Shutting off the house water supply to change a leaky shutoff valve can be a big inconvenience. Instead, just add a repair valve and leave the old valve in place.
Piggyback the repair valve onto the old supply valve by threading on the compression fitting.
Install the new valve and supply tube in place of the old tube. Water will flow through the new valve and into the bucket until you can tighten the fittings and shut off the new valve.
Connect the built-in compression “ball” to the old valve and tighten the nut.
A shutoff valve that leaks when it's turned off should be replaced, but if the shutoff is hard to access or if turning off the water supply to the whole house—or all the units in a condominium—is inconvenient, you can sidestep the problem by installing a special repair valve on top of the old supply valve. Valves are available at home centers or online. Once the new valve is in place, simply leave the old valve in the full “on” position and use the new valve whenever you need to shut off the water. The repair valve has a built-in compression fitting on one end that attaches directly to the top of your old valve. The supply tube attaches to the other end. The new valve's “ball” design means you'll never again have to deal with a shutoff problem.
Follow this procedure to install the new valve: Shut off the old supply valve (hint: loosen the packing nut slightly). Water will leak out, so place a bowl under it. Then unscrew the old supply tube. Quickly swap in the new repair valve in the open position on top of the old valve. Tighten the compression fitting, then shut off the new valve. Open the old valve all the way and tighten the packing nut. From that point on, ignore the old valve and use the new one to turn off the water.
Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.
You'll also need a bucket to catch drips
Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.