iSpring RO500AK Alkaline Reverse Osmosis System
- Reverse osmosis, tankless, with an alkaline remineralization stage
- 500 GPD rating, **0.4 gpm** maximum flow
- 2:1 pure to drain ratio, auto flush
- Up to 1000 ppm supply TDS, **2 year** filter life
- Faucet, tubing, adapter and drain saddle included
- 17.5 x 5.2 x 16.25 in, **21 lb**, corded power
Last refreshed Aug 4, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
An under-sink RO kit with a brushed nickel faucet and fittings in the box, aimed at TDS and PFAS reduction. It needs an outlet and a clear space under the sink.
As an Amazon Associate I earn from qualifying purchases. ProductDome earns a commission when you buy through links on this page.
ASIN: B09CHBC9CPModel: RO500AKCategory: Water Filtration Systems
Overview
A homeowner adding drinking-water treatment under the kitchen sink gets a tankless reverse osmosis unit that pushes water through a membrane, carbon block and alkaline filter. A faucet, tubing, feed water adapter, drain saddle and power supply come with it.
The low drain ratio, auto flush and filter reminder make it easier to live with than older tank systems. The unit needs power and takes up real cabinet space, and the listing does not say whether the faucet needs a drilled hole.
Who it's for
A homeowner comfortable running a drain saddle and tubing, with room below the sink, gets a full kit. A renter, or anyone who wants a no-tools pitcher, should look at a simpler format.
Pros and cons
- Tankless design, no storage tank
- Low drain ratio
- Auto flush and filter reminder
- Faucet and fittings included
- Needs a power outlet
- Large body for small cabinets
- Faucet drilling needs not stated
Performance notes
Water is pushed at pressure through a membrane that rejects dissolved solids, with a carbon stage ahead of it and an alkaline stage after. Flow is limited by the stated maximum, and low supply pressure or high TDS will slow output and shorten filter life.
Specifications
| Brand | iSpring |
|---|---|
| Model | RO500AK |
| Dimensions & fit | |
| Dimensions | 17.5 x 5.2 x 16.25 in |
| Weight | 21 lb |
| Item Dimensions L X W X H | 17.5"L x 5.2"W x 16.25"H |
| Item Weight | 21 poundshigher than 70% of 41 water filtration systems |
| Capacity & performance | |
| Capacity | 500 gallonshigher than 82% of 46 water filtration systems |
| Filter Life Cycle | 2 years |
| Maximum Flow Rate | 0.4 gpm |
| Lowertemperature Range | 41 degrees F |
| Operating Pressure Range | 15-70 psi |
| Upper Temperature Rating | 100 °F |
| Power & efficiency | |
| Power Source | Corded electric |
| Construction & materials | |
| Material Type | Reverse osmosis membrane, carbon block, PP composite filter, carbon alkaline filter |
| Compatibility & installation | |
| Installation Type | Under sink |
| Included components | |
| Included Components | Tubing, system, feed water adapter, drain saddle, faucet, power supply, manual |
| Warranty & support | |
| Supported Water Tds Level Maximum Ppm | 1000 ppm |
| Warranty Description | 1 year manufacturer |
| Other details | |
| Purification Method | Reverse osmosis |
| Container Type | Box |
| Other Special Features Of The Product | Tankless, Water Saver Technology |
Closest rivals on specs
Waterdrop TSU Ultra Filtration Under Sink Water Filter- Weight 21 vs 14 pounds (+50%)
Waterdrop WD-T4-A Alkaline Reverse Osmosis System 450 GPD- Capacity 500 vs 450 gallons (+11%)
- Weight 21 vs 24.21 pounds (-13%)
Frequently asked questions
How fast does the iSpring RO500AK-BN fill a glass?
The listing says it fills 8 oz in 10 s, with a maximum flow of 0.4 gpm.
Does it reduce TDS and PFAS?
The listing highlights TDS and PFAS reduction and gives a supply TDS maximum of 1000 ppm. It does not give percentages.
Is this a countertop or pitcher filter?
No. It is a tankless under-sink system that needs an outlet.