PVC ball valves are installed in water supply lines for household water use and sometimes in garden watering systems. The valve has an inlet in each end for the supply pipe to enter, and depending on the valve can be cemented to the pipe or tightened in place with nuts. The ball itself has a hole drilled through the center, which when aligned with the supply pipe (by turning the valve handle), allows water to rush through the hole and serve the attached appliances. Loosening the valve is a quick process, but replacement may also be necessary.
Turn the water off at the home's main shut-off valve. Attempt to open and close the valve by turning its handle several times by hand.
Squirt lubricating spray where the valve handle enters into the valve, and wait 20 minutes. Attempt to turn the valve handle again, by hand. If it is still hard to turn, tap the valve slightly with a hammer, and place a pipe wrench around the handle to turn it (position a rag between the handle and wrench to keep the wrench from chewing up the handle). Keep attempting to turn the handle on and off for a few minutes.
Turn the water back on if the valve loosens and keep turning the valve until its looseness reaches an acceptable level. However, if the valve handle refuses to budge, it needs to be replaced.