Refrigerator Water Shut Off Valve

It should be a simple task to add a shutoff valve to the existing line. You probably have 1/4" copper tubing or polyethylene tubing. There are shutoff valves available for either type and they don't require soldering. Cut your existing line where you'd like the valve and take the piece to your home store or a plumbing supply store to get the proper valve. Remember to shut off the line in the basement before doing any disassembly.