It is possible that the water in your oil is just condensation. If you use the car for short drives and it does not warm up condensation will get in.
If this amount of water get in your oil the oil level will go up (a lot)

An external water leak is sometimes hard to find, small holes only leak under pressure, usually the water evaporates before you can see it.

The only way to find it is to pressurize the system when the engine is cold.

Rob