Bar Harbor OW swimming?

Hello, All!

I'll be in Bar Harbor over 4th of July weekend, and I am wondering which lakes you can swim in the area. 

Is Echo the only one in and around Acadia that allows swimming and is not ocean?  Is there a roped off area, or do guards give you a hard time if you try to swim the whole lake? 

Can you swim in (or would you want to?) in Witch Hole or Lake Wood or others?

Any suggestions would be greatly appreciated!