Waterdrop G3P600 vs G3P800: Which Tankless RO to Buy
The Waterdrop G3P600 and G3P800 are the same size, weigh the same, and use the same filter schedule. The G3P800 makes more water (800 vs 600 gallons per day), wastes less of it (3:1 vs 2:1 pure to drain), and adds NSF/ANSI 53 certification. On October 20, 2026 it cost $330 more on sale, and its filters run about $15 more a year. For most kitchens the G3P600 is enough. The G3P800 is worth it if the extra NSF/ANSI 53 certification or less waste water matters to you.
Side-by-side specs
Everything below comes from Waterdrop’s own comparison table on both product pages, checked October 20, 2026.
| G3P600 | G3P800 | |
|---|---|---|
| Flow rate | 600 gallons per day | 800 gallons per day |
| Pure to drain ratio | 2:1 | 3:1 |
| Filtration stages | 8 | 10 |
| Certification | NSF/ANSI 42, 58, 372 | NSF/ANSI 42, 53, 58, 372 |
| Size (inches) | 18.11 x 5.67 x 17.73 | 18.11 x 5.67 x 17.73 |
| Weight | 32.4 lb | 32.4 lb |
| Filter lifespan | CF 6 months, CB 12 months, RO 24 months | CF 6 months, CB 12 months, RO 24 months |
| Average annual filter cost | $144.97 | $159.97 |
| Warranty | 1 year | 1 year |
| Price, Oct 20, 2026 | $429 (list $539) | $759 (list $999) |
Both need an outlet under the sink, both are tankless, and both come with a faucet that shows the TDS reading and filter life.
What the extra $330 buys
NSF/ANSI 53 certification
This is the difference that matters most. Waterdrop says the G3P800 is certified by IAPMO R&T to NSF/ANSI 42, 53 and 58 for the claims on its Performance Data Sheet, and to NSF/ANSI 372 for low lead. For the G3P600 it lists IAPMO R&T certification to NSF/ANSI 58 and 372, with no 53. The G3P800 page names lead, chromium, fluoride and PFAS among the substances it reduces. If you are buying because of a specific contaminant like lead, read the Performance Data Sheet for the model before you order.
Less waste water
At 2:1, the G3P600 sends about half a gallon down the drain for every gallon it makes. At 3:1, the G3P800 sends about a third of a gallon. If your household drinks and cooks with 3 gallons of filtered water a day, that is roughly 1.5 versus 1 gallon of drain water a day, or about 180 gallons a year. It is a real saving, though a small one on most water bills.
Faster flow
Waterdrop says the G3P800 fills a 6 oz cup in about 5 seconds and the G3P600 in about 6.5. Neither has a tank to wait on, so both feel quick at the faucet. The extra capacity helps most if you fill large pots or several bottles at once.
Replacement filters
Both systems use three filters on the same schedule: a CF filter every 6 months, a CB filter every 12 months, and the RO membrane every 24 months. Waterdrop sells one CF filter for both models. The RO filters differ: the WD-G3P600-RO for the G3P600 and the WD-G3P800-N2RO for the G3P800, which costs more. Waterdrop puts the average yearly cost at $144.97 for the G3P600 and $159.97 for the G3P800. The G3P800 product page lists its RO filter at 24 months or 2,900 gallons, whichever comes first.
Check current prices: Waterdrop G3P600 · Waterdrop G3P800 at Waterdrop. Sale prices change often. (Affiliate links: we may earn a commission at no cost to you.)
Which one should you buy?
- Buy the G3P600 if you want tankless RO for drinking and cooking water for a typical household, and the price gap matters.
- Buy the G3P800 if you want the extra NSF/ANSI 53 certification, you want less waste water, or you draw a lot of water at once.
- Either way, you need a cold water line, a drain connection and an outlet under the sink, and about 18 x 6 x 18 inches of space.
Not sure RO is the right kind of filter for you? See our water filter guides, including the GE and Whirlpool under-sink filter page.
Frequently Asked Questions
Do the G3P600 and G3P800 use the same filters?
Partly. Both use the same CF filter and the same 6, 12 and 24 month schedule, but the RO filter is model-specific: the WD-G3P600-RO for the G3P600 and the WD-G3P800-N2RO for the G3P800.
Is the G3P800 bigger than the G3P600?
No. Waterdrop lists both at 18.11 x 5.67 x 17.73 inches and 32.4 pounds.
Which one wastes less water?
The G3P800. Its pure to drain ratio is 3:1, against 2:1 for the G3P600.
Sources: Waterdrop G3P600 product page; Waterdrop G3P800 product page, including the comparison table on both, checked October 20, 2026.