. IAPMO separately lists the base WD-G3P600 and WD-G3P800 for named reductions, but their Black Faucet packages remain unmapped^19–21. The iSpring’s filters cost the most, about $170 a year^{11, 13}. All three carry a one-year warranty^{1, 3, 11, 12}.

Prices are US list prices on each maker’s site, before tax, checked on October 13, 2026. Checkout-code and subscription prices aren’t used. The three-year cost adds three years of filters to the purchase price and leaves out installation, electricity and drain water. Where a cell says a figure isn’t stated, we didn’t find it on the maker’s pages.

These links go to each brand’s own store and earn us no commission.

Which one fits which need

All three need a supply line and a drain. NSF lists iSpring RO500AK-BN for TDS reduction¹⁸. IAPMO lists the base Waterdrop models for additional named reductions^19–21. That is not proof that the Black Faucet packages and retail cartridge names match the certified configurations.

If tankless flow isn’t a must, APEC’s ROES-50 is a tank system at $230.99¹⁵. Its filters run about $55 a year if you change the pre-filters yearly and the full set every two years^{16, 17}. Its rated output falls from 50 GPD at 60 psi to 30 GPD at 50 psi¹⁵.

• Fast tankless RO for the least money: Waterdrop G3P600. It lists at $539, with manufacturer ratings of 600 GPD and 2:1 pure to drain^{1, 2}. Filters cost $144.97 a year¹. IAPMO lists the base model for named reductions, but the Black Faucet package remains unmapped^19–21. It needs an outlet, and Waterdrop doesn’t publish the power draw¹.
• Faster rated output and less drain water: Waterdrop G3P800. Waterdrop rates it at 800 GPD and 3:1 pure to drain, and lists a UV sterilizer in the box⁷. It costs $460 more than the G3P600, with the same size and one-year warranty^{1, 2, 7, 8}. IAPMO’s base-model 53 row names PFOA/PFOS, not UV or pathogen performance²¹.
• Minerals added back: iSpring RO500AK-BN. Its last stage is a coconut-shell carbon filter with added minerals for pH and taste¹¹. NSF lists this model under NSF/ANSI 58 for TDS reduction only¹⁸. It is the smallest, at 5.12 in wide and 25.0 lb¹¹. Filters run about $170 a year, power needs aren’t stated, and an opened return loses 15%^11–13.

Is the G3P800 worth $460 more?

Waterdrop rates the G3P800 at 800 GPD against 600 GPD^{1, 7}. At the tap, Waterdrop says the G3P800 fills a 6 oz cup in 5 seconds⁷. The G3P600 fills an 8 oz cup in 8 seconds¹. Scaled to 8 oz, that’s about 6.7 seconds against 8.

The bigger change is drain water. At 2:1, the G3P600 sends 1 gallon to the drain for every 2 gallons you get¹. At 3:1, the G3P800 sends 1 gallon for every 3⁷. At 3 gallons a day, the pace the filter ratings work out to, that’s about 1.5 gallons down the drain against 1. Over a year, the G3P800 sends about 180 fewer gallons to the drain. What that saves depends on your local water rate.

Everything else is close to the same. Both measure 18.11 × 5.67 × 17.73 in and weigh 32.4 lb^{1, 7}. Both faucets show TDS and filter life, and both use the same G3-N1CF and G3-N3CB filters^{1, 7}. The membranes differ: $139.99 for the G3P800 against $109.99, so its filters run $15 a year more^{1, 7, 9}. Over three years, the G3P800 costs $505 more at list prices^{1, 2, 7, 8}.

What the certification claims cover

IAPMO directly lists WD-G3P600 with WD-G3P600-RO and WD-G3P800 with WD-G3P800-RO under NSF/ANSI 58. Both rows name TDS, fluoride, cadmium, barium, radium 226/228 and lead¹⁹. The listed production rates are 2,715 and 3,145 liters per day (LPD), respectively. Those are not GPD figures or replacements for Waterdrop’s separate 600/800-GPD ratings^{1, 7, 19}.

Under NSF/ANSI 42, both base models with WD-G3-CB are listed for chlorine, taste and odor²⁰. Their NSF/ANSI 53 rows name PFOA/PFOS²¹. Both standards’ rows give 0.5 GPM and 1,100 gallons^{20, 21}. They do not supply percentage results, certify every PFAS, or establish pathogen reduction.

The reviews here cover Black Faucet packages. The reduction rows name the base models, without an explicit mapping to WD-G3P600-Black or WD-G3P800-Black^19–21. The manufacturer pages also use retail cartridge names that differ from the certificate, including G3-N3CB and G3P800-N2RO^{1, 7, 9}. Get the exact package and replacement-filter mapping before relying on a certified claim for your purchase.

The separate NSF/ANSI/CAN 372 listing covers product lead content. Its WCx suffix note allows different faucet colors, but only within that listing²². It does not establish the black packages’ reduction scope. The 58 footnote for WD-G3-CB and WD-G3-CF concerns material safety and structural integrity in the listed systems, not extra reductions¹⁹.

Earlier scoped NSF searches returned no Waterdrop model match^{4–6, 10}. That is not evidence of no certification: IAPMO is a different certifier. Waterdrop’s 99% PFOA/PFOS and lead figures remain manufacturer claims, not percentage results from these IAPMO rows^{1, 2, 7, 8, 19, 21}.

iSpring ties its NSF/ANSI 58 claim to TDS reduction and says it covers the whole system¹¹. NSF’s database confirms it: the RO500AK-BN is listed under NSF/ANSI 58, and its only reduction claim is TDS¹⁸. The up-to-98% lead figure and the claim of more than 1,000 contaminants are iSpring’s own¹¹. If you’re buying for lead, PFAS or fluoride, ask the maker for the certifier listing that names the model and that contaminant.

Filters, power and drain water

At one-time filter prices, the G3P600 comes to $539 + 3 × $144.97 = $973.91 over three years^{1, 2}. The G3P800 is $999 + 3 × $159.97 = $1,478.91^7–9. The iSpring is $692.99 + 3 × $170.00 = $1,202.99, using its $339.99 two-year filter pack^{11, 13}.

Waterdrop’s gallon ratings work out to about 3 gallons of filtered water a day^{1, 7}. If you drink and cook with more, you’ll change filters sooner. iSpring’s two-year pack means replacing the membrane at 24 months, the short end of its 24 to 36 month rating^{11, 13}. Its $132.99 one-year pack covers stages 1 and 3 but not the membrane¹⁴.

Neither maker publishes power draw, so electricity is unknown for all three^{1, 7, 11}. iSpring’s product page doesn’t say whether the RO500AK-BN needs an outlet at all¹¹. Drain water adds to your water bill at local rates, and none of these totals includes it.

Installation, warranty and returns

Each one needs a water supply line and a drain connection under the sink. Waterdrop includes the faucet, feed adapter, drain saddle and tubing, and says you can install it yourself in about 30 minutes^{1, 7}. Both Waterdrops also need an outlet under the sink^{1, 7}. iSpring calls installation DIY but doesn’t give the drain hardware, faucet-hole size or pressure limits¹¹.

Neither Waterdrop product page gives water limits^{1, 7}. Waterdrop’s extended-warranty terms call for city water at 14.5 to 87 psi and 41 to 100°F³. TDS must be under 750 ppm and hardness under 7 grains per gallon, and well water needs pre-filtration³. Check those against your water report before you buy either Waterdrop.

All three have a one-year warranty, and iSpring’s requires registration^{1, 7, 11, 12}. Waterdrop takes returns for 30 days with no restocking fee³. You must disassemble and repack the unit, and you pay return shipping unless it’s defective³. iSpring refunds an opened item within 30 days only if it’s unused, and keeps 15%¹². Neither policy says whether an installed system can come back^{3, 12}.

Sources

1. Waterdrop G3P600 Undersink Tankless Reverse Osmosis System - Black Faucet Waterdrop · manufacturer
2. G3P600 Black Faucet listing on Waterdrop's store (price, regular price, SKU, availability and photo descriptions) Waterdrop · manufacturer · price read from the store’s product data
3. Service Policy (returns, warranty and price match) Waterdrop · manufacturer
4. NSF listings: drinking water treatment units, trade name Waterdrop NSF · certifier
5. NSF listings: drinking water treatment units, trade name G3P600 NSF · certifier
6. NSF listings: NSF/ANSI 58 reverse osmosis systems, trade name Waterdrop NSF · certifier
7. Waterdrop G3P800 Undersink Tankless Reverse Osmosis System - Black Faucet Waterdrop · manufacturer
8. G3P800 Black Faucet listing on Waterdrop's store (price, regular price, SKU, availability and photo captions) Waterdrop · manufacturer · price read from the store’s product data
9. WD-G3P800-N2RO Filter for Waterdrop G3P800 Reverse Osmosis Systems | 800GPD Waterdrop · manufacturer
10. NSF listings: drinking water treatment units, trade name G3P800 NSF · certifier
11. iSpring RO500AK-BN NSF Certified Tankless Reverse Osmosis Water Filtration System iSpring · manufacturer
12. Refund policy (returns and warranty) iSpring · manufacturer
13. iSpring F7-RO500AK NSF/ANSI 58 Certified 2-Year Replacement Filter Pack for RO500AK Tankless Reverse Osmosis Water Filtration System iSpring · manufacturer
14. iSpring F3-RO500AK NSF/ANSI 58 Certified 1-Year Replacement Filter Pack for RO500 Series Tankless Reverse Osmosis Water Filtration System iSpring · manufacturer
15. ROES-50 - Essence 5-stage 50 GPD Reverse Osmosis Water System for Drinking Water, WQA Certified APEC Water Systems · manufacturer
16. APEC RO Replacement Filters Pre-filter Set for All ESSENCE Reverse Osmosis Systems (Stages 1-3) APEC Water Systems · manufacturer
17. APEC RO Replacement Filters Complete Filter Set for ESSENCE ROES-50 System (Stages 1-5) APEC Water Systems · manufacturer
18. NSF listings: drinking water treatment units, trade name RO500AK (iSpring RO500AK-BN and RO500AK-ORB, NSF/ANSI 58, TDS reduction) NSF · certifier
19. IAPMO R&T WC-13976: Waterdrop G3P600/G3P800, NSF/ANSI 58, checked October 15, 2026 IAPMO R&T · certifier
20. IAPMO R&T WC-14301: Waterdrop G3P600/G3P800, NSF/ANSI 42, checked October 15, 2026 IAPMO R&T · certifier
21. IAPMO R&T WC-14805: Waterdrop G3P600/G3P800, NSF/ANSI 53, checked October 15, 2026 IAPMO R&T · certifier
22. IAPMO R&T WC-13977: Waterdrop G3P600/G3P800, NSF/ANSI/CAN 372, checked October 15, 2026 IAPMO R&T · certifier