Plumbing a refrigerator's water and ice supply from a reverse osmosis system is a common upgrade and it works well, giving clear ice and better tasting dispensed water. It is not simply a matter of teeing into the RO line, though: the flow, the pressure and the water chemistry all differ from what a fridge expects, and each causes a recognizable problem.
Why RO ice is better
Cloudy ice is dissolved minerals and trapped air coming out of solution as water freezes from the outside in, concentrating everything in the middle. Reverse osmosis removes most of the dissolved solids before the water reaches the ice maker, so the cubes freeze clearer, taste cleaner and melt without leaving the mineral residue that clouds a drink. Dispensed water improves in the same way, and the fridge's own carbon filter is left with much less to do, which extends its life considerably.
The pressure problem
This is the usual complaint. Refrigerator water valves generally expect a supply pressure well above what an RO tank delivers, and the result of feeding one directly is slow dispensing, small or partly formed ice cubes, and an ice maker that fills incompletely and produces hollow cubes. The fix is a small permeate pump or a booster pump on the line to the fridge, which restores useful pressure. Check the appliance's stated minimum before installing rather than after, since some models tolerate low pressure far better than others.
The other two problems
Volume: an ice maker draws a substantial share of a domestic RO system's daily output, so a small system that comfortably served a drinking tap will empty its tank and leave you waiting. Size the system for the combined duty. And corrosion: RO water is aggressive to some metals, and long runs of copper tubing to a fridge are better replaced with plastic tubing rated for the job. A remineralizing cartridge answers both the aggressiveness and the flat taste, and our refrigerator RO guide covers the options.
Making the connection
Tee off the RO storage tank line rather than the membrane output, so the fridge draws from stored water rather than waiting on production, and fit a shutoff valve at the tee so the fridge can be isolated for servicing. Run the tube where it will not be crushed when the appliance is pushed back, leaving enough slack to pull the fridge out fully. Support the tubing rather than letting it hang on the connections. Then discard the first two or three batches of ice, which carry carbon fines and taste of the new tubing.
Questions people ask about reverse osmosis system for refrigerator
Why is my ice small or hollow after connecting RO?
Low pressure. Fridge valves expect more than an RO tank supplies, so the ice maker fills incompletely. A permeate or booster pump fixes it.
Does RO water make clearer ice?
Yes. Cloudiness is dissolved minerals and air concentrating as water freezes inward, and reverse osmosis removes most of them beforehand.
Where should I tee into the system?
Off the storage tank line rather than the membrane output, with a shutoff valve at the tee so the fridge can be isolated for servicing.
Do I need a bigger RO system?
Often yes. An ice maker draws a substantial share of daily output, so a system sized for a drinking tap alone will run its tank empty.