Delta Clarifi Tankless RO
#3 in TanklessFull review
For a household that wants a broadly certified tankless system with low running costs and a long warranty. Budget buyers can get similar output for less.
Amazon $799$799
The Delta Clarifi Tankless RO is the better under-sink reverse osmosis system overall, rated 3.7 to 3.6. The Delta Clarifi Tankless RO leads on warranty. The Waterdrop G3P600 wins on price and filter cost. The Waterdrop G3P600 costs $360 less ($439 vs $799).
Waterdrop G3P600
#4 in TanklessFull review
For a household that wants a certified tankless RO system with a smart faucet at a mid-range price. Its NSF 58 listing is the main reason to pick it over cheaper tankless units.
Amazon $439$439
Prices were last checked November 2, 2026 and are subject to change; the price and availability shown by the retailer at the time of purchase apply.
Which should you buy?
- Choose the Delta Clarifi Tankless RO for warranty (5-year warranty vs 1-year warranty).
- Choose the Waterdrop G3P600 for price ($439 vs $799) and filter cost ($145 a year in replacement filters vs $201 a year in replacement filters).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every tankless under-sink reverse osmosis system; a clear win is highlighted. How we rank explains each one.
| Factor weight | Delta Clarifi Tankless RO | Waterdrop G3P600 |
|---|---|---|
| Overall rating | 3.7/5 | 3.6/5 |
| Certification 25% | 100 certified to NSF/ANSI 58 | 100 certified to NSF/ANSI 58 |
| Filter cost 20% | 13 $201 a year in replacement filters | 34 $145 a year in replacement filters |
| Water wasted 15% | 95 2:1 pure to drain | 95 2:1 pure to drain |
| Output 10% | 43 600 gallons a day | 43 600 gallons a day |
| Price 15% | 9 $799 | 56 $439 |
| Warranty 15% | 100 5-year warranty | 0 1-year warranty |
Specifications
| Delta Clarifi Tankless RO | Waterdrop G3P600 | |
|---|---|---|
| Filtration | ||
| Output | 600 gallons a day | 600 gallons a day |
| Pure to drain | 2:1 | 2:1 |
| Stages | 6 | 8 |
| Remineralization | No | No |
| NSF/ANSI 58 | Yes | Yes |
| Other certifications | NSF/ANSI 42, 53, 244, 372, 401 | NSF/ANSI 42, 53, 372 |
| Replacement filters | $201 a year | $145 a year |
| Build | ||
| Tank | Tankless | Tankless |
| Booster pump | - | Yes |
| Smart faucet | - | Yes |
| Warranty | 5 years | 1 year |
| Released | 2024 | - |