iSpring RO800G
#14 in TanklessFull review
For big households that want fast tankless RO with low waste and cheap filters. It lacks the third-party certification of pricier rivals.
Amazon $458.99$458.99
The iSpring RO800G is the better under-sink reverse osmosis system overall, rated 3.0 to 2.9. The iSpring RO800G leads on output and filter cost. The iSpring RO600 costs $29 less ($429.99 vs $458.99).
iSpring RO600
#15 in TanklessFull review
For buyers who want fast tankless RO with little wasted water and cheap filters. Pick a certified model if third-party proof of performance matters.
Amazon $429.99$429.99
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 iSpring RO800G for output (800 gallons a day vs 600 gallons a day) and filter cost ($85 a year in replacement filters vs $98 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 | iSpring RO800G | iSpring RO600 |
|---|---|---|
| Overall rating | 3.0/5 | 2.9/5 |
| Certification 25% | 0 no third-party certification | 0 no third-party certification |
| Filter cost 20% | 67 $85 a year in replacement filters | 58 $98 a year in replacement filters |
| Water wasted 15% | 98 2.5:1 pure to drain | 98 2.5:1 pure to drain |
| Output 10% | 71 800 gallons a day | 43 600 gallons a day |
| Price 15% | 53 $458.99 | 58 $429.99 |
| Warranty 15% | 0 1-year warranty | 0 1-year warranty |
Specifications
| iSpring RO800G | iSpring RO600 | |
|---|---|---|
| Filtration | ||
| Output | 800 gallons a day | 600 gallons a day |
| Pure to drain | 2.5:1 | 2.5:1 |
| Stages | 2 | 2 |
| Remineralization | No | No |
| NSF/ANSI 58 | No | No |
| Replacement filters | $85 a year | $98 a year |
| Build | ||
| Tank | Tankless | Tankless |
| Booster pump | Yes | Yes |
| Smart faucet | No | No |
| Warranty | 1 year | 1 year |