For buyers who want certified RO water with minerals added back for taste, at a low price. Choose a tankless system instead if cabinet space or wasted water matters more.
Amazon $199.99The iSpring RCC7AK is the better under-sink reverse osmosis system overall, rated 3.6 to 3.5. The iSpring RCC7AK leads on filter cost. The APEC ROES-PH75 costs $10 less ($189.99 vs $199.99).
For buyers who want a certified tank RO system with remineralization at a low price and can accept high water waste.
Amazon $189.99Prices 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 RCC7AK for filter cost ($95 a year in replacement filters vs $133 a year in replacement filters).
Scores side by side
Each factor is scored 0-100 against the same fixed reference points for every with tank under-sink reverse osmosis system; a clear win is highlighted. How we rank explains each one.
| Factor weight | iSpring RCC7AK | APEC ROES-PH75 |
|---|---|---|
| Overall rating | 3.6/5 | 3.5/5 |
| Certification 25% | 100 certified to NSF/ANSI 58 | 100 certified to NSF/ANSI 58 |
| Filter cost 20% | 60 $95 a year in replacement filters | 39 $133 a year in replacement filters |
| Water wasted 15% | 50 drain ratio not published (neutral score used) | 50 drain ratio not published (neutral score used) |
| Output 10% | 50 75 gallons a day | 50 75 gallons a day |
| Price 15% | 76 $199.99 | 80 $189.99 |
| Warranty 15% | 0 1-year warranty | 0 1-year warranty |
Independent measurements
iSpring RCC7AK
| Tested by | TDS reduction | Output | Pure to drain | Conditions |
|---|---|---|---|---|
| Water Filter Guru | 93 % | 35.3 gpd | 0.5 :1 | RCC7-AK tested without a booster pump on 635 ppm feed water: 44 ppm after 2 minutes of flow (114 ppm on first draw after 10 hours idle). 12 oz filled in 230.18 s; 64 oz of pure water sent 137 oz to drain (1:2.14). Date is the review update date. |
APEC ROES-PH75
| Tested by | TDS reduction | Output | Pure to drain | Conditions |
|---|---|---|---|---|
| Water Filter Guru | 93.8 % | 42.7 gpd | 0.2 :1 | Tap Score lab test: 875 ppm TDS before, 54 ppm after. Flow measured without a booster pump (12 oz in 189.47 s); 64 oz of pure water sent 328 oz to drain (1:5.1). Date is the review update date. |
Specifications
| iSpring RCC7AK | APEC ROES-PH75 | |
|---|---|---|
| Filtration | ||
| Output | 75 gallons a day | 75 gallons a day |
| Stages | 6 | 6 |
| Remineralization | Yes | Yes |
| NSF/ANSI 58 | Yes | Yes |
| Other certifications | NSF/ANSI 372 | NSF/ANSI 372 |
| Replacement filters | $95 a year | $133 a year |
| Build | ||
| Tank | 3.2 gal | 4 gal |
| Booster pump | No | No |
| Smart faucet | No | No |
| Warranty | 1 year | 1 year |
