PVC stands for polyvinyl chloride, a hard plastic pipe used in cold water plumbing and irrigation. PVC is used only with cold water because the high heat of appliances such as dish and clothes washers melts the cement that holds sections of PVC pipe together. So the trick to taking PVC pipe sections apart is to to apply just enough heat to melt the adhesive.
Rent or purchase an industrial heat gun, which looks much like an oversized, hand-held hair blow dryer.
Plug the heater in and turn it on.
Aim the heater at the cemented PVC joint.
Hold the heater pointed at the joint for a minute or two, then turn the heater off and test the joint. If the joint is wobbling and is softening, try to separate the pipes. If not, reapply the heat.
Heat the joint until the PVC cement softens and the pipes come apart.
Keep fingers away from the heat stream as the heat burns skin. Do not use stronger heat sources for this task as the goal is to melt only the cement without melting the plastic pipe itself.