How To Install A Shutoff Valve To A PVC Pipe

If your house doesn't have a main water shutoff, you should install one, and if you have PVC plumbing, you need a PVC water shutoff valve. Actually, if your plumbing is code compliant, the pipes will be CPVC, not PVC, but in terms of installing a shutoff valve, that's basically the same thing. CPVC pipe, which is rated for use with hot water, is cream-colored, not white like PVC.

You may already have a main shutoff (most houses do), but you may need one on a branch line to the bathroom or the irrigation system. You may also need a new toilet shutoff if you're remodeling the bathroom and moving the toilet. As long as the pipes are PVC or CPVC, the job of installing a valve is easy.

PVC inline shutoff valves are ball valves, which means the shutoff mechanism is a ball with a hole in it. When you turn the plastic handle, you orient the hole either in the direction of the flow or against it. The input ports are the same diameter as the pipe on which you install the valve, and they are slip connectors that you glue to the pipe with PVC or CPVC cement depending on the type of pipe.

Before installing a shutoff valve, you have to turn off the water, of course, and then you need to cut out a section of pipe to make room for the valve. To determine the length of this section, measure the length of the valve and subtract about 1 1/2 inches to leave enough pipe to make the glue connection. The cuts will be as straight and clean as possible if you use a PVC pipe cutter rather than a hacksaw (which is also an option). Once the pipe is cut, spread primer and glue on the ends of the pipes and the ports of the valves and glue the valve in place.

If your house has CPVC plumbing, you would expect to be able to find CPVC toilet shutoff valves, but metal ones are more common. Some have a CPVC inlet port, and others have a compression fitting. The ones with plastic ports are easiest to use because you can just glue them onto the CPVC pipe stubbing out from behind the toilet.

Because plastic-lined valves are so easy to install, there's little need to use a compression stop on CPVC pipe. If you decide to go this route, you'll need a fitting designed specifically for CPVC because it has a different outside diameter than copper. It comes with a compression nut and ring that you slide onto the pipe. The nut screws onto the valve, tightening the ring into the gap between the fitting and the pipe to make a watertight connection.

The procedure for installing a valve on CPVC pipe couldn't be easier, which is one of the benefits of CPVC plumbing.

1. Cut the stubout pipe to the correct length using a pipe cutter. Make sure you leave at least an inch of pipe sticking out from the wall.
2. Spread CPVC primer on the end of the pipe and on the inside of the valve using the applicator in the primer can.
3. Spread CPVC cement on the pipe and the valve in the same way and then immediately slide the valve onto the pipe and push it as far as it will go.
4. Give the valve a quarter turn to evenly distribute the glue and then let the cement cure for the time recommended on the container before turning on the water.