Maybe neither. You'll get natural condensation every time you shut the engine off and the exhaust cools. The water sits in the muffler/tailpipe and is expelled when you start the engine. The water boiling off is what causes the white exhaust in cold weather. If you get water in the oil you may have a bad gasket or cracked head. If it's only the tailpipe it's probably normal.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.