I don't know what their specific zoning laws are but California is pushing to make it easier to have in law units sometimes called ADU for accessory dwelling units.

Ideally, I would love for it to be a house-hack that allows me to live for much cheaper especially because I am in an expensive market (Long Island) In my search for duplexes i see that some are listed as “legal 2 families” while others are listed as “accessory apartments”.

Just adding in a few little accessories like an accent chair, lamp, shower curtain, entry hall rug, towels in the bathroom, decorative item on the kitchen counter, etc can make a rental house really stand out since most people don't do this.

I am looking to buy a property with an accessory dwelling unit but was informed by the zoning department that either the primary house or accessory unit would need to be occupied by the owner.

There are many municipalities in which you can have an accessory apartment in your basement without much difficulty.

As long as the furniture and accessories fit the style of the house, i.e. contemporary, cottage, etc., the stagers have done their job. 

Accessory to a Federal crime carries a few years of free room and board as well!

It is zoned for an ADU (Accessory Dwelling Unit).

However, it even says in the listing that the city doesn't recognize the apartment as a legal accessory apartment.

.- $8,000.00 2) Remove and replace Bathroom (new tub or shower, new vanities and toilet, ceramic tile, paint, bath accessories). - $4,000.00 3) Frame and finish basement - $6,000.00 (with full second bath included will run about $10,000.)4) Painting a property of this size including the finished basement - $2,500.005) Remove and replace all doors (about 10 in this property) with 6 panel hollow doors - $15,000.006) Install HVAC to include Furnace, condenser and ductwork - $7,500 (If the ductwork is already in place we can have a 2.5 ton furnace and condenser installed for $4,000.00(ductwork is the most consuming and labor intensive part of installing a HVAC system)7) Install carpet on second floor(This includes all three bedrooms, hallway and stairs) and basement $2,300.008) Refinish hardwood floor and new color of the stain of for the living room and dining room - $ 900.009) Replace windows with all new energy efficient vinyl windows - $3,000.00I think that's all of the big stuff.