Unplug the refrigerator's power cord from the electrical outlet.
Move the refrigerator sideways to access the back and locate the water supply near the bottom of the refrigerator.
Turn the water shutoff valve clockwise to turn off the water. Turning off the water is necessary to prevent water leaks while troubleshooting the water supply.
Rotate the compression nut on the water supply clockwise to tighten the water supply's connection to the refrigerator. Continue to turn the compression nut with your thumb and forefinger until it no longer moves.
Turn the compression nut clockwise 360 degrees with the wrench to secure the compression nut in place. Twist the water shutoff valve counterclockwise to disable the shutoff valve and restore water to the refrigerator.
Plug the fridge's power cord back into the electrical outlet.