About this Project

Any time a water line bursts, a faucet needs repair, or a toilet needs replacing, you’ll be grateful to have a stop valve in the right place. Without one of these handy devices, you may have to shut off the water to the entire house simply to change a faucet washer. If you have an older home that lacks stop valves under sinks and toilets, plan to install them.

No matter what the material or size of your pipes, there’s a stop valve made to order. With copper lines, use brass valves. Galvanized and plastic pipes take steel and plastic stop valves respectively. You can also use a transition fitting to change material just prior to the stop. If the valve will be in view, choose a chrome finish.

To make the connection from a stop valve to a sink or toilet, you can use flexible copper or plastic line. Or throw away the nut and ferrule that come with the valve, and use the handy plastic or braided-metal flexible supply lines that simply screw on.

Time: About two hours to cut a pipe, install a stop valve, and run flexible line to the fixture.

Skills: Cutting, connecting pipe.

Measurement Tip

Match the Valve with the Flexible Line Stop valves for sinks and toilets come with either 1/2- or 3/8-inch outlets. Make sure your flexible line is the same size.

Step-by-Step

Where stop valves are needed

To determine your stop valve needs, simply take a look at your home’s plumbing fixtures. Sinks, tubs, showers, and clothes washers should have one on both the hot and cold lines. Toilets and water heaters require only one, on the cold water line, and dishwashers need one on the hot line only. Check the water meter, too. It should have a valve just beyond it.

1. Cut pipe or tubing

In the example shown, the existing plumbing consists of galvanized pipe and flexible copper tubing. To make room for the stop valve, cut enough tubing off to make room for the valve. Leave enough supply to fit the compression fitting and allow for tightening the stop valve on the steel pipe.

2. Install the valve

One end of the stop valve is sized to fit regular pipe, and the other receives compression-fitted flexible lines. Wrap the galvanized pipe clockwise with Teflon tape, and install the stop valve. Slip the copper line into the other end, and tighten the compression fitting, holding the stop valve in place with a second wrench.

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