I just bought an RO filter for under the sink, and I’d like to run the water to the fridge as well. The problem is that the fridge is on the other side of the room. The water line is a 1/4" plastic, fairly flexible tube.
The simplest plan seems to be to run the line under the house and poke up through the floor. I’m in Santa Barbara, so I don’t have to worry about freezing.
The other plan is to fish it through the walls and up into the attic crawlspace.