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Waterdrop G3 Tankless Reverse Osmosis System (400 GPD)
$579.00$521.10
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- ✓ 120 Day No Hassle Returns
- ✓ No Sales Tax On All Orders (Outside of MN)
Waterdrop G3: the original 400 GPD tankless reverse osmosis system
The Waterdrop G3 is the model that made tankless under-sink RO mainstream: 400 gallons per day (a glass in about 12 seconds), a 1:1 pure-to-drain ratio, NSF/ANSI 58 and 372 certification, and the same smart TDS-and-filter-life faucet as the G3P600 and G3P800. It suits one- and two-person households, and anyone replacing a slow tank-style RO who doesn't need the faster fill of the newer models. Note the current pricing: the G3P600 is $40 less and faster, so the G3 is the right pick mainly when you want the original, proven design or it's in stock when the others aren't; the G3P800 adds UV.
- 400 GPD (0.28 GPM), booster pump, no storage tank; fills a 12 oz glass in ~12 seconds
- 1:1 pure-to-drain, about a quarter of the waste of a tank-style RO
- 7-stage filtration; NSF/ANSI 58 (up to 91.9% TDS reduction) and 372 (lead-free) certified; 400+ chemical lab tests
- Smart faucet shows TDS and filter life; tool-free twist-out cartridges; automatic flushing
- Authorized Waterdrop dealer: Waterdrop's own pricing, free shipping, 120-day returns, no sales tax outside Minnesota
Specs, what it removes, replacement filters, install requirements and the G3 vs G3P600 vs G3P800 comparison are below. Questions before you buy: 800-374-2143.
What it removes
Seven stages: sediment and carbon pre-filter, RO membrane, and a coconut-shell carbon block post-filter. Certified TDS reduction to NSF/ANSI 58, and tested reduction of:
- Chlorine, chloramine, taste and odor, scale, turbidity
- Lead, mercury, arsenic, chromium (hexavalent and trivalent), cadmium, barium, copper, aluminum, radium 226/228
- Fluoride, nitrite, cysts
- PFOA and PFOS, benzene, formaldehyde, bisphenol A, chlordane, asbestos and other organics
Bacteria and viruses are not a listed claim on the G3; the G3P800 adds a UVC-LED stage for that.
Specifications
| Model | WD-G3-W |
| Output | 400 GPD (0.28 GPM) |
| Pure : drain | 1:1 |
| Certification | NSF/ANSI 58 and 372 |
| Size (L × W × H) | 18.11″ × 5.67″ × 17.73″; 15.4 lb |
| Feed water | Municipal tap, 41–100°F, 14.5–87 psi |
| Power | Outlet required; main cable 90″, faucet cable 59″ |
| Faucet | Smart screen faucet, brushed nickel; TDS, filter life and fault alerts |
| Auto-flush | 20 s after every 2 h of use, after power restores, and 5 min after the tap closes |
Replacement filters
Three cartridges; the faucet counts down each one. The pre-filter and carbon block are shared across the G3 line, and all three are stocked here.
| Cartridge | Stage | Change every | Price |
|---|---|---|---|
| WD-G3-N1CF | Sediment + carbon pre-filter | 6 months | $40.97 |
| WD-G3-N3CB | Coconut carbon block | 12 months | $40.97 |
| WD-G3-N2RO | RO membrane | 24 months | $127.04 |
About $150 a year averaged over the membrane cycle. Optional: the WD-MNR35 remineralization cartridge adds calcium and magnesium back for taste. All cartridges: Waterdrop replacement filters.
Installation and requirements
- Power: a grounded outlet under the sink. Main cable 90″, faucet cable 59″. It usually shares the disposal or dishwasher outlet; check you have a free socket.
- Feed water: municipal tap water, 41–100°F, 14.5–87 psi. Waterdrop doesn't rate the G3 series for untreated well water; on a well, put it after your softener and iron filter, and see RO for well water or call us first.
- Holes: one 1″ hole for the smart faucet (or use the existing sprayer hole) and a drain-saddle connection on the tailpiece.
- Not for: feeding a refrigerator or ice maker from a tankless unit; use the faucet only.
- After a softener: fine for the membrane, but sodium from the softener can affect taste; a remineralization cartridge fixes it.
- Time: about 30 minutes with the included fittings, T-adapter, drain saddle and 3 × 60″ tubing.
- Filter changes: twist-out, no tools, no water shut-off; the faucet tells you when.
- What's in the box: system, smart faucet, three filters installed, PE tubing, T-fitting, drain saddle, lock clips, power adapter, manual.
Installation video
Waterdrop G3 vs G3P600 vs G3P800
| G3 | G3P600 | G3P800 | |
|---|---|---|---|
| Output | 400 GPD | 600 GPD | 800 GPD |
| Fill a 12 oz glass | ~12 s | ~8 s | ~6 s |
| Pure : drain | 1:1 | 2:1 | 3:1 |
| Filter stages | 7 | 8 | 9, with UVC-LED |
| Certification | NSF/ANSI 58 & 372 | NSF/ANSI 58 & 372 | NSF/ANSI 58 & 372 |
| Smart faucet | Yes | Yes | Yes |
| Best for | 1–2 people, lowest cost | 2–4 people; the value pick | 4+ people, or anyone who wants UV |
| Price | $579 | $539 | $849 |
Frequently asked questions
Should I buy the G3 or the G3P600? At current prices the G3P600 costs less and fills 50% faster with half the drain water, so it's the better buy for most kitchens. Choose the G3 if you specifically want the original 400 GPD design.
Is the Waterdrop G3 NSF certified? Yes: NSF/ANSI 58 for reverse osmosis performance (up to 91.9% TDS reduction) and NSF/ANSI 372 for lead-free materials.
Can I use it on well water? Waterdrop rates it for municipal supply. After a softener and iron filter it runs fine on most wells, but it doesn't address bacteria; see RO for well water or call us with your test.
How much water does it waste? One gallon to drain per gallon purified, versus 3–4 for a tank-style RO. The G3P600 and G3P800 improve on that further (2:1 and 3:1).
How long do filters last? Pre-filter 6 months, carbon block 12, membrane 24, on typical city water; the faucet tells you when.
All tankless and tank models: under sink reverse osmosis systems. All Waterdrop: Waterdrop. Save on filters and systems: Waterdrop coupon codes.
Waterdrop G3 Tankless Reverse Osmosis System (400 GPD) Reviews
