Adding two basement bedrooms to a raised ranch

[Mark Ross]

Hi everyone. My wife and I purchased our 2nd rental unit and have put a tenant in the main floor. Life is good! We would like to add 2 bedrooms, a bath, a kitchen (kitchenette) and a living room in the existing walkout basement.

My 2 questions are surrounding the rules of a legal two family...vs an in-law apartment...vs Airbnb

1). Does the town dictate what I do or can I convert a property to be a legal second apartment... Or a legal in-law? I live near a very nice, clean swimmable pond and would entertain Airbnb or another family to live in the basement. It's a walk out basement and very easy to convert.

2). I currently have a fairly new three-bedroom septic. I'm told it's about five years old. How do I go about making my two new bedrooms and bath work for the existing septic? Do I add another tank and more leech fields or do I simply pump my tank more frequently? With that many bedrooms in the house would the waste water leaving the house even flow quick enough to dissipate?... Or would the tank and leach fields over saturate?

I have no problem doing the right thing... I just don't know, what I don't know, regarding these 2 questions !

Thank you all in advance

Mark