This is hella cheap today. Was wondering if you put the correct fitting on the PVC pipe and use one of these?

Seems like it's possible.

 

What are you trying to leak check?

 

It wouldn't work. Your piping system isn't air-tight. You wouldn't be able to pump fast enough to keep it pressurized.

 

Well the price is back up, but I think you guys miss the point of the device. You hook it to an air compressor and adjust the wanted air pressure then fill the tire or whatever. Seems like exactly what you would want.