Under Sink & Kitchen Water Systems
An under sink water filter keeps treatment out of sight and puts filtered drinking water on its own tap at the kitchen sink. This collection covers everything that lives in the cabinet: the ECHO RO under sink reverse osmosis system, the Echo Flow under-sink hydrogen machine, dedicated faucets, replacement filters and the Echo Guard leak detection kit.
How to choose an under sink water filter
Under-sink systems succeed or fail on fit, so check your cabinet before you compare anything else.
- Space: the ECHO RO measures 17.75 in wide, 16 in tall and 4.25 in deep, and Echo recommends 5 in of clear depth. It stands against the back wall, with no storage tank taking up the shelf.
- Connections: the ECHO RO tees off the cold water supply, connects to the drain with a saddle valve and plugs into a standard outlet.
- A faucet hole: RO water runs to a dedicated faucet beside your main one. Many counters already have a spare hole, such as one used for a soap dispenser.
- What you want from the tap: the ECHO RO filters. The Echo Flow does not filter; it adds hydrogen to water that has already been filtered.
Compare Echo under sink products
| Product | What it does | What it needs |
|---|---|---|
| ECHO RO | Tankless, 4-stage under sink reverse osmosis system; 1.2 L/min on demand | Cold supply, drain, standard outlet, dedicated faucet |
| Echo Flow | Filterless unit that adds up to 1.21 ppm dissolved hydrogen; feeds a faucet, fridge or ice maker | RO or whole-house prefiltration upstream (minimum 10 psi), power, faucet |
| Echo RO/Flow Faucet | Secondary drinking-water faucet for the ECHO RO and Echo Flow | A countertop hole |
| Echo H2 Faucet | Secondary faucet for the Echo H2 machine, with an optional installation kit | A countertop hole |
| Echo RO Filters | Replacement cartridges for the ECHO RO, as a set or individually | An ECHO RO |
| Echo Guard | Leak detector and alarm, emergency shutoff valve, surge protector and silicone mat | The RO (3/8") or Ultimate/H2 (1/4") hookup version |
What's included and maintenance
The ECHO RO comes with its four cartridges, tubing, power adapter, drain clamp, T-valve and clips, with a faucet in chrome, stainless or matte black as an option. Echo recommends changing the sediment and carbon block cartridges every 6–12 months, the post carbon cartridge about every 12 months and the membrane every 2–3 years, depending on your water. The unit's display shows cartridge life for each stage.
The Echo Flow has no filters of its own; your prefiltration keeps its own schedule. Warranties: 5 years on the ECHO RO and the Echo RO/Flow Faucet, and a 10-year limited warranty on the Echo Flow, which excludes running it without the required prefiltration.
Want the full checklist? Read our under-sink reverse osmosis system buyer's guide before you order.
Under sink water filter FAQ
Will an under sink reverse osmosis system fit my cabinet?
The ECHO RO is 4.25 inches deep, and Echo recommends 5 inches of clear depth. If you're unsure, Echo's team will walk through your cabinet with you before you order.
Do I need a separate faucet?
Yes. Filtered water runs to a dedicated tap next to your main faucet. Choose a finish when you order, or pick "no faucet" if you already have a compatible one.
Can the ECHO RO and Echo Flow share one cabinet?
Yes. Run the RO first and the Flow after it, so the Flow receives purified water. Echo designed the two to install in the same cabinet on the same faucet. Unfiltered city or well water should not go straight into the Flow.
Under sink or whole house?
An under-sink system treats one drinking tap. For showers, laundry and every other tap, see whole house water filters, or compare both approaches in reverse osmosis systems.