One trick you can do (if you have an air compressor) is to push air through one end of the piping. You're going to have to open then no matter what. Or just open all the faucets when you shut the water off, that should be enough.
first you shut the main water off to the house your local water department can show you where this is once that is shut off you must open every faucet in the house let them drain then shut back off
