
iSpring RCC7AK
Score: 88/100
Express Water RO5DX
Score: 88/100Rankings

The iSpring RCC7AK is a 6-stage under-sink reverse osmosis system designed to remove up to 99% of over 1,000 harmful contaminants while restoring beneficial minerals and alkalinity. It features NSF/ANSI 58 certification for the entire system and produces high-quality drinking water with a neutral pH through its dedicated remineralization stage. It is a superior choice for health-conscious consumers prioritizing pH balance and mineral content.

The Express Water RO5DX is a compact 5-stage under-sink reverse osmosis system featuring NSF/ANSI 58 certification and alkaline remineralization for improved taste. It offers a 50 GPD production rate and includes a leak detection shutoff for added safety. While it lacks the high capacity of larger systems, its pre-assembled design and remineralization feature make it a strong contender for standard households.
| Attribute | ![]() | ![]() |
|---|---|---|
6 stagesbest | 5 stages | |
75 gallons per daybest | 50 gallons per day | |
93 percent | 96 percentbest | |
— | 4 gallonsbest | |
1,000 countbest | 1,000 countbest | |
— | 12 monthsbest | |
| ↓ lower better | 5.1 inches | 5 inchesbest |
| ↓ lower better | 19 inches | 15 inchesbest |
Click an attribute name to sort · Green = best, red = worst (relative to this comparison)
| Attribute | ![]() | ![]() |
|---|---|---|
Storage(1) | ||
Storage Tank Capacity (gallons) | null gallons | 4 gallons |
General(1) | ||
Installation Type | Under Sink | Under-sink |
Design(2) | ||
System Width (inches) | 5.10 inches | 5.0 inches |
System Height (inches) | 19.00 inches | 15.0 inches |
Performance(4) | ||
Filtration Stages (stages) | 6 stages | 5 stages |
Daily Production Rate (gallons per day) | 75 gallons per day | 50 gallons per day |
TDS Reduction Rate (percent) | 93 percent | 96 percent |
Feed Water Pressure (PSI) | 45 PSI | 40 PSI |
Features(1) | ||
Faucet Type | Top-Mounted | Chrome |

Products in the top-left offer the best value (high score, low price).

Professional reviewers emphasize the iSpring RCC7AK's full-system NSF/ANSI 58 certification as a key market differentiator, noting that many competitors only certify individual components. Experts highlight the alkaline remineralization stage as a critical feature that solves the prevalent issue of standard RO systems producing slightly acidic, flat-tasting water.
Everyday users consistently praise the ease of installation, noting that color-coded tubing and step-by-step instructions make the process manageable for DIY enthusiasts. Users report significantly improved water taste due to the remineralization stage, with some calling it the best RO system available.

“the best RO system out there”




Professional reviewers highlight the RO5DX's NSF/ANSI 58 certification as a key strength, validating its TDS reduction capabilities and material safety.
Users generally praise the system for its reliable performance, compact size, and the peace of mind provided by NSF certification.