I have well water with a submersible pump. Not sure of the well or pump depth. This morning when I went to take a shower, there was a lot of air in the water lines - both hot & cold and in all faucets. I've never had this problem before except when the water system was opened for filter replacement (which wasn't recently done).

I ran the faucets for a short time 5-15 seconds and things got back to normal. Perhaps this is a one time occurrence (which I doubt). What would cause this? Would similar symptoms occur if the bladder in the storage tank ruptured? Thanks

What would cause this? Would similar symptoms occur if the bladder in the storage tank ruptured? No! Air can get in your lines only if the pump were sucking air, either from a low water table or a leak in the suction line. If the problem persists calla a pump man to diagnose the problem. Good luck, Tom

Well, the same thing happened the next morning. Called the pump & well guys and they found a crack in the PVC pipe 190' down in the well. They pulled the pump, replaced the well pipes and it is working great. Speedball1, thanks you hit the nail directly on the head.