Water – How to modify a refrigerator water line to add a shut off valve and flexible pipe

Compression caps are available and suitable, but you do need to be fairly careful when fitting them that you tighten the joint just the right amount. You also need a reasonable amount of room to be able to turn the spanner/wrench.

Soldering will give you the most professional result and can be done in a fairly confined space - as long as you take the necessary precautions to avoid scorching/burning the surroundings.

If you really can't face the thought of soldering the joints then you can get push fit end caps that work very well. You need to make sure you've got a smooth, straight end to get a good fit, so a pipe cutter is the preferred cutting method. You can use a hacksaw, but you will need to then use emery paper on the end to remove the burr.

I think kitchen sinks are 3/8" (but I can never remember). So you'll want a 3/8" female, 1/4" male, 3/8" male tee. You should be able to find one at the local big box, or hardware store.

Something like this

1. Shut off the water using the shutoff valve.
2. Remove the existing supply line.
3. Attach the tee where the supply line used to be.
4. Connect the sink supply to the 3/8" male outlet on the tee.
5. Connect the refrigerator supply to the 1/4" outlet on the tee.

NOTE: Use your preferred pipe dope method (tape or goop), however, since it's a brass fitting dope should not be required.