Have separate addresses, and utility hookups. And I have no mortgage on either of them.
You can do either way. But what may be best depends on one factor we don't know.
Before the ADU, did you receive one property tax bill for everything?
After the ADU, do you still receive one tax bill for both structures and the land they are on? Did you take necessary actions to sub-divide so that each property is taxed separately now by your property taxing authority? (The county I presume.)
