Waterdrop G5P700A
#2 in TanklessFull review
For a buyer who wants certified RO with mineralized water and a smart faucet for around $300.
Amazon $309.99$309.99
The Waterdrop G5P700A is the better under-sink reverse osmosis system overall, rated 3.8 to 3.3. The Waterdrop G5P700A leads on filter cost and price. The A. O. Smith AOS-DFRO800 wins on warranty and output. The Waterdrop G5P700A costs $140 less ($309.99 vs $449.99).
A. O. Smith AOS-DFRO800
#8 in TanklessFull review
For a household that wants fast, certified tankless RO for less than most rivals. Buyers without a spare faucet should get the brushed nickel version.
Amazon $449.99 Amazon $484.99$449.99
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 Waterdrop G5P700A for filter cost ($130 a year in replacement filters vs $290 a year in replacement filters) and price ($309.99 vs $449.99).
- Choose the A. O. Smith AOS-DFRO800 for warranty (2-year warranty vs 1-year warranty) and output (800 gallons a day vs 700 gallons a day).
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 | Waterdrop G5P700A | A. O. Smith AOS-DFRO800 |
|---|---|---|
| Overall rating | 3.8/5 | 3.3/5 |
| Certification 25% | 100 certified to NSF/ANSI 58 | 100 certified to NSF/ANSI 58 |
| Filter cost 20% | 41 $130 a year in replacement filters | 0 $290 a year in replacement filters |
| Water wasted 15% | 95 2:1 pure to drain | 50 drain ratio not published (neutral score used) |
| Output 10% | 57 700 gallons a day | 71 800 gallons a day |
| Price 15% | 83 $309.99 | 54 $449.99 |
| Warranty 15% | 0 1-year warranty | 25 2-year warranty |
Specifications
| Waterdrop G5P700A | A. O. Smith AOS-DFRO800 | |
|---|---|---|
| Filtration | ||
| Output | 700 gallons a day | 800 gallons a day |
| Pure to drain | 2:1 | - |
| Stages | 8 | 2 |
| Remineralization | Yes | No |
| NSF/ANSI 58 | Yes | Yes |
| Other certifications | NSF/ANSI 372 | NSF/ANSI 372 |
| Replacement filters | $130 a year | $290 a year |
| Build | ||
| Tank | Tankless | Tankless |
| Booster pump | Yes | - |
| Smart faucet | Yes | No |
| Warranty | 1 year | 2 years |