Troubleshooting a PVC Butterfly Valve

Installing PVC Pipe

A PVC butterfly valve is a very common valve also known as quarter turn. The PVC butterfly valve consists of a metal rod that has a metal disc mounted to it. When you close the butterfly valve you are actually lowering the disc until it blocks the pipe which prevents the flow of water. To open a PVC butterfly valve, you turn it a quarter turn (hence the name) which allows water to flow unrestricted. The valve is found in several styles all around the home and is even found in the car’s carburetor. Like every other kind of valve, the PVC butterfly valve can begin to have problems. The following article will share with you several of these problems and how to troubleshoot an answer.


One of the more common issues with a PVC butterfly valve is that it can begin to drip. If you have closed the valve and water is still dripping out the easiest solution is to plug the leak. There are threaded plugs you can purchase from your local home repair store, which include an o-ring seal. Screw this plug into the threaded opening of the PVC butterfly valve. If a backwash fitting has been installed, you will need to remove it prior to plugging the leak.


If the plug is not working, there may be serious degradation in the valve, and it will need to be replaced. Turn off the water at its source and then turn the knob all the way to the left until it stops. When it stops, continue unscrewing it until it is removed. Wrap the threads of the new valve with silicone plumber’s tape and then screw it in place.

Stuck Valve

There are times when a PVC butterfly valve can become stuck. Forcing the valve could cause it to break off completely, which will create a bigger problem than you had before. At the center of the valve will be a large nut which is the lock nut ring. Use a small adjustable wrench to loosen this nut by turning it to the left. Even if the valve is stuck in place, doing this will free the inside pieces of the butterfly valve. This should let you close the valve (or open it). If the knob is broken off then a pair of pliers will also do the trick.

Routine Cleaning

Many times all that is needed is a routine cleaning of the butterfly valve. Remove the valve by spinning it past hard left. Loosen the lock nut on the stem and then pull the inner mechanics out of the valve. Clean the inside of the pipe with a rag. Take the valve apart using a screwdriver or pliers and soak the other parts in water with a few drops of oil-free dish soap. Wipe them all down after a few minutes and reassemble the PVC butterfly valve. You can then replace it inside the pipe and turn the valve knob back on the stem.